WDIFF

draft-ietf-calsch-ical-06.txt --> draft-ietf-calsch-ical-07.txt

Network Working Group Frank Dawson, Lotus
Internet Draft Derik Stenerson, Microsoft
<ietf-calsch-ical-06.txt> March 13, 1998
<draft-ietf-calsch-ical-07.txt
Expires September six months after May 11, 1998

Internet Calendaring and Scheduling Core Object Specification
(iCalendar)

Status of this Memo

This memo is an Internet-Draft. Internet-Drafts are working documents
of the Internet Engineering Task Force (IETF), its areas, and its
working groups. Note that other groups MAY can also distribute working
documents as Internet-Drafts.

Internet-Drafts are draft documents valid for a maximum of six
months. Internet-Drafts MAY can be updated, replaced, or made obsolete by
other documents at any time. It is not appropriate to use Internet-
Drafts as reference material or to cite them other than as a "working
draft" or "work in progress".

To learn view the current status entire list of any Internet-Draft, current Internet-Drafts, please check
the
1id-abstracts.txt "1id-abstracts.txt" listing contained in the Internet-Drafts
Shadow Directories on ds.internic.net ftp.is.co.za (Africa), ftp.nordu.net
(Northern Europe), ftp.nis.garr.it (Southern Europe), munnari.oz.au
(Pacific Rim), ftp.ietf.org (US East Coast), nic.nordu.net
(Europe), or ftp.isi.edu
(US West Coast), or munnari.oz.au (Pacific
Rim). Coast).

Distribution of this memo is unlimited.

Abstract

There is a clear need to provide and deploy interoperable calendaring
and scheduling services for the Internet. Current group scheduling
and Personal Information Management (PIM) products are being extended
for use across the Internet, today, in proprietary ways. This memo
has been defined to provide the definition of a common format for
openly exchanging calendaring and scheduling information across the
Internet.

This memo is formatted as a registration for a MIME media type per
[RFC 2048]. However, the format in this memo is equally applicable
for use outside of a MIME message content type.

The proposed media type value is ''text/calendar''. 'text/calendar'. This string would
label a media type containing calendaring and scheduling information
encoded as text characters formatted in a manner outlined below.

This MIME media type provides a standard content type for capturing
calendar event, to-do and journal entry information. It also can be
used to convey free/busy time information. The content type is
suitable as a MIME message entity that can be transferred over MIME
based email systems, using HTTP or some other Internet transport. In

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addition, the content type is useful as an object for interactions
between desktop applications using the operating system clipboard,
drag/drop or file systems capabilities.

This memo is based on the earlier work of the vCalendar specification
for the exchange of personal calendaring and scheduling information.
In order to avoid confusion with this referenced work, this memo is
to be known as the iCalendar specification.

Readers may also wish to refer to the calendaring and scheduling model
defined in [] [ICMS] for a description of this Internet application.

This memo defines the format for specifying iCalendar object methods.
An iCalendar object method is a set of usage constraints for the
iCalendar object. For example, these methods might define scheduling
messages that request an event be scheduled, reply to an event
request, send a cancellation notice for an event, modify or replace
the definition of an event, provide a counter proposal for an
original event request, delegate an event request to another
individual, request free or busy time, reply to a free or busy time
request, or provide similar scheduling messages for a to-do or
journal entry calendar component. The iCalendar Transport-indendent
Interoperability Protocol (iTIP) defined in [ITIP] is one such
scheduling protocol.

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Table of Contents

1 Introduction.........................................................8 Introduction.........................................................6
2 Basic Grammar and Conventions........................................8 Conventions........................................6
2.1 Formatting Conventions ...........................................9 ...........................................7
2.2 Related Memos ...................................................10 ....................................................8
2.3 International Considerations .....................................8
3 TEXT/CALENDAR Registration Information..............................10 Information.............................................8
3.1 Content Type .....................................................9
3.2 Parameters .......................................................9
3.3 Content Header Fields ...........................................10
3.4 Encoding Considerations .........................................10
3.5 Security Considerations .........................................10
3.6 Interoperability Considerations .................................11
3.7 Applications Which Use This Media Type ..........................11
3.8 Additional Information ..........................................11
3.9 Magic Numbers ...................................................11
3.10 File Extensions ................................................11
3.11 Contact for Further Information: ...............................12
3.12 Intended Usage .................................................12
3.13 Authors/Change Controllers .....................................12
4 iCalendar Object Specification......................................13 Specification......................................12
4.1 Content Lines ...................................................13 ...................................................12
4.1.1 List and Field Separators ....................................16 ....................................15
4.1.2 Multiple Values ..............................................16 ..............................................15
4.1.3 Binary Content ...............................................17 ...............................................16
4.1.4 Character Set ................................................17 ................................................16
4.2 Property Parameters .............................................17 .............................................16
4.2.1 Alternate Text Representation ................................18 ................................17
4.2.2 Common Name ..................................................18
4.2.3 Calendar User Type ...........................................19
4.2.4 Delegators ...................................................19
4.2.5 Delegatees ...................................................20
4.2.6 Directory Entry Reference ....................................20
4.2.7 Inline Encoding ..............................................19
4.2.3 ..............................................20
4.2.8 Free/Busy Time Type ..........................................21
4.2.9 Language .....................................................19
4.2.4 .....................................................22
4.2.10 Group or List Membership ....................................22
4.2.11 Participation Status ........................................23
4.2.12 Recurrence Identifier Range .................................24
4.2.13 Alarm Trigger Relationship ..................................25
4.2.14 Relationship Type ...........................................25
4.2.15 Participation Role ..........................................26
4.2.16 RSVP Expectation ............................................27
4.2.17 Sent By .....................................................27
4.2.18 Time Zone Identifier .........................................20
4.2.5 ........................................27
4.2.19 Value Data Types .............................................21 ............................................28
4.3 Property Value Data Types .......................................21 .......................................29
4.3.1 Binary .......................................................22 .......................................................29
4.3.2 Boolean ......................................................22 ......................................................30
4.3.3 Calendar User Address ........................................23 ........................................30
4.3.4 Date .........................................................23 .........................................................31

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4.3.5 Date-Time ....................................................24 ....................................................31
4.3.6 Duration .....................................................25 .....................................................33
4.3.7 Float ........................................................26 ........................................................34
4.3.8 Integer ......................................................27 ......................................................34
4.3.9 Period of Time ...............................................27 ...............................................35
4.3.10 Recurrence Rule .............................................28 .............................................36
4.3.11 Text ........................................................33 ........................................................40
4.3.12 Time ........................................................34 ........................................................41
4.3.13 URI .........................................................36 .........................................................43
4.3.14 UTC Offset ..................................................36 ..................................................44
4.4 iCalendar Object ................................................37 ................................................45
4.5 Property ........................................................38 ........................................................45
4.6 Calendar Components .............................................38 .............................................45
4.6.1 Event Component ..............................................38 ..............................................46
4.6.2 To-do Component ..............................................40 ..............................................48
4.6.3 Journal Component ............................................41 ............................................49
4.6.4 Free/Busy Component ..........................................43 ..........................................50
4.6.5 Timezone Time Zone Component ...........................................45 ..........................................52
4.6.6 Alarm Component ..............................................50 ..............................................58
4.7 Calendar Properties .............................................53 .............................................61
4.7.1 Calendar Scale ...............................................54 ...............................................61
4.7.2 Method .......................................................54 .......................................................62
4.7.3 Product Identifier ...........................................55 ...........................................63
4.7.4 Version ......................................................56 ......................................................63
4.8 Component Properties ............................................56 ............................................64
4.8.1 Descriptive Component Properties .............................56 .............................64
4.8.1.1 Attachment ...............................................56 ...............................................64
4.8.1.2 Categories ...............................................57

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4.8.1.3 Classification ...........................................58 ...........................................66
4.8.1.4 Comment ..................................................59 ..................................................67
4.8.1.5 Description ..............................................59 ..............................................67
4.8.1.6 Geographic Position ......................................60 ......................................68
4.8.1.7 Location .................................................61 .................................................69
4.8.1.8 Percent Complete .........................................61 .........................................69
4.8.1.9 Priority .................................................62 .................................................70
4.8.1.10 Resources ...............................................63 ...............................................72
4.8.1.11 Status ..................................................64 ..................................................72
4.8.1.12 Summary .................................................65 .................................................73
4.8.2 Date and Time Component Properties ...........................66 ...........................74
4.8.2.1 Date/Time Completed ......................................66 ......................................74
4.8.2.2 Date/Time End ............................................66 ............................................75
4.8.2.3 Date/Time Due ............................................67 ............................................75
4.8.2.4 Date/Time Start ..........................................68 ..........................................76
4.8.2.5 Duration .................................................69 .................................................77
4.8.2.6 Free/Busy Time ...........................................69 ...........................................78
4.8.2.7 Time Transparency ........................................71 ........................................79
4.8.3 Time Zone Component Properties ...............................72 ...............................79
4.8.3.1 Time Zone Identifier .....................................72 .....................................79
4.8.3.2 Time Zone Name ...........................................72 ...........................................80
4.8.3.3 Time Zone Offset From ....................................73 ....................................81
4.8.3.4 Time Zone Offset To ......................................74 ......................................82
4.8.3.5 Time Zone URL ............................................74 ............................................82
4.8.4 Relationship Component Properties ............................75 ............................83
4.8.4.1 Attendee .................................................75 .................................................83

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4.8.4.2 Contact ..................................................78 ..................................................85
4.8.4.3 Organizer ................................................79 ................................................86
4.8.4.4 Recurrence ID ............................................80 ............................................87
4.8.4.5 Related To ...............................................81 ...............................................88
4.8.4.6 Uniform Resource Locator .................................82 .................................89
4.8.4.7 Unique Identifier ........................................83 ........................................90
4.8.5 Recurrence Component Properties ..............................84 ..............................91
4.8.5.1 Exception Date/Times .....................................84 .....................................91
4.8.5.2 Exception Rule ...........................................85 ...........................................92
4.8.5.3 Recurrence Date/Times ....................................86 ....................................93
4.8.5.4 Recurrence Rule ..........................................88 ..........................................95
4.8.6 Alarm Component Properties ...................................95 ..................................102
4.8.6.1 Alarm Type ...............................................96 Action ..................................................103
4.8.6.2 Repeat Count .............................................96 ............................................103
4.8.6.3 Trigger ..................................................97 .................................................104
4.8.7 Change Management Component Properties .......................98 ......................105
4.8.7.1 Date/Time Created ........................................98 .......................................105
4.8.7.2 Date/Time Stamp ..........................................99 .........................................106
4.8.7.3 Last Modified ............................................99 ...........................................107
4.8.7.4 Sequence Number .........................................100 .........................................107
4.8.8 Miscellaneous Component Properties ..........................101 ..........................109
4.8.8.1 Non-standard Properties .................................101 .................................109
4.8.8.2 Request Status ..........................................102 ..........................................110
5 iCalendar Object Examples..........................................103 Examples..........................................111
6 Recommended Practices..............................................107 Practices..............................................115
7 Registration of Content Type Elements..............................107 Elements..............................116
7.1 Registration of New and Modified iCalendar Object Methods ......107 ......116
7.2 Registration of New Properties .................................108

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7.2.1 Define the property .........................................108 .........................................116
7.2.2 Post the Property definition ................................109 ................................117
7.2.3 Allow a comment period ......................................109 ......................................117
7.2.4 Submit the property for approval ............................109 ............................117
7.3 Property Change Control ........................................109 ........................................118
8 References.........................................................109 References.........................................................118
9 Acknowledgments....................................................111 Acknowledgments....................................................120
10 Author's Address..................................................111 Address..................................................120
11 Full Copyright Statement..........................................112 Statement..........................................121

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1 Introduction

The use of calendaring and scheduling has grown considerably in the
last decade. Enterprise and inter-enterprise business has become
dependent on rapid scheduling of events and actions using this
information technology. However, the longer term growth of
calendaring and scheduling, is currently limited by the lack of
Internet standards for the message content types that are central to
these knowledgeware applications. This memo is intended to progress
the level of interoperability possible between dissimilar calendaring
and scheduling applications. This memo defines a MIME content type
for exchanging electronic calendaring and scheduling information. The
Internet Calendaring and Scheduling Core Object Specification, or
iCalendar, allows for the capture and exchange of information
normally stored within a calendaring and scheduling application; such
as a Personal Information Manager (PIM) or a Group Scheduling
product.

The calendaring and scheduling model, defined in the [ICMS], is a
useful reference to terms and the general framework of this Internet
application.

The iCalendar format is suitable as an exchange format between
applications or systems. The format is defined in terms of a MIME
content type. This will enable the object to be exchanged using
several transports, including but not limited to SMTP, HTTP, a file
system, desktop interactive protocols such as the use of a memory-
based clipboard or drag/drop interactions, point-to-point
asynchronous communication, wired-network transport, or some form of
unwired transport such as infrared might also be used.

The memo also provides for the definition of iCalendar object methods
that will map this content type to a set of messages for supporting
calendaring and scheduling operations such as requesting, replying
to, modifying, and canceling meetings or appointments, to-dos and
journal entries. The iCalendar object methods can be used to define
other calendaring and scheduling operations such a requesting for and
replying with free/busy time data. Such a scheduling protocol is
defined in the iCalendar Transport-independent Interoperability
Protocol (iTIP) defined in [ITIP].

The memo also includes a formal grammar for the content type based on
the Internet ABNF defined in [RFC 2234]. This ABNF is required for
the implementation of parsers and to serve as the definitive
reference when ambiguities or questions arise in interpreting the
descriptive prose definition of the memo.

2 Basic Grammar and Conventions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY" and

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"OPTIONAL" in this document are to be interoperated as described in
[RFC 2119].

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This memo makes use of both a descriptive prose and a more formal
notation for defining the calendaring and scheduling format.

The notation used in this memo is the ABNF notation of [RFC 2234].
Readers intending on implementing this format defined in this memo
should be familiar with this notation in order to properly interpret
the specifications of this memo.

All numeric and hexadecimal values used in this memo are given in
decimal notation.

All names of properties, property parameters, enumerated property
values and property parameter values are case-
insensitive. case-insensitive. However,
all other property values are case-sensitive, unless otherwise
stated.

Note: All indented editorial notes, such as this one, are
intended to provide the reader with additional information. The
information that is not essential to the building of a conformant an
implementation
of the specifications of conformant with this memo. The information is
provided to highlight a particular feature or characteristic of
the
specifications. memo.

The format for the iCalendar object is based on the syntax of the
[MIME DIR] content type. While the iCalendar object is not a profile
of the [MIME DIR] content type, it does reuse a number of the
elements from the [MIME DIR] specification.

2.1 Formatting Conventions

The mechanisms defined in this memo are defined in propose. prose. Many of the
terms used to describe these have common usage that is different than
the standards usage of this memo. In order to reference within this
memo elements of the calendaring and scheduling model [ICMS], core
object (this memo) or interoperability protocol [ITIP] some
formatting conventions have been used. Calendaring and scheduling
roles defined by [ICMS] are referred to in quoted-strings of text
with the first character of each word in upper case. For example,
"Organizer" refers to a role of a "Calendar User" within the
scheduling protocol defined by [ITIP] [ITIP]. Calendar components defined by
this memo are referred to with capitalized, quoted-strings of text.
All calendar components start with the letter "V". For example,
"VEVENT" refers to the event calendar component, "VTODO" refers to
the to-do calendar component and "VJOURNAL" refers to the daily
journal calendar component. Scheduling methods defined by [ITIP] are
referred to with capitalized, quoted-strings of text. For example,
"REQUEST" refers to the method for requesting a scheduling calendar
component be created or modified, "REPLY" refers to the method a
recipient of a request uses to update their status with the
"Organizer" of the calendar component.

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The properties defined by this memo are referred to with capitalized,
quoted-strings of text, followed by the word "property". For example,
"ATTENDEE" property refers to the iCalendar property used to convey
the calendar address of a calendar user. Property parameters defined
by this memo are referred to with lower case, lowercase, quoted-strings of text,

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followed by the word "parameter". For example, "value" parameter
refers to the iCalendar property parameter used to override the
default data type for a property value. Enumerated values defined by
this memo are referred to with capitalized text, either alone or
followed by the word "value". For example, the "MINUTELY" value can
be used with the "FREQ" component of the "RECUR" data type to specify
repeating components based on an interval of one minute or more.

2.2 Related Memos

Implementers will need to be familiar with several other memos that,
along with this memo, form a framework for Internet calendaring and
scheduling standards. This memo, [ICAL], specifies a core
specification of objects, data types, properties and property
parameters.

[ICMS] - specifies a common terminology and abstract model;

[ITIP] - specifies an interoperability protocol for scheduling
between different implementations;

[IMIP] specifies an Internet email binding for [ITIP];

[IRIP] - specifies an Internet real time protocol binding for [ITIP].

This memo does not attempt to repeat the specification of concepts or
definitions from these other memos. Where possible, references are
made to the memo that provides for the specification of these
concepts or definitions.

3 TEXT/CALENDAR Registration Information

The Calendaring and Scheduling Core Object Specification is intended
for use as a

2.3 International Considerations

In the rest of this document, descriptions of characters are of the
form "character name (codepoint)", where "codepoint" is from the US-
ASCII character set. The "character name" is the authoritative
description; (codepoint) is a reference to that character in US-
ASCII or US-ASCII compatible sets (for example the ISO-8859-x family,
UTF-8, ISO-2022-xx, KOI8-R). If a non-US-ASCII compatible character
set is used, appropriate code-point from that character set must be
chosen instead. Use of non-US-ASCII-compatible character sets is NOT
recommended.

3 Registration Information

The Calendaring and Scheduling Core Object Specification is intended
for use as a MIME content type. However, the implementation of the
memo is in no way limited solely as a MIME content type.

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3.1 Content Type

The following text is intended to register this memo as the MIME
content type "text/calendar".

To: ietf-types@uninett.no

Subject: Registration of MIME content type text/calendar.

MIME media type name: text

MIME subtype name: calendar

3.2 Parameters

Required parameters: none

Optional parameters: charset, method and method, component and optinfo

The "charset" parameter is defined in [RFC 2046] for other body
parts. It is used to identify the default character set used within
the body part.

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The "method" parameter is used to convey the iCalendar object method
or transaction semantics for the calendaring and scheduling
information. It also is an identifier for the restricted set of
properties and values that the iCalendar object consists of. The
parameter is to be used as a guide for applications interpreting the
information contained within the body part. It SHOULD NOT be used to
exclude or require particular pieces of information unless the
identified method definition specifically calls for this behavior.
Unless specifically forbidden by a particular method definition, a
text/calendar content type MAY can contain any set of properties
permitted by the Calendaring and Scheduling Core Object
Specification. The "method" parameter MUST be the same value as that
specified in the "METHOD" component property in the iCalendar object.
If one is present, the other must also be present.

The value for the "method" parameter is defined as follows:

method = 1*(ALPHA / DIGIT / "-")
; IANA registered iCalendar object method

The "component" parameter conveys the type of iCalendar calendar
component within the body part. If the iCalendar object contains more
than one calendar component, component type, then different components are
each specified once in a comma-separated list of values. multiple component parameters
MUST be specified.

The value for the "component" parameter is defined as follows:

component = ("VEVENT" / "VTODO" / "VJOURNAL" / "VFREEBUSY"
/ "VTIMEZONE" / x-name / iana-token) ["," [WSP]
component]

Optional content header fields: Any header fields defined by [RFC
2045].

Encoding considerations:

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The "optinfo" parameter conveys optional information about the
iCalendar object within the body part. This MIME content type parameter can contain 8bit
characters, so only
specify semantics already specified by the use of quoted-printable or base64 MIME content-
transfer-encodings MAY iCalendar object and that
can be necessary when otherwise determined by parsing the body part. In addition,
the optional information specified by this parameter MUST be
consistent with that information specified by the iCalendar objects are
transferred across protocols restricted object.
For example, it can be used to convey the 7bit repertoire.
Note that "Attendee" response status
to a text valued property in the content entity MAY also
have content encoding meeting request. The parameter value consists of special characters using a string value.
The parameter can be specified multiple times.

This parameter MAY only specify semantics already specified by the
iCalendar object and that can be otherwise determined by parsing the
body part.

The value for the "optinfo" parameter is defined as follows:

optinfo = infovalue / qinfovalue

infovalue = iana-token / x-name

qinfovalue = DQUOTE (infovalue) DQUOTE

3.3 Content Header Fields

Optional content header fields: Any header fields defined by [RFC
2045].

3.4 Encoding Considerations

This MIME content type can contain 8bit characters, so the use of
quoted-printable or BASE64 MIME content-transfer-encodings might be
necessary when iCalendar objects are transferred across protocols
restricted to the 7bit repertoire. Note that a text valued property
in the content entity can also have content encoding of special
characters using a BACKSLASH character (ASCII (US-ASCII decimal 92)
escapement technique. This means that content values MAY can end up
encoded twice.

3.5 Security considerations: Considerations

SPOOFING - - In this memo, the "Organizer" is the only person
authorized to make changes to an existing "VEVENT", "VTODO",
"VJOURNAL" calendar component and redistribute the updates to the
"Attendees". An iCalendar object that maliciously changes or cancels
an existing "VEVENT", "VTODO" or "VJOURNAL" or "VFREEBUSY" calendar
component MAY might be constructed by someone other than the "Organizer"
and sent to the "Attendees". In addition in this memo, other than the
"Organizer", an "Attendee" of a "VEVENT", "VTODO", "VJOURNAL"
calendar component is the only other person authorized to update any
parameter associated with their "ATTENDEE" property and send it to
the "Organizer". An

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"ATTENDEE" parameters
MAY can be constructed by someone other than the
real "Attendee" and sent to the "Organizer".

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PROCEDURAL ALARMS - - An iCalendar object can be created that
contains a "VEVENT" and "VTODO" calendar component with an "VALARM"
calendar components. The "VALARM" calendar component MAY can be of type
PROCEDURE and MAY can have an attachment containing some sort of
executable program. Implementations that incorporate these types of
alarms are subject to any virus or malicious attack that MAY might occur
as a result of executing the attachment.

ATTACHMENTS - - An iCalendar object MAY can include references to Uniform
Resource Locators that MAY can be programmed resources.

Implementers and users of this memo should be aware of the network
security implications of accepting and parsing such information. In
addition, the security considerations observed by implementations of
electronic mail systems should be followed for this memo.

3.6 Interoperability considerations: Considerations

This MIME content type is intended to define a common format for
conveying calendaring and scheduling information between different
systems. It is heavily based on the earlier [VCAL] industry
specification.

3.7 Applications which use this media type: Which Use This Media Type

This content-type is designed for widespread use by Internet
calendaring and scheduling applications. In addition, applications in
the workflow and document management area may might find this content-type content-
type applicable. The
[ITIP], [IMIP] [ITIP] and [IRIP] [IMIP] Internet protocols directly
use this content-type also. Future work on an Internet calendar
access protocol will utilize this content-type too.

3.8 Additional information: Information

This memo defines this content-type.

3.9 Magic numbers: Numbers

None.

3.10 File extensions: Extensions

The file extension of "ics" is to be used to designate a file
containing an (an arbitrary set of of) calendaring and scheduling
information consistent with this MIME content type.

The file extension of "ifb" is to be used to designate a file
containing free or busy time information consistent with this MIME
content type.

Macintosh file type codes: The file type code of "ical" "iCal" is to be used
in Apple MacIntosh operating system environments to designate a file
containing calendaring and scheduling information consistent with
this MIME media type.

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The file type code of "ifb" "iFBf" is to be used in Apple MacIntosh
operating system environments to designate a file containing free or
busy time information consistent with this MIME media type.

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Person & email address to contact

3.11 Contact for further information: Further Information:

Frank Dawson
6544 Battleford Drive
Raleigh, NC 27613-3502
919-676-9515 (Telephone)
919-676-9564 (Data/Facsimile)
Frank_Dawson@Lotus.com (Internet Mail)

Derik Stenerson
One Microsoft Way
Redmond, WA 98052-6399
425-936-5522 (Telephone)
425-936-7329 (Facsimile)
deriks@microsoft.com (Internet Mail)

3.12 Intended usage: Usage

COMMON

Author/change controller:

3.13 Authors/Change Controllers

Frank Dawson
6544 Battleford Drive
Raleigh, NC 27613-3502
919-676-9515 (Telephone)
919-676-9564 (Data/Facsimile)
Frank_Dawson@Lotus.com (Internet Mail)

Derik Stenerson
One Microsoft Way
Redmond, WA 98052-6399
425-936-5522 (Telephone)
425-936-7329 (Facsimile)
deriks@microsoft.com (Internet Mail)

4 iCalendar Object Specification

The following sections define the details of a Calendaring and
Scheduling Core Object Specification. This information is intended to
be an integral part of the MIME content type registration. In
addition, this information MAY can be used independent of such content
registration. In particular, this memo has direct applicability for
use as a calendaring and scheduling exchange format in file-, memory-
or network-based transport mechanisms.

4.1 Content Lines

The iCalendar object is organized into individual lines of text,
called content lines. Content lines are delimited by a line break,

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which is a CRLF sequence (ASCII (US-ASCII decimal 13, followed by ASCII US-ASCII
decimal 10).

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Lines of text SHOULD NOT be longer than 75 characters, octets, excluding the line
break. Long content lines SHOULD be split into a multiple line
representations using a line "folding" technique. That is, a long
line MAY can be split at between any point two characters by inserting a CRLF
immediately followed by a single linear white space character (i.e.,
SPACE, ASCII US-ASCII decimal 32 or HTAB, ASCII US-ASCII decimal 9). Any sequence
of CRLF followed immediately by a single linear white space character
is ignored (i.e., removed) when processing the content type.

For example the line:

DESCRIPTION:This is a long description that exists on a long line.

Can be represented as:

DESCRIPTION:This is a lo
ng description
that exists on a long line.

The process of moving from this folded multiple line representation
to its single line representation is called "unfolding". Unfolding is
accomplished by removing the CRLF character and the linear white
space character that immediately follows.

When parsing a content line, folded lines must first be unfolded
according to the unfolding procedure described above. When generating
a content line, lines longer than 75 characters octets SHOULD be folded
according to the folding procedure described above.

The content information associated with an iCalendar object is
formatted using a syntax similar to that defined by [MIME DIR]. That
is, the content information consists of one or more CRLF-separated
content lines.

The following notation defines the defines the lines of content in an
iCalendar object:

contentline = name *(";" [WSP] param ) ":" value CRLF
; This ABNF is just a general definition for an initial parsing
; of the content line into its property name, parameter list,
; and value string

; When parsing a content line, folded lines must first
; be unfolded according to the unfolding procedure
; described above. When generating a content line, lines
; longer than 75 characters octets SHOULD be folded according to
; the folding procedure described above.

name = x-name / iana-token

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iana-token = 1*(ALPHA / DIGIT / "-")
; iCalendar identifier registered with IANA

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x-name = "X-" [vendorid "-"] 1*(ALPHA / DIGIT / "-")
; Reservered for experimental use. Not intended for use in
; released products.

vendorid = 3*(ALPHA / DIGIT) ;Vendor identification

param = param-name "=" param-value
*("," param-value)
; Each property defines the specific ABNF for the parameters
; allowed on the property. Refer to specific properties for
; precise parameter ABNF.

param-name = iana-token / x-token

param-value = paramtext / quoted-string

paramtext = *SAFE-CHAR

value = *VALUE-CHAR

quoted-string = DQUOTE *qtext *QSAFE-CHAR DQUOTE

qtext = QSAFE-CHAR / QUOTED-CHAR

NON-ASCII

NON-US-ASCII = %x80-FF %x80-F8
; Use restricted by charset parameter
; on outer MIME object (UTF-8 preferred)

QSAFE-CHAR = WSP / %x21 / %x23-5B / %x5D-7E %x23-7E / NON-ASCII NON-US-ASCII
; Any character except CTLs, DQUOTE, or "\"

QUOTED-CHAR = "\" ("\" / "," / DQUOTE)
; \\ encodes \, \" encodes " CTLs and DQUOTE

SAFE-CHAR = WSP / %x21 / %x23-2B / %x2D-39 / %x3C-7E
/ NON-ASCII NON-US-ASCII
; Any character except CTLs, DQUOTE, ";", ":", ","

VALUE-CHAR = WSP / VCHAR %x21-7E / NON-ASCII NON-US-ASCII
; Any textual character

VCHAR = %x21-7E
; visible (printing) characters

CR = %x0D
; carriage return

LF = %x0A
; line feed

CRLF = CR LF
; Internet standard newline

CTL = %x00-1F %x00-08 / %x0A-1F / %x7F
; Controls

ALPHA = %x41-5A / %x61-7A ; A-Z / a-z

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DIGIT = %x30-39
; 0-9

DQUOTE = %x22
; Quotation Mark

WSP = SPACE / HTAB

SPACE = %x20

HTAB = %x09

The property value component of a content line has a format that is
property specific. Refer to the section describing each property for
a definition of this format.

All names of properties, property parameters, enumerated property
values and property parameter values are case-insensitive. However,
all other property values are case-sensitive, unless otherwise
stated.

4.1.1 List and Field Separators

List

Some properties and parameters allow a list of values MAY be specified for property values or property
parameter values. Each value in
a list of values MUST be separated by a COMMA character (ASCII (US-ASCII
decimal 44). There is no significance to the ordering of values in a
list. For those parameter values (such as those that specify URI
values) that are specified in quoted-strings, the individual quoted-
strings are separated by a COMMA character (US-ASCII decimal 44).

Some property values are defined in terms of multiple components. parts. These
structured property values MUST have their components value parts separated by a
SEMICOLON character (ASCII (US-ASCII decimal 59).

Lists of property parameters MAY be specified for

Some properties allow a property. list of parameters. Each property parameter
in a list of property parameters MUST be separated by a SEMICOLON
character (ASCII (US-ASCII decimal 59).

Property parameters with values containing a COLON, a SEMICOLON or a
COMMA character must MUST be placed in quoted text string. text.

For example, in the following properties a SEMICOLON is used to
separate property parameters and property value fields. A COMMA is
used to separate values.

ATTENDEE;RSVP=TRUE;ROLE=REQ-PARTICIPANT:MAILTO:
jsmith@host.com

RDATE;VALUE=DATE:19970304,19970504,19970704,19970904

4.1.2 Multiple Values

Some properties defined in the iCalendar object MAY can have multiple
values. The general rule for encoding multi-valued items is to simply

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create a new content line for each value; value, including the property
name. However, it should be noted that some properties support
encoding multiple values in a single property by separating the
values with a COMMA character (ASCII (US-ASCII decimal 44).

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property definitions should be consulted for determining whether a
specific property allows multiple values and in which of these two
forms.

4.1.3 Binary Content

Binary content information in an iCalendar object SHOULD be
referenced using a URI within a property value. That is the binary
content information SHOULD be placed in an external MIME entity that
can be referenced by a URI from within the iCalendar object. In
applications where this is not feasible, binary content information
MAY
can be included within an iCalendar object, but only after first
encoding it into text using the "B" "BASE64" encoding method defined in
[RFC
2047]. 2045]. Support for inline binary content SHOULD be restricted to
those applications requirements that necessitate conveying the
complete calendaring and scheduling information within a single
iCalendar object. A property containing inline binary content
information MUST specify the "ENCODING" property parameter. Binary
content information placed external to the iCalendar object MUST be
referenced by a uniform resource identifier (URI).

The following example specifies an "ATTACH" property that references
an attachment external to the iCalendar object with a URI reference:

ATTACH:http://xyz.com/public/quarterly-report.doc

The following example specifies an "ATTACH" property with inline
binary encoded content information:

ATTACH;ENCODING=b;VALUE=binary:MIICajCCAdOgAwIBAgICBEUwDQYJKoZI
hvcNAQEEBQAwdzELMAkGA1UEBhMCVVMxLDAqBgNVBAoTI05ldHNjYXBlIENv
bW11bmljYXRpb25zIENvcnBvcmF0aW9uMRwwGgYDVQQLExNJbmZvcm1hdGlv
biBTeXN0

ATTACH;ENCODING=BASE64;VALUE=BINARY:MIICajCCAdOgAwIBAgICBEUwD
QYJKoZIhvcNAQEEBQAwdzELMAkGA1UEBhMCVVMxLDAqBgNVBAoTI05ldHNjY
XBlIENvbW11bmljYXRpb25zIENvcnBvcmF0aW9uMRwwGgYDVQQLExNJbmZvc
<...remainder of "B" "BASE64" encoded binary data...>

4.1.4 Character Set

There is not a property parameter to declare the character set used
in a property value. The default character set for an iCalendar
object is [UTF-8]. UTF-8 as defined in [RFC 2279].

The "charset" Content-Type parameter MAY can be used in MIME transports
to specify any other IANA registered character set.

4.2 Property Parameters

A property MAY can have additional attributes associated with it. These "property
parameters" contain meta information meta-information about the property or the
property value. Property parameters MAY be used are provided to specify such
information as the location of an alternate text representation for a property value,
the language of a text property value or

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property value, the language of a text property value, the data type
of the property value. In addition, individual properties MAY define
property-specific parameters that apply only to that property. value and other attributes.

Property parameter values that contain the COLON, SEMICOLON, COMMA COLON (US-ASCII decimal
58), SEMICOLON (US-ASCII decimal 59) or
BACKSLASH COMMA (US-ASCII decimal 44)
character separators MUST be specified as quoted-string text values.
Property parameter values MUST NOT contain the DOUBLE-QUOTE (US-ASCII
decimal 22) character. The DOUBLE-QUOTE (US-ASCII decimal 22)
character is used as a delimiter for parameter values that contain
restricted characters or URI text. For example:

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DESCRIPTION;ALTREP="http://www.wiz.org":The Fall'98 Wild Wizards
Conference - - Las Vegas, NV, USA

Property parameter values that are not in quoted strings are case
insensitive.

The general property parameters defined by this memo are specified defined by
the following notation:

parameter = altrepparm ;Alternate altrepparam ; Alternate text representation
/ encodingparm ;Inline cnparam ; Common name
/ cutypeparam ; Calendar user type
/ delfromparam ; Delegator
/ deltoparam ; Delegatee
/ dirparam ; Directory entry
/ encodingparam ; Inline encoding
/ languageparm ;National language fbtypeparam ; Free/busy time type
/ languageparam ; Language for text
/ tzidparm ;Reference memberparam ; Group or list membership
/ partstatparam ; Participation status
/ rangeparam ; Recurrence identifier range
/ trigrelparam ; Alarm trigger relationship
/ reltypeparam ; Relationship type
/ roleparam ; Participation role
/ rsvpparam ; RSVP expectation
/ sentbyparam ; Sent by
/ tzidparam ; Reference to time zone object
/ valuetypeparm ;Property valuetypeparam ; Property value data type
/ iana-token
;Some ianaparam
; Some other IANA registered iCalendar parameter, such as those
;defined by an individual property. parameter.
/ x-name
;A xparam
; A non-standard, experimental parameter parameter.

ianaparam = iana-token "=" param-value *("," param-value)

xparam =x-name "=" param-value *("," param-value)

4.2.1 Alternate Text Representation

Parameter Name: ALTREP

Purpose: To specify an alternate text representation for the property
value.

Conformance: Optional

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Format Definition: The property parameter is defined by the following
notation:

altrepparm

altrepparam = "altrep" "ALTREP" "=" DQUOTE uri DQUOTE

Description: The parameter specifies a URI that points to an
alternate representation for a textual property value. A property
specifying this parameter MUST also include a value that reflects the
default representation.

This property parameter MAY include multiple values, separated by representation of the
COMMA character (ASCII decimal 44). text value. The property individual URI
parameter MAY only values MUST be specified in the "COMMENT", "CONTACT", "DESCRIPTION", "LOCATION"
and "SUMMARY" properties. a quoted-string.

Example:

DESCRIPTION;ALTREP="CID:<part3.msg.970415T083000@host.com>":Project
XYZ Review Meeting will include the following agenda items: (a)
Market Overview, (b) Finances, (c) Project Management

The "ALTREP" property parameter value might point to a "text/html"
content portion.

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Content-Type:text/html
Content-Id:<part3.msg.970415T083000@host.com>

<html><body>
<p><b>Project XYZ Review Meeting</b> will include the following
agenda items:<li>Market
Overview</li><li>Finances</li><li>Project Management</li></p>
</html></body>

4.2.2 Inline Encoding Common Name

Parameter Name: ENCODING CN

Purpose: To specify an alternate inline encoding for the property
value.

Conformance: Required, if common name to be associated with the inline encoding is not "8bit".
calendar user specified by the property.

Format Definition: The property parameter is defined by the following
notation:

encodingparm

cnparam = "encoding" "CN" "=" "8bit"
;"8bit" text encoding is defined in [RFC 2045]
/ "b"
;"b" binary encoding format is defined in [RFC 2047]
/ iana-token
;Some other IANA registered iCalendar encoding type
/ x-name
;A non-standard, experimental encoding type param-value

Description: The "ENCODING property This parameter is an OPTIONAL property
parameter. It identifies the inline encoding used in a property
value. The default encoding type is "8bit", corresponding to can be specified on properties with a
property
CAL-ADDRESS value consisting of text. type. The "b" encoding type corresponds
to a property value encoded using the "B" encoding defined in [RFC
2047].

If the value type parameter is ";VALUE=BINARY", then specifies the inline
encoding parameter MUST common name to be specified
associated with the value ";ENCODING=B".

4.2.3 Language

Parameter Name: LANGUAGE

Purpose: To specify calendar user specified by the national language for text values in a
property or property parameter.

Conformance: Optional. There is no default national language for a
text value.

Format Definition: property. The property
parameter value is defined text. The parameter value can be used for display
text to be associated with the calendar address specified by the following
notation:

languageparm = "language" "=" language

language = <Text identifying a language, as defined in [RFC 1766]>
property.

Example:

ORGANIZER;CN="John Smith":MAILTO:jsmith@host.com

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Description: The parameter identifies

4.2.3 Calendar User Type

Parameter Name: CUTYPE

Purpose: To specify the national language type of calendar user specified by the
text in the property or property parameter value.
property.

Format Definition: The value of the
"language" property parameter is that defined in [RFC 1766].

Note: For transport in a MIME entity, the Content-Language
header field MAY be used to set by the default language for following
notation:

cutypeparam = "CUTYPE" "="
("INDIVIDUAL" ; An individual
/ "GROUP" ; A group of individuals
/ "RESOURCE" ; A physical resource
/ "ROOM" ; A room resource
/ "UNKNOWN" ; Otherwise not known
/ x-name ; Experimental type
/ iana-token) ; Other IANA registered
; type
; Default is INDIVIDUAL

Description: This parameter can be specified on properties with a
CAL-ADDRESS value type. The parameter identifies the
entire body part. type of calendar
user specified by the property. If not specified on a property that
allows this parameter, the default is INDIVIDUAL.

Example:

SUMMARY;LANGUAGE=us-EN:Company Holiday Party

ATTENDEE;CN=Henri Weisz;LANGUAGE=ca-FR:hweisz@host.com

ATTENDEE;CUTYPE=GROUP:MAILTO:ietf-calsch@imc.org

4.2.4 Time Zone Identifier Delegators

Parameter Name: TZID DELEGATED-FROM

Purpose: To specify the identifier for calendar users that have delegated their
participation to the time zone definition for a
time value.

Conformance: Optional calendar user specified by the property.

Format Definition: This The property parameter is defined by the following
notation:

tzidparm

delfromparam = "TZID" "DELEGATED-FROM" "=" [tzidprefix] paramtext CRLF

tzidprefix = "/" DQUOTE cal-address DQUOTE
*("," DQUOTE cal-address DQUOTE)

Description: The This parameter MAY only can be used specified on the "DTSTART",
"DTEND", "DUE", "EXDATE" and "RDATE " properties when either with a DATE-
TIME or TIME
CAL-ADDRESS value type is specified. type. This property parameter
specifies can be specified on a property
that has a text value which uniquely identifies the "VTIMEZONE" type of calendar component address. This parameter specifies
those calendar uses that have delegated their participation in a
group scheduled event or to-do to be used when evalating the time portion of calendar user specified by the
property. The value of the TZID property parameter will MUST be equal to
the value of the TZID property for the matching "TIMEZONE" object.
The presence of the SOLIDUS character (ASCII decimal 47) as a prefix,
indicates that this TZID represents a unique ID in a globally MAILTO URI as defined
time zone registry (when such registry is defined).

The following are examples of this property parameter:

DTSTART;TZID=America-New_York:19980119T020000

DTEND;TZID=America-New_York:19980119T030000 in [RFC 1738].
The TZID property individual URI parameter values MUST NOT be applied to DATE-TIME nor TIME
properties whose time values are specified in UTC.

The use of local time in a DATE-TIME or TIME value without the TZID
property parameter is to be interpreted as a local time value,
regardless of the existence of "VTIMEZONE" calendar components in the
iCalendar object. quoted-
string.

Example:

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For more information see the sections on the data types DATE-TIME and
TIME.

ATTENDEE;DELEGATED-FROM="MAILTO:jsmith@host.com":MAILTO:
jdoe@host.com

4.2.5 Value Data Types Delegatees

Parameter Name: VALUE DELEGATED-TO

Purpose: To explicitly specify the data type format for a property
value.

Conformance: Optional if using calendar users whom the calendar user
specified by the default value type in a property
value. Otherwise, it is required. has delegated participation to.

Format Definition: The "VALUE" property parameter is defined by the following
notation:

valuetypeparm

deltoparam = "value" "DELEGATED-TO" "=" valuetype

valuetype = "binary"
/ "boolean"
/ "cal-address"
/ "date"
/ "date-time"
/ "duration"
/ "float"
/ "integer"
/ "period"
/ "recur"
/ "text"
/ "time"
/ "uri"
/ "utc-offset"
/ x-name
;Some experimental iCalendar data type.
/ iana-token
;Some other IANA registered iCalendar data type. DQUOTE cal-address DQUOTE
*("," DQUOTE cal-address DQUOTE)

Description: The This parameter is used to identify the data type and
format of the property value. The property values MUST can be of specified on properties with a single
CAL-ADDRESS value type. For example, a "RDATE" property cannot This parameter specifies those calendar users
whom have been delegated participation in a combination
of DATE-TIME and TIME value types.

4.3 Property Value Data Types group scheduled event or
to-do by the calendar user specified by the property. The properties in an iCalendar object are strongly typed. The
definition of each property restricts the value to MUST
be one of the
value data types, or simply value types, a MAILTO URI as defined in this section. [RFC 1738]. The
value type for a property will either individual URI
parameter values MUST be specified implicitly as in a quoted-string.

Example:

ATTENDEE;DELEGATED-TO="MAILTO:jdoe@host.com","MAILTO:jqpublic@
host.com":MAILTO:jsmith@host.com

4.2.6 Directory Entry Reference

Parameter Name: DIR

Purpose: To specify reference to a directory entry associated with
the
default value type or will calendar user specified by the property.

Format Definition: The property parameter is defined by the following
notation:

dirparam = "DIR" "=" DQUOTE uri DQUOTE

Description: This parameter can be explicitly specified on properties with a
CAL-ADDRESS value type. The parameter specifies a reference to the
directory entry associated with the "VALUE"
parameter. If calendar user specified by the
property. The parameter value type of a property is one of the alternate
valid types, then it a URI. The individual URI parameter
values MUST be explicitly specified with the "VALUE"
parameter. in a quoted-string.

Example:

ORGANIZER;DIR="ldap://host.com:6666/o=eDABC%20Industries,c=3DUS??
(cn=3DBJim%20Dolittle)":MAILTO:jimdo@host1.com

4.2.7 Inline Encoding

Parameter Name: ENCODING

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4.3.1 Binary

Value Name: BINARY

Purpose: This value type is used to identify properties that contain
a character encoding of inline binary data. For example, To specify an alternate inline
attachment of an object code MAY BE included in an iCalendar object.

Formal encoding for the property
value.

Format Definition: The value type property parameter is defined by the following
notation:

binary

encodingparam = *(4b-char) [b-end] "ENCODING" "="
("8BIT"
; A "B" encoded character string, as "8bit" text encoding is defined by in [RFC 2047].

b-end = (2b-char "==") / (3b-char "=")

b-char = ALPHA 2045]
/ DIGIT "BASE64"
; "BASE64" binary encoding format is defined in [RFC 2045]
/ "+" iana-token
; Some other IANA registered iCalendar encoding type
/ "/"

Description: Property values with this value x-name)
; A non-standard, experimental encoding type MUST also include

Description: The property parameter identifies the inline encoding parameter sequence
used in a property value. The default encoding is "8BIT",
corresponding to a property value consisting of ";ENCODING=B". That is, all
inline binary data MUST first be character text. The "BASE64"
encoding type corresponds to a property value encoded using the "B"
"BASE64" encoding method defined in [RFC 2047]. No additional content 2045].

If the value
encoding (i.e., BACKSLASH character encoding) type parameter is defined for this ";VALUE=BINARY", then the inline
encoding parameter MUST be specified with the value type.
";ENCODING=BASE64".

Example: The following is an abridged example of a "B" encoded binary
value data.

ATTACH;VALUE=BINARY:MIICajCCAdOgAwIBAgICBEUwDQYJKoZIhvcNAQEEBQA
wdzELMAkGA1UEBhMCVVMxLDAqBgNVBAoTI05ldHNjYXBlIENvbW11bmljYXRpb
25zIENvcnBvcmF0aW9uMRwwGgYDVQQLExNJbmZvcm1hdGlvbiBTeXN0

4.3.2 Boolean

Value

4.2.8 Free/Busy Time Type

Parameter Name: BOOLEAN FBTYPE

Purpose: This value type is used to identify properties that contain
either a "true" To specify the free or "false" boolean value.

Formal busy time type.

Format Definition: The value type property parameter is defind defined by the following
notation:

boolean

fbtypeparam = "TRUE" "FBTYPE" "=" ("FREE" / "FALSE" "BUSY"
/ "BUSY-UNAVAILABLE" / "BUSY-TENTATIVE"
/ x-name
; Some experimental iCalendar data type.
/ iana-token)
; Some other IANA registered iCalendar data type.

Description: These values are case insensitive text. No additional
content The parameter specifies the free or busy time type. The
value encoding (i.e., BACKSLASH character encoding) FREE indicates that the time interval is
defined free for this scheduling.
The value type.

Example: For example, any of BUSY indicates that the time interval is busy because one
or more events have been scheduled for that interval. The value BUSY-
UNAVAILABLE indicates that the time interval is busy and that the following are equivalent:

TRANSP;VALUE=BOOLEAN:TRUE
TRANSP;VALUE=BOOLEAN:true
TRANSP;VALUE=BOOLEAN:TrUe

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4.3.3 Calendar User Address

Value Name: CAL-ADDRESS

Purpose: This

interval can not be scheduled. The value type is used to identify properties BUSY-TENTATIVE indicates
that contain
a calendar user address.

Formal Definition: The value type is as defined by the following
notation:

cal-address = uri

Description: The value time interval is a URI as defined by [RFC 1738] busy because one or any other
IANA registered form for a URI. When used to address an Internet
email transport address more events have been
tentatively scheduled for that interval. If not specified on a calendar user,
property that allows this parameter, the value MUST be a
MAILTO URI, as defined by [RFC 1738].No additional content value
encoding (i.e., BACKSLASH character encoding) default is defined for this
value type. BUSY.

Example:

ATTENDEE;VALUE=CAL-ADDRESS:MAILTO:jane_doe@host.com

4.3.4 Date

Value The following is an example of this parameter on a FREEBUSY
property.

FREEBUSY;FBTYPE=BUSY:19980415T133000Z/19980415T170000Z

4.2.9 Language

Parameter Name: DATE LANGUAGE

Purpose: This value type is used to identify To specify the language for text values that contain in a
calendar date.

Formal property or
property parameter.

Format Definition: The value type property parameter is defined by the following
notation:

date = date-value *("," [WSP] date-value)

date-value = date-fullyear date-month date-mday
date-fullyear

languageparam = 4DIGIT
date-month = 2DIGIT ;01-12
date-mday "LANGUAGE" "=" language

language = 2DIGIT ;01-28, 01-29, 01-30, 01-31
;based on month/year <Text identifying a language, as defined in [RFC 1766]>

Description: If the property permits, multiple "date" values MAY This parameter can be specified using on properties with a COMMA character (ASCII decimal 44) separator
character.The format for the
text value type is expressed as the [ISO
8601] complete representation, basic format for a calendar date. type. The
textual format specifies a four-digit year, two-digit month, and two-
digit day parameter identifies the language of the month. There are no separator characters between text in
the
year, month and day component text.

No additional content property or property parameter value. The value encoding (i.e., BACKSLASH character
encoding) of the "language"
property parameter is that defined in [RFC 1766].

For transport in a MIME entity, the Content-Language header field can
be used to set the default language for this value type. the entire body part.
Otherwise, no default language is assumed.

Example:

SUMMARY;LANGUAGE=us-EN:Company Holiday Party

LOCATION;LANGUAGE=en:Germany
LOCATION;LANGUAGE=no:Tyskland

The following represents July 14, 1997: example makes use of the Quoted-Printable encoding in
order to represent non-ASCII characters.

LOCATION;LANGUAGE=da:K=F8benhavn
LOCATION;LANGUAGE=en:Copenhagen

4.2.10 Group or List Membership

Parameter Name: MEMBER

Purpose: To specify the group or list membership of the calendar user
specified by the property.

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4.3.5 Date-Time

Value Name: DATE-TIME

Purpose: This value type is used to identify values that specify a
precise calendar data and time of day.

Formal

Format Definition: The value type property parameter is defined by the following
notation:

date-time

memberparam = dt-value "MEMBER" "=" DQUOTE cal-address DQUOTE
*("," [WSP] dt-value)

dt-value = date "T" time ;As specified above in date and time DQUOTE cal-address DQUOTE)

Description: If the property permits, multiple "date-time" values MAY This parameter can be specified using on properties with a COMMA character (ASCII decimal 44) separator
character. No additional content value encoding (i.e., BACKSLASH
character encoding) is defined for this
CAL-ADDRESS value type. The "DATE-TIME" data type is used to identify values that contain a
precise calendar date and time of day. The format is based on parameter identifies the
[ISO 8601] complete representation, basic format groups or list
membership for a calendar date
and time of day. The text format is a concatenation of the "date",
followed by the LATIN CAPITAL LETTER T character (ASCII decimal 84)
time designator, followed calendar user specified by the "time" format. property. The "DATE-TIME" data type expresses time values
parameter value either a single calendar address in three forms:

The form of date and time with UTC offset MUST NOT be used. For
example, the following is not valid for a date-time value:

DTSTART:19980119T230000-0800

FORM #1: DATE WITH LOCAL TIME

The date with local time form is simply quoted-string
or a date-time value that does
not contain the UTC designator nor does it reference COMMA character (US-ASCII decimal 44) list of calendar
addresses, each in a time zone. For
example, the following represents Janurary 18, 1998, at 11 PM:

DTSTART:19980118T230000

Date-time quoted-string. The individual calendar address
parameter values of this type are said to MUST be "floating" and are not
bound to any time zone specified in particular. They are used to represent a quoted-string.

Example:

ATTENDEE;MEMBER="MAILTO:ietf-calsch@imc.org":MAILTO:jsmith@host.com

ATTENDEE;MEMBER="MAILTO:projectA@host.com","MAILTO:projectB@host.
com":MAILTO:janedoe@host.com

4.2.11 Participation Status

Parameter Name: PARTSTAT

Purpose: To specify the
same hour, minute, and second value regardless of which time zone is
currently being observed. For example, an event MAY be defined that
indicates that an individual will be busy from 11:00 AM to 1:00 PM
every day, no matter which timezone participation status for the person is in. In these cases,
a local time MAY be specified. calendar user
specified by the property.

Format Definition: The recipient of an iCalendar object
with a property value consisting of a local time, without any
relative time zone information, should interpret the value as being
fixed to whatever timezone the ATTENDEE parameter is in at any given moment.
This means that two ATTENDEEs may participate in defined by the same event at

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different UTC times; floating time should only be used where that is
reasonable behavior.

In most cases, following
notation:

partstatparam = "PARTSTAT" "="
("NEEDS-ACTION" ; Event needs action
/ "ACCEPTED" ; Event accepted
/ "DECLINED" ; Event declined
/ "TENTATIVE" ; Event tentatively
; accepted
/ "DELEGATED" ; Event delegated
/ x-name ; Experimental status
/ iana-token) ; Other IANA registered
; status
; These are the participation statuses for a fixed time "VEVENT". Default is desired. To properly communicate a
fixed time in a
; NEEDS-ACTION

partstatparam /= "PARTSTAT" "="
("NEEDS-ACTION" ; To-do needs action
/ "ACCEPTED" ; To-do accepted
/ "DECLINED" ; To-do declined
/ "TENTATIVE" ; To-do tentatively
; accepted
/ "DELEGATED" ; To-do delegated
/ "COMPLETED" ; To-do completed.
; COMPLETED property value, either UTC time or local time with
time zone reference MUST be specified.

The use of local time has
;date/time completed.

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/ "IN-PROCESS" ; To-do in a DATE-TIME value without process of
; being completed
/ x-name ; Experimental status
/ iana-token) ; Other IANA registered
; status
; These are the TZID property
parameter participation statuses for a "VTODO". Default is to be interpreted as
; NEEDS-ACTION

partstatparam /= "PARTSTAT" "="
("NEEDS-ACTION" ; Journal needs action
/ "ACCEPTED" ; Journal accepted
/ "DECLINED" ; Journal declined
/ x-name ; Experimental status
/ iana-token) ; Other IANA registered
; status
; These are the participation statuses for a local time value, regardless of "VJOURNAL". Default is
; NEEDS-ACTION

4.2.12 Recurrence Identifier Range

Parameter Name: RANGE

Purpose: To specify the existence effective range of "VTIMEZONE" calendar components in recurrence instances from
the iCalendar
object.

FORM #2: DATE WITH UTC TIME

The date with UTC time, or absolute time, instance specified by the recurrence identifier specified by the
property.

Format Definition: The property parameter is identified defined by a LATIN
CAPITAL LETTER Z suffix character (ASCII decimal 90), the UTC
designator, appended following
notation:

rangeparam = "RANGE" "=" ("THISANDPRIOR"
; To specify all instances prior to the time value. For example, recurrence identifier
/ "THISANDFUTURE")
; To specify the following
represents January 19, 1998, at 0700 UTC:

DTSTART:19980119T070000Z instance specified by the recurrence identifier
; and all subsequent recurrence instances

Description: The TZID property parameter MUST NOT can be applied to DATE-TIME
properties whose time values are specified in UTC.

FORM #3: DATE WITH LOCAL TIME AND TIME ZONE REFERENCE on a property that
specifies a recurrence identifier. The date and local time with reference to time zone information parameter specifies the
effective range of recurrence instances that is
identified specified by the use
property. The effective range is from the TZID property recurrence identified
specified by the property. If this parameter to reference is not specified an
allowed property, then the
appropriate time zone definition. TZID default range is discussed in detail in the
section on Time Zone. For example, single instance
specified by the following represents 2 AM in
New York on Janurary 19, 1998:

DTSTART;TZID=America-New_York:19980119T020000

Example: The following represents July 14, 1997, at 1:30 PM in New
York City in each recurrence identifier value of the three time formats, using the "DTSTART" property.

DTSTART:19970714T133000 ;Local time
DTSTART:19970714T153000Z ;UTC time
DTSTART;TZID=America-NYC:19970714T133000 ;Local time and time
; zone reference

4.3.6 Duration

Value Name: DURATION

Purpose: This The
parameter value type is used can be "THISANDPRIOR" to identify properties that contain indicate a duration of time.

Formal Definition: The value type is range defined by
the following
notation:

duration = dur-value *("," [WSP] dur-value) recurrence identified value of the property and all prior
instances. The parameter value can also be "THISANDFUTURE" to
indicate a range defined by the recurrence identifier and all
subsequent instances.

Example:

RECURRENCE-ID;RANGE=THISANDPRIOR:19980401T133000Z

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dur-value = (["+"] / "-") "P" (dur-date / dur-time / dur-week)

dur-date = (dur-day) [dur-time]
dur-time = "T" (dur-hour / dur-minute / dur-second)
dur-week = 1*DIGIT "W"

dur-hour = 1*DIGIT "H" [dur-minute]
dur-minute = 1*DIGIT "M" [dur-second]
dur-second = 1*DIGIT "S"
dur-day = 1*DIGIT "D"

Description: If

4.2.13 Alarm Trigger Relationship

Parameter Name: RELATED

Purpose: To specify the property permits, multiple "duration" values MAY
be specified using a COMMA character (ASCII decimal 44) separator
character.The format is expressed as relationship of the [ISO 8601] basic format for alarm trigger with
respect to the duration of time. The format can represent durations in terms of
years, months, days, hours, minutes, and seconds.

No additional content value encoding (i.e., BACKSLASH character
encoding) are defined for this value type.

Example: A duration of 15 days, 5 hours, 30 minutes and 20 seconds
would be:

P15DT5H30M20S

A duration start or end of 7 weeks would be:

P15DT5H30M20S

4.3.7 Float

Value Name: FLOAT

Purpose: This value type is used to identify properties that contain
a real value number value.

Formal the calendar component.

Format Definition: The value type property parameter is defined by the following
notation:

float = float-value *("," [WSP] float-value)

float-value

trigrelparam = (["+"] "RELATED" "="
("START" ; Trigger off of start
/ "-") 1*DIGIT ["." 1*DIGIT] "END") ; Trigger off of end

Description: If the property permits, multiple "float" values MAY The parameter can be specified using a COMMA character (ASCII decimal 44) separator
character.

No additional content value encoding (i.e., BACKSLASH character
encoding) is defined for this value type.

Example:

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1000000.0000001
1.333
-3.14

4.3.8 Integer

Value Name:INTEGER

Purpose: This value type is used to identify on properties that contain
specify an alarm trigger with a signed integer value.

Formal Definition: The DURATION value type is defined by type. The parameter
specifies whether the following
notation:

integer = integer-value *("," [WSP] integer-value)

integer-value = (["+"] / "-") *DIGIT

Description: If alarm will trigger relative to the property permits, multiple "integer" values MAY
be specified using a COMMA character (ASCII decimal 44) separator
character.The valid range for "integer" is -2147483648 start or end
of the calendar component. The parameter value START will set the
alarm to 2147483647.
If trigger off the sign is not specified, then start of the calendar component; the
parameter value is assumed END will set the alarm to be
positive. trigger off the end of the
calendar component. If the property permits, multiple "integer" values MAY be parameter is not specified using a COMMA character (ASCII decimal 44) separator
character.

No additional content value encoding (i.e., BACKSLASH character
encoding) on an allowable
property, then the default is defined for this value type. START.

Example:

1234567890
-1234567890
+1234567890
432109876

4.3.9 Period of Time

Value

TRIGGER;RELATED=END:PT5M

4.2.14 Relationship Type

Parameter Name: PERIOD RELTYPE

Purpose: This value To specify the type is used to identify values that contain a
precise period of time.

Formal hierarchical relationship associated
with the calendar component specified by the property.

Format Definition: The data type property parameter is defined by the following
notation:

period = period-value *("," [WSP] period-value)

period-value

reltypeparam = period-explicit "RELTYPE" "="
("PARENT" ; Parent relationship. Default.
/ period-start

period-explicit = date-time "/" date-time
;ISO 8601 complete representation basic format for "CHILD" ; Child relationship
/ "SIBLING ; Sibling relationship
/ iana-token ; Some other IANA registered
; iCalendar relationship type
/ x-name) ; A non-standard, experimental
; relationship type

Description: This parameter can be specified on a period of time
;consisting property that
references another related calendar. The parameter specifies the
hierarchical relationship type of a start and end. the calendar component referenced
by the property. The start MUST parameter value can be before PARENT, to indicate that
the end. referenced calendar component is a superior of calendar
component; CHILD to indicate that the referenced calendar component
is a subordinate of the calendar component; SIBLING to indicate that
the referenced calendar component is a peer of the calendar

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period-start = date-time "/" duration
;ISO 8601 complete representation basic format for a period of time
;consisting of a start and duration of time.

Description:

component. If this parameter is not specified on an allowable
property, the property permits, multiple "period" values MAY default relationship type is PARENT.

Example:

RELATED-TO;RELTYPE=SIBLING:<19960401-080045-4000F192713@host.com>

Description: This parameter can be specified using a COMMA character (ASCII decimal 44) separator
character. There are two forms of on properties with a period of time. A period of time
MAY be identified by it's start and it's end. This format is
expressed as
CAL-ADDRESS value type. The parameter identifies the [ISO 8601] complete representation, basic format participation
status for
"DATE-TIME" start of the period, followed by a SOLIDUS character
(ASCII decimal 47), followed calendar user specified by the "DATE-TIME" property value. The
parameter values differ depending on whether they are associated with
a group scheduled "VEVENT", "VTODO" or "VJOURNAL". The values MUST
match one of the end of the
period. A period of time MAY also be defined by a start and a
duration of time. The format is expressed as the [ISO 8601] complete
representation, basic format values allowed for the "DATE-TIME" start of the period,
followed by given calendar component. If
not specified on a SOLIDUS character (ASCII decimal 47), followed by the
[ISO 8601] basic format for "DURATION" of property that allows this parameter, the period.

Example: The period starting at 18:00:00 UTC, on January 1, 1997 and
ending at 07:00:00 UTC on January 2, 1997 would be:

19970101T180000Z/19970102T070000Z

The period start at 18:00:00 on January 1, 1997 and lasting 5 hours
and 30 minutes would be:

19970101T180000Z/PT5H30M

No additional content default
value encoding (i.e., BACKSLASH character
encoding) is defined for this value type.

4.3.10 Recurrence Rule

Value NEEDS-ACTION.

Example:

ATTENDEE;PARTSTAT=DECLINED:MAILTO:jsmith@host.com

4.2.15 Participation Role

Parameter Name: RECURR ROLE

Purpose: This value type is used to identify properties that contain
a recurrence rule specification.

Formal Definition: The value type is defined by To specify the following
notation:

recur = recur-value *("," [WSP] recur-value)

recur-value = "FREQ"=freq ";"
[("UNTIL" "=" enddate ";") / ("COUNT" "=" 1*DIGIT ";")]
["INTERVAL" "=" 1*DIGIT ";"]
["BYSECOND" "=" byseclist ";"]
["BYMINUTE" "=" byminlist ";"]
["BYHOUR" "=" byhrlist ";"]
["BYDAY" "=" bywdaylist ";"]
["BYMONTHDAY" "=" bymodaylist ";"]
["BYYEARDAY" "=" byyrdaylist ";"]
["BYWEEKNO" "=" bywknolist ";"]
["BYMONTH" "=" bymolist ";"]
["BYSETPOS" "=" bysplist ";"]

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["WKST" "=" weekday ";")]
*(x-name "=" text) ";"
;Individual components MAY only be specified once.
;Rule components need not be participation role for the calendar user
specified in particular any order.

freq = "SECONDLY" / "MINUTELY" / "HOURLY" / "DAILY"
/ "WEEKLY" / "MONTHLY" / "YEARLY"

enddate = date
enddate =/ date-time ;A UTC value

byseclist = seconds / ( seconds *("," seconds) )

seconds = 1DIGIT / 2DIGIT ;0 to 59

byminlist = minutes / ( minutes *("," minutes) )

minutes = 1DIGIT / 2DIGIT ;0 to 59

byhrlist = hour / ( hour *("," hour) )

hour = 1DIGIT / 2DIGIT ;0 to 23

bywdaylist = weekdaynum / ( weekdaynum *("," weekdaynum) )

weekdaynum = [([plus] ordwk / minus ordwk)] weekday

plus = "+"

minus = "-"

ordwk = 1DIGIT / 2DIGIT ;1 to 53

weekday = "SU" / "MO" / "TU" / "WE" / "TH" / "FR" / "SA"
;Corresponding to SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY,
;FRIDAY, SATURDAY and SUNDAY days of by the week.

bymodaylist = monthdaynum / ( monthdaynum *("," monthdaynum) )

monthdaynum = ([plus] ordmoday) / (minus ordmoday)

ordmoday = 1DIGIT / 2DIGIT ;1 to 31

byyrdaylist = yeardaynum / ( yeardaynum *("," yeardaynum) )

yeardaynum = ([plus] ordyrday) / (minus ordyrday)

ordyrday property.

Format Definition: The property parameter is defined by the following
notation:

roleparam = 1DIGIT "ROLE" "="
("CHAIR" ; Indicates chair of the
; calendar entity
/ 2DIGIT "REQ-PARTICIPANT" ; Indicates a participant whose
; participation is required
/ 3DIGIT ;1 to 366

bywknolist = weeknum "OPT-PARTICIPANT" ; Indicates a participant whose
; participation is optional
/ ( weeknum *("," weeknum) )

weeknum = ([plus] ordwk) "NON-PARTICIPANT" ; Indicates a participant who is
; copied for information
; purposes only
/ (minus ordwk)

bymolist = monthnum x-name ; Experimental role
/ ( monthnum *("," monthnum) ) iana-token) ; Other IANA role
; Default is REQ-PARTICIPANT

Description: This parameter can be specified on properties with a
CAL-ADDRESS value type. The parameter specifies the participation
role for the calendar user specified by the property in the group
schedule calendar component. If not specified on a property that
allows this parameter, the default value is REQ-PARTICIPANT.

Example:

ATTENDEE;ROLE=CHAIR:MAILTO:mrbig@host.com

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monthnum = 1DIGIT / 2DIGIT ;1 to 12

bysplist = setposday / ( setposday *("," setposday) )

setposday = yeardaynum

Description: If the property permits, multiple "recur" values MAY be
specified using a COMMA character (ASCII decimal 44) separator
character. The value type

4.2.16 RSVP Expectation

Parameter Name: RSVP

Purpose: To specify whether there is a structured value consisting an expectation of a list favor of one or more recurrence grammar components. Each component is
defined by a NAME=VALUE pair. The components are separated
reply from each
other the calendar user specified by the SEMICOLON character (ASCII decimal 59). property value.

Format Definition: The components
are not ordered in any particular sequence. Individual components MAY
only property parameter is defined by the following
notation:

rsvpparam = "RSVP" "=" ("TRUE" / "FALSE")
; Default is FALSE

Description: This parameter can be specified once. on properties with a
CAL-ADDRESS value type. The FREQ component parameter identifies the type expectation of recurrence rule. This
component MUST be a
reply from the calendar user specified in by the recurrence rule. Valid values
include SECONDLY, property value. This
parameter is used by the "Organizer" to specify repeating events based on request a participation
status reply from an interval "Attendee" of a second group scheduled event or more; MINUTELY, to specify repeating events based to-do.
If not specified on an
interval of a minute or more; HOURLY, to property that allows this parameter, the
default value is FALSE.

Example:

ATTENDEE;RSVP=TRUE:MAILTO:jsmith@host.com

4.2.17 Sent By

Parameter Name: SENT-BY

Purpose: To specify repeating events
based the calendar user that is acting on an interval behalf of an hour or more; DAILY, to specify repeating
events based the
calendar user specified by the property.

Format Definition: The property parameter is defined by the following
notation:

sentbyparam = "SENT-BY" "=" DQUOTE cal-address DQUOTE

Description: This parameter can be specified on an interval of properties with a day or more; WEEKLY, to specify
repeating events based
CAL-ADDRESS value type. The parameter specifies the calendar user
that is acting on an interval behalf of the calendar user specified by the
property. The parameter value MUST be a week or more; MONTHLY, to MAILTO URI as defined in [RFC
1738]. The individual URI parameter values MUST be specified in a
quoted-string.

Example:

ORGANIZER;SENT-BY:"MAILTO:sray@host.com":MAILTO:jsmith@host.com

4.2.18 Time Zone Identifier

Parameter Name: TZID

Purpose: To specify the identifier for the time zone definition for a
time component in the property value.

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Format Definition: This property parameter is defined by the
following notation:

tzidparam = "TZID" "=" [tzidprefix] paramtext CRLF

tzidprefix = "/"

Description: The parameter MUST be specify repeating events based on an interval of a month or more; the "DTSTART", "DTEND",
"DUE", "EXDATE" and
YEARLY, to specify repeating events based on an interval of "RDATE" properties when either a year DATE-TIME or
more.

The INTERVAL component contains a positive integer representing how
often
TIME value type is specified and when the recurrence rule repeats. The default value is "1" or every
minute for a MINUTELY rule, every hour for a HOURLY rule, every day
for a DAILY rule, every week for a WEEKLY rule, every month for not either a
MONTHLY rule and every year for UTC
or a YEARLY rule.

The UNTIL component defines "floating" time. This property parameter specifies a date-time text value
which bounds uniquely identifies the
recurrence rule in an inclusive manner. If "VTIMEZONE" calendar component to be
used when evaluating the time portion of the property. The value specified by
UNTIL is synchronized with of
the specified recurrence, this date-time
becomes TZID property parameter will be equal to the last instance value of the recurrence. If not present, and TZID
property for the
COUNT matching time zone definition. An individual
"VTIMEZONE" calendar component is also not present, MUST be specified for each unique
"TZID" parameter value specified in the RRULE is considered to
repeat forever. iCalendar object.

The COUNT component defines the number of occurrences at which to
range-bound the recurrence. This component is ignored parameter MUST be specified on properties with a DATE-TIME value
if the "UNTIL"
component DATE-TIME is also present.

The BYSECOND component specifies not either a COMMA character (ASCII decimal 44)
separated list of seconds within UTC or a minute. Valid values are 0 to 59. "floating" time.

The BYMINUTE component specifies a COMMA presence of the SOLIDUS character (ASCII (US-ASCII decimal 44)
separated list 47) as a
prefix, indicates that this TZID represents a unique ID in a globally
defined time zone registry (when such registry is defined).

The following are examples of minutes within an hour. Valid this property parameter:

DTSTART;TZID=America-New_York:19980119T020000

DTEND;TZID=America-New_York:19980119T030000

The TZID property parameter MUST NOT be applied to DATE-TIME or TIME
properties whose time values are 0 to 59. specified in UTC.

The BYHOUR component specifies use of local time in a COMMA character (ASCII decimal 44)
separated list DATE-TIME or TIME value without the TZID
property parameter is to be interpreted as a local time value,
regardless of hours the existence of "VTIMEZONE" calendar components in the day. Valid values are 0 to 23.
iCalendar object.

For more information see the sections on the data types DATE-TIME and
TIME.

4.2.19 Value Data Types

Parameter Name: VALUE

Purpose: To explicitly specify the data type format for a property
value.

Format Definition: The BYDAY component "VALUE" property parameter is defined by the
following notation:

valuetypeparam = "VALUE" "=" valuetype

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valuetype = ("BINARY"
/ "BOOLEAN"
/ "CAL-ADDRESS"
/ "DATE"
/ "DATE-TIME"
/ "DURATION"
/ "FLOAT"
/ "INTEGER"
/ "PERIOD"
/ "RECUR"
/ "TEXT"
/ "TIME"
/ "URI"
/ "UTC-OFFSET"
/ x-name
; Some experimental iCalendar data type.
/ iana-token)
; Some other IANA registered iCalendar data type.

Description: The parameter specifies a COMMA character (ASCII decimal 44)
separated list of days the data type and format of the week; MO, indicates Monday; TU,

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indicates Tuesday; WE, indicates Wednesday; TH, indicates Thursday;
FR, indicates Friday; SA, indicates Saturday; SU, indicates Sunday.

Each BYDAY value MAY also
property value. The property values MUST be preceded by a positive (+n) or negative
(-n) integer. If present, this indicates the nth occurrence of the
specific day within the MONTHLY or YEARLY RRULE. a single value type.
For example, within a MONTHLY rule, +1MO (or simply 1MO) represents the first Monday
within the month, whereas -1MO represents the last Monday "RDATE" property cannot have a combination of the
month. DATE-
TIME and TIME value types.

If an integer modifier the property's value is not present, it means all days of
this type within the specified frequency. For example, within a
MONTHLY rule, MO represents all Mondays within default value type, then this
parameter need not be specified. However, if the month. property's default
value type is overridden by some other allowable value type, then
this parameter MUST be specified.

4.3 Property Value Data Types

The BYMONTHDAY component specifies a COMMA character (ASCII decimal
44) separated list of days properties in an iCalendar object are strongly typed. The
definition of each property restricts the month. Valid values are 1 value to 31 be one of the
value data types, or
-31 to -1.

Each BYMONTHDAY simply value MAY include types, defined in this section. The
value type for a positive (+n) property will either be specified implicitly as the
default value type or negative (-n)
integer. will be explicitly specified with the "VALUE"
parameter. If present, this indicates the nth occurrence value type of the
specific day a property is one of the month within alternate
valid types, then it MUST be explicitly specified with the MONTHLY rule. If an integer
modifier "VALUE"
parameter.

4.3.1 Binary

Value Name: BINARY

Purpose: This value type is not present, it means all days used to identify properties that contain
a character encoding of this type within the
specified frequency. inline binary data. For example, within a MONTHLY rule, -10
represents an inline
attachment of an object code might be included in an iCalendar
object.

Formal Definition: The value type is defined by the tenth to following
notation:

binary = *(4b-char) [b-end]
; A "BASE64" encoded character string, as defined by [RFC 2045].

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b-end = (2b-char "==") / (3b-char "=")

b-char = ALPHA / DIGIT / "+" / "/"

Description: Property values with this value type MUST also include
the last day inline encoding parameter sequence of ";ENCODING=BASE64". That
is, all inline binary data MUST first be character encoded using the month.

The BYYEARDAY component specifies a COMMA
"BASE64" encoding method defined in [RFC 2045]. No additional content
value encoding (i.e., BACKSLASH character (ASCII decimal
44) separated list encoding) is defined for
this value type.

Example: The following is an abridged example of days a "BASE64" encoded
binary value data.

ATTACH;VALUE=BINARY;ENCODING=BASE64:MIICajCCAdOgAwIBAgICBEUwDQY
JKoZIhvcNAQEEBQAwdzELMAkGA1UEBhMCVVMxLDAqBgNVBAoTI05ldHNjYXBlI
ENvbW11bmljYXRpb25zIENvcnBvcmF0aW9uMRwwGgYDVQQLExNJbmZv
<...remainder of the year. Valid values are 1 "BASE64" encoded binary data...>

4.3.2 Boolean

Value Name: BOOLEAN

Purpose: This value type is used to 366 identify properties that contain
either a "TRUE" or
-366 to -1. For example, -1 represents the last day of the year
(December 31st). "FALSE" Boolean value.

Formal Definition: The BYWEEKNO component specifies a comma-separated list of weeks of value type is defind by the year. Valid following
notation:

boolean = "TRUE" / "FALSE"

Description: These values are 1 to 53. case insensitive text. No additional
content value encoding (i.e., BACKSLASH character encoding) is
defined for this value type.

Example: The following is an example of a hypothetical property that
has a BOOLEAN value type:

GIBBERISH:TRUE

4.3.3 Calendar User Address

Value Name: CAL-ADDRESS

Purpose: This corresponds to weeks
according value type is used to week numbering identify properties that contain
a calendar user address.

Formal Definition: The value type is as defined in [ISO 8601]. That is, by the following
notation:

cal-address = uri

Description: The value is a week URI as "A seven day period within defined by [RFC 1738] or any other
IANA registered form for a calendar year, starting on URI. When used to address an Internet

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email transport address for a Monday
and identified by its ordinal number within the year; the first calendar week of the year is the one that includes user, the first Thursday
of that year." This component is only valid for YEARLY rules.

Each BYWEEKNO value MAY include MUST be a positive (+n) or negative (-n)
integer. If present, this indicates the nth occurrence of the
specific week of the year within the YEARLY rule. If an integer
modifier
MAILTO URI, as defined by [RFC 1738]. No additional content value
encoding (i.e., BACKSLASH character encoding) is not present, it means all days of defined for this
value type.

Example:

ATTENDEE:MAILTO:jane_doe@host.com

4.3.4 Date

Value Name: DATE

Purpose: This value type within is used to identify values that contain a
calendar date.

Formal Definition: The value type is defined by the following
notation:

date = date-value

date-value = date-fullyear date-month date-mday
date-fullyear = 4DIGIT
date-month = 2DIGIT ;01-12
date-mday = 2DIGIT ;01-28, 01-29, 01-30, 01-31
;based on month/year

Description: If the property permits, multiple "date" values can be
specified frequency. For example, within using a YEARLY rule, 3 represents COMMA character (US-ASCII decimal 44) separator
character. The format for the third week of value type is expressed as the year. [ISO
8601] complete representation, basic format for a calendar date. The BYMONTH component
textual format specifies a comma separated list of months four-digit year, two-digit month, and two-
digit day of the year. Valid values month. There are 1 to 12.

The WKST component specifies the day on which no separator characters between the workweek starts.
Valid values are MO, TU, WE, TH, FR, SA and SU. This is significant
when a WEEKLY RRULE has an interval greater than 1,
year, month and a BYDAY day component text.

No additional content value encoding (i.e., BACKSLASH character
encoding) is specified. defined for this value type.

Example: The default following represents July 14, 1997:

19970714

4.3.5 Date-Time

Value Name: DATE-TIME

Purpose: This value type is MO.

The BYSETPOS component specifies used to identify values that specify a COMMA character (ASCII decimal 44)
separated list
precise calendar date and time of values which corresponds to the nth occurrence
within day.

Formal Definition: The value type is defined by the set of events following
notation:

date-time = date "T" time ;As specified by in the rule. Valid values are 1 to date and time
;value definitions

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366 or -366 to -1. It MUST only be used in conjunction with another
Byxxx component. For example "the last work day of

Description: If the month" could
be represented as:

RRULE:FREQ=MONTHLY;BYDAY=MO,TU,WE,TH,FR;BYSETPOS=-1

Each BYSETPOS value property permits, multiple "date-time" values MAY include
be specified using a positive (+n) or negative (-n)
integer. If present, COMMA character (US-ASCII decimal 44) separator
character. No additional content value encoding (i.e., BACKSLASH
character encoding) is defined for this indicates value type.

The "DATE-TIME" data type is used to identify values that contain a
precise calendar date and time of day. The format is based on the nth occurrence
[ISO 8601] complete representation, basic format for a calendar date
and time of day. The text format is a concatenation of the
specific occurrence within "date",
followed by the set of events specified LATIN CAPITAL LETTER T character (US-ASCII decimal
84) time designator, followed by the rule.

If BYxxx component "time" format.

The "DATE-TIME" data type expresses time values in three forms:

The form of date and time with UTC offset MUST NOT be used. For
example, the following is not valid for a date-time value:

DTSTART:19980119T230000-0800 ;Invalid time format

FORM #1: DATE WITH LOCAL TIME

The date with local time form is simply a date-time value that does
not contain the UTC designator nor does it reference a time zone. For
example, the following represents Janurary 18, 1998, at 11 PM:

DTSTART:19980118T230000

Date-time values of this type are found which are beyond the available
scope (ie, BYMONTHDAY=30 in February), they said to be "floating" and are simply ignored.

Information, not contained in the rule, necessary
bound to determine the
various recurrence instance start any time and dates zone in particular. They are derived from used to represent the
Start Time (DTSTART) entry attribute.
same hour, minute, and second value regardless of which time zone is
currently being observed. For example,
"FREQ=YEARLY;BYMONTH=1" doesn't specify a specific day within an event can be defined that
indicates that an individual will be busy from 11:00 AM to 1:00 PM
every day, no matter which time zone the
month or person is in. In these
cases, a time. This information would local time can be specified. The recipient of an iCalendar
object with a property value consisting of a local time, without any
relative time zone information, should interpret the same value as what is
specified for DTSTART.

BYxxx components modify being
fixed to whatever time zone the recurrence ATTENDEE is in some manner. BYxxx
components for a period of at any given moment.
This means that two ATTENDEEs, in different time which is zones, receiving the
same or greater than event definition as a floating time, may be participating in the
frequency generally reduce or limit
event at different actual times. Floating time should only be used
where that is the number reasonable behavior.

In most cases, a fixed time is desired. To properly communicate a
fixed time in a property value, either UTC time or local time with
time zone reference MUST be specified.

The use of occurrences local time in a DATE-TIME value without the TZID property
parameter is to be interpreted as floating time, regardless of the
recurrence generated. For example, "FREQ=DAILY;BYMONTH=1" reduces the
number
existence of recurrence instances from all days (if BYMONTH tag is not
present) to all days in January. BYxxx "VTIMEZONE" calendar components for a period of
time less than in the frequency generally increase iCalendar object.

FORM #2: DATE WITH UTC TIME

The date with UTC time, or expand absolute time, is identified by a LATIN
CAPITAL LETTER Z suffix character (US-ASCII decimal 90), the number
of occurrences of UTC

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designator, appended to the recurrence. time value. For example,
"FREQ=YEARLY;BYMONTH=1,2" increases the number of days within the
yearly recurrence set from 1 (if BYMONTH tag is not present) following
represents January 19, 1998, at 0700 UTC:

DTSTART:19980119T070000Z

The TZID property parameter MUST NOT be applied to 2.

If only one BYxxx component is DATE-TIME
properties whose time values are specified in UTC.

FORM #3: DATE WITH LOCAL TIME AND TIME ZONE REFERENCE

The date and local time with reference to time zone information is
identified by the recurrence rule, use the
list of "n" unique values would cause "n" occurrences of TZID property parameter to reference the
recurrence within each specified frequency interval, where each
unique list value
appropriate time zone definition. TZID is substituted discussed in detail in the appropriate date position
within DTSTART for
section on Time Zone. For example, the following represents 2 AM in
New York on Janurary 19, 1998:

DTSTART;TZID=America-New_York:19980119T020000

Example: The following represents July 14, 1997, at 1:30 PM in New
York City in each such occurrence.

If multiple BYxxx components are specified, then after evaluating of the three time formats, using the
specified FREQ "DTSTART"
property.

DTSTART:19970714T133000 ;Local time
DTSTART:19970714T173000Z ;UTC time
DTSTART;TZID=America-NYC:19970714T133000 ;Local time and INTERVAL components, the BYxxx components are
applied to time
; zone reference

A time value MUST ONLY specify 60 seconds when specifying the current set of evaluated occurrences
periodic "leap second" in the following
order: BYMONTH, BYWEEKNO, BYYEARDAY, BYMONTHDAY, BYDAY, BYHOUR,
BYMINUTE, BYSECOND and BYSETPOS.

Here time value. For example:

COMPLETED:19970630T235960Z

4.3.6 Duration

Value Name: DURATION

Purpose: This value type is an example used to identify properties that contain
a duration of evaluating multiple BYxxx components.

DTSTART;TZID=EST=19970105T083000
RRULE:FREQ=YEARLY;INTERVAL=2;BYMONTH=1;BYDAY=SU;BYHOUR=8,9;
BYMINUTE=30

First, time.

Formal Definition: The value type is defined by the "INTERVAL=2" would be applied to "FREQ=YEARLY" to arrive
at "every other year". Then, "BYMONTH=1" would be applied to arrive
at "every January, every other year". Then, "BYDAY=SU" would be
applied to arrive at "every Sunday in January, every other year".
Then, "BYHOUR=8,9" would following
notation:

duration = (["+"] / "-") "P" (dur-date / dur-time / dur-week)

dur-date = dur-day [dur-time]
dur-time = "T" (dur-hour / dur-minute / dur-second)
dur-week = 1*DIGIT "W"
dur-hour = 1*DIGIT "H" [dur-minute]
dur-minute = 1*DIGIT "M" [dur-second]
dur-second = 1*DIGIT "S"
dur-day = 1*DIGIT "D"

Description: If the property permits, multiple "duration" values can
be applied to arrive at "every Sunday in specified using a COMMA character (US-ASCII decimal 44) separator

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January at 8 AM and 9 AM, every other year". Then, "BYMINUTE=30"
would be applied to arrive at "every Sunday in January at 8:30 AM and
9:30 AM, every other year". Similarly, if the BYMINUTE, BYHOUR,
BYDAY, BYMONTHDAY or BYMONTH component were missing,

character. The format is expressed as the appropriate
minute, hour, day or month would have been retrieved from [ISO 8601] basic format for
the
"DTSTART" property. duration of time. The format can represent durations in terms of
weeks, days, hours, minutes, and seconds.

No additional content value encoding (i.e., BACKSLASH character
encoding) is are defined for this value type.

Example: The following is a rule which specifies 10 meetings which
occur every other day:

FREQ=DAILY;COUNT=10;INTERVAL=2

There are other examples specified in the "RRULE" specification.

4.3.11 Text A duration of 15 days, 5 hours and 20 seconds would be:

P15DT5H0M20S

A duration of 7 weeks would be:

P7W

4.3.7 Float

Value Name: TEXT

Purpose FLOAT

Purpose: This value type is used to identify values properties that contain human
readable text.
a real value number value.

Formal Definition: The value type is defined by the following
notation:

text = text-value *("," text-value)
; Folded according to folded-value syntax above or
; encoded according to param-value syntax above.

text-value = *(SAFE-CHAR / ":" / DQUOTE / ESCAPED-CHAR)

ESCAPED-CHAR

float = "\\" / "\;" / "\," / "\N" (["+"] / "\n")
; \\ encodes \, \N or \n encodes newline
; \; encodes ;, \, encodes ,

NON-ASCII = %x80-FF
; use restricted "-") 1*DIGIT ["." 1*DIGIT]

Description: If the property permits, multiple "float" values can be
specified using a COMMA character (US-ASCII decimal 44) separator
character.

No additional content value encoding (i.e., BACKSLASH character
encoding) is defined for this value type.

Example:

1000000.0000001
1.333
-3.14

4.3.8 Integer

Value Name:INTEGER

Purpose: This value type is used to identify properties that contain
a signed integer value.

Formal Definition: The value type is defined by charset parameter
; on outer MIME object

SAFE-CHAR the following
notation:

integer = %x20-21 / %x23-2B / %x2D-39 / %x3C-5B
%x5D-7E (["+"] / NON-ASCII
; Any character except CTLs, DQUOTE, ";", ":", "\", "," "-") 1*DIGIT

Description: If the property permits, multiple "text" "integer" values MAY can
be specified using a COMMA character (ASCII (US-ASCII decimal 44) separator

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character. The character set and language in which valid range for "integer" is -2147483648 to
2147483647. If the text sign is
represented not specified, then the value is controlled by assumed
to be positive. If the "LANGUAGE" property parameters.

An intentional formatted text line break MAY only permits, multiple "integer" values
can be included in specified using a
"TEXT" property COMMA character (US-ASCII decimal 44)
separator character.

No additional content value by representing the line break with the encoding (i.e., BACKSLASH character sequence
encoding) is defined for this value type.

Example:

1234567890
-1234567890
+1234567890
432109876

4.3.9 Period of BACKSLASH (ASCII decimal 92), followed Time

Value Name: PERIOD

Purpose: This value type is used to identify values that contain a
precise period of time.

Formal Definition: The data type is defined by the following
notation:

period = period-explicit / period-start

period-explicit = date-time "/" date-time
; [ISO 8601] complete representation basic format for a

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LATIN SMALL LETTER N (ASCII decimal 110) or period of
; time consisting of a LATIN CAPITAL LETTER N
(ASCII decimal 78), that is "\n" or "\N". start and end. The "TEXT" start MUST be before the
; end.

period-start = date-time "/" duration
; [ISO 8601] complete representation basic format for a period of
; time consisting of a start and positive duration of time.

Description: If the property permits, multiple "period" values may also contain special characters that
are used to signify delimiters, such as can be
specified using a COMMA character for lists (US-ASCII decimal 44) separator
character. There are two forms of values or a SEMICOLON character for structured values. In order to
support period of time. A period of time
is identified by its start and its end. This format is expressed as
the inclusion [ISO 8601] complete representation, basic format for "DATE-TIME"
start of these special characters in "TEXT" property
values, they need to be escaped with the period, followed by a BACKSLASH character. A
BACKSLASH SOLIDUS character (ASCII (US-ASCII
decimal 92) in a "TEXT" property value 47), followed by the "DATE-TIME" of the end of the period.
The start of the period MUST be escaped with another BACKSLASH character. before the end of the period. A COMMA character
in a "TEXT" property value MUST
period of time can also be escaped with defined by a BACKSLASH character
(ASCII decimal 92). A SEMICOLON character in start and a "TEXT" property value
MUST be escaped with positive duration
of time. The format is expressed as the [ISO 8601] complete
representation, basic format for the "DATE-TIME" start of the period,
followed by a BACKSLASH SOLIDUS character (ASCII (US-ASCII decimal 92).
However, a COLON character in a "TEXT" property value SHALL NOT be
escaped with a 47), followed by
the [ISO 8601] basic format for "DURATION" of the period.

Example: The period starting at 18:00:00 UTC, on January 1, 1997 and
ending at 07:00:00 UTC on January 2, 1997 would be:

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19970101T180000Z/19970102T070000Z

The period start at 18:00:00 on January 1, 1997 and lasting 5 hours
and 30 minutes would be:

19970101T180000Z/PT5H30M

No additional content value encoding (i.e., BACKSLASH character.Example: A multiple line character
encoding) is defined for this value of:

Project XYZ Final Review
Conference Room - 3B
Come Prepared.

would be represented as:

Project XYZ Final Review\n Conference Room - 3B\nCome Prepared.

4.3.12 Time type.

4.3.10 Recurrence Rule

Value Name: TIME RECUR

Purpose: This value type is used to identify values properties that contain
a
time of day. recurrence rule specification.

Formal Definition: The data value type is defined by the following
notation:

time

recur = "FREQ"=freq
[(";" "UNTIL" "=" enddate) / (";" "COUNT" "=" 1*DIGIT)]
[";" "INTERVAL" "=" 1*DIGIT]
[";" "BYSECOND" "=" byseclist]
[";" "BYMINUTE" "=" byminlist]
[";" "BYHOUR" "=" byhrlist]
[";" "BYDAY" "=" bywdaylist]
[";" "BYMONTHDAY" "=" bymodaylist]
[";" "BYYEARDAY" "=" byyrdaylist]
[";" "BYWEEKNO" "=" bywknolist]
[";" "BYMONTH" "=" bymolist]
[";" "BYSETPOS" "=" bysplist]
[";" "WKST" "=" weekday)]
*(";" x-name "=" text)
;Individual rule parts MUST only be specified once.
;Rule parts need not be specified in particular any order.

freq = "SECONDLY" / "MINUTELY" / "HOURLY" / "DAILY"
/ "WEEKLY" / "MONTHLY" / "YEARLY"

enddate = date
enddate =/ date-time ;An UTC value

byseclist = seconds / ( seconds *("," seconds) )

seconds = 1DIGIT / 2DIGIT ;0 to 59

byminlist = minutes / ( minutes *("," minutes) )

minutes = 1DIGIT / 2DIGIT ;0 to 59

byhrlist = hour / ( hour *("," hour) )

hour = 1DIGIT / 2DIGIT ;0 to 23

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bywdaylist = weekdaynum / ( weekdaynum *("," weekdaynum) )

weekdaynum = [([plus] ordwk / minus ordwk)] weekday

plus = "+"

minus = "-"

ordwk = 1DIGIT / 2DIGIT ;1 to 53

weekday = "SU" / "MO" / "TU" / "WE" / "TH" / "FR" / "SA"
;Corresponding to SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY,
;FRIDAY, SATURDAY and SUNDAY days of the week.

bymodaylist = time-value monthdaynum / ( monthdaynum *("," [WSP] time-value)

time-value monthdaynum) )

monthdaynum = time-hour time-minute time-second [time-utc]

time-hour ([plus] ordmoday) / (minus ordmoday)

ordmoday = 1DIGIT / 2DIGIT ;00-23
time-minute ;1 to 31

byyrdaylist = yeardaynum / ( yeardaynum *("," yeardaynum) )

yeardaynum = ([plus] ordyrday) / (minus ordyrday)

ordyrday = 1DIGIT / 2DIGIT ;00-59
time-second / 3DIGIT ;1 to 366

bywknolist = weeknum / ( weeknum *("," weeknum) )

weeknum = ([plus] ordwk) / (minus ordwk)

bymolist = monthnum / ( monthnum *("," monthnum) )

monthnum = 1DIGIT / 2DIGIT ;00-60
;The "60" value is used ;1 to account for years with "leap" seconds.

time-utc 12

bysplist = "Z" setposday / ( setposday *("," setposday) )

setposday = yeardaynum

Description: If the property permits, multiple "time" "recur" values MAY can be
specified using a COMMA character (ASCII (US-ASCII decimal 44) separator
character. No additional content The value encoding (i.e., BACKSLASH
character encoding) type is defined for this a structured value type. consisting of a list
of one or more recurrence grammar parts. Each rule part is defined by
a NAME=VALUE pair. The "TIME" data rule parts are separated from each other by
the SEMICOLON character (US-ASCII decimal 59). The rule parts are not
ordered in any particular sequence. Individual rule parts MUST only
be specified once.

The FREQ rule part identifies the type is used to identify of recurrence rule. This rule
part MUST be specified in the recurrence rule. Valid values that contain include
SECONDLY, to specify repeating events based on an interval of a time
second or more; MINUTELY, to specify repeating events based on an
interval of day. The format is a minute or more; HOURLY, to specify repeating events
based on an interval of an hour or more; DAILY, to specify repeating
events based on the [ISO 8601] complete an interval of a day or more; WEEKLY, to specify

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representation, basic format for a time of day. The text format
consists

repeating events based on an interval of a two-digit 24-hour week or more; MONTHLY, to
specify repeating events based on an interval of the day (i.e., values 0-23), two-
digit minute in the hour (i.e., values 0-59), a month or more; and two-digit seconds
in the minute (i.e., values 0-59). Fractions
YEARLY, to specify repeating events based on an interval of a second are not
supported by this format.

In parallel to the "DATE-TIME" definition above, the "TIME" data type
expresses time values in three forms:

Note: year or
more.

The form of time with UTC offset MUST NOT be used. For example, INTERVAL rule part contains a positive integer representing how
often the following recurrence rule repeats. The default value is NOT VALID "1" or every
second for a time value:

230000-0800

FORM #1 LOCAL TIME

The local time form is simply SECONDLY rule, or every minute for a time value that does not contain the
UTC designator nor does it reference MINUTELY rule,
every hour for an HOURLY rule, every day for a time zone. For example, 11 PM:

230000

Time values of this type are said to be "floating" and are not bound
to any time zone in particular. They are used to represent the same
hour, minute, DAILY rule, every week
for a WEEKLY rule, every month for a MONTHLY rule and second every year for
a YEARLY rule.

The UNTIL rule part defines a date-time value regardless of which time zone is
currently being observed. For example, an event MAY be defined that
indicates that bounds the
recurrence rule in an individual will be busy from 11:00 AM to 1:00 PM
every day, no matter which timezone inclusive manner. If the person value specified by
UNTIL is in. In these cases,
a local time MAY be specified. The recipient of an iCalendar object synchronized with a property value consisting the specified recurrence, this date or
date-time becomes the last instance of a local time, without any
relative time zone information, should interpret the value recurrence. If specified
as being
fixed to whatever timezone the ATTENDEE is in at any given moment.
This means that two ATTENDEEs may participate a date-time value, then it MUST be specified in the same event at
different an UTC times; floating time should only be used where that
format. If not present, and the COUNT rule part is
reasonable behavior.

In most cases, a fixed time also not present,
the RRULE is desired. To properly communicate a
fixed time in a considered to repeat forever.

The COUNT rule part defines the number of occurrences at which to
range-bound the recurrence. The "DTSTART" property value, either UTC time or local time with
time zone reference MUST be specified. if
specified, counts as the first occurrence.

The use BYSECOND rule part specifies a COMMA character (US-ASCII decimal
44) separated list of local time in seconds within a minute. Valid values are 0 to
59. The BYMINUTE rule part specifies a COMMA character (US-ASCII
decimal 44) separated list of minutes within an hour. Valid values
are 0 to 59. The BYHOUR rule part specifies a TIME value without COMMA character (US-
ASCII decimal 44) separated list of hours of the TZID property
parameter is day. Valid values
are 0 to be interpreted as 23.

The BYDAY rule part specifies a local time value, regardless COMMA character (US-ASCII decimal 44)
separated list of days of the existence week; MO, indicates Monday; TU,
indicates Tuesday; WE, indicates Wednesday; TH, indicates Thursday;
FR, indicates Friday; SA, indicates Saturday; SU, indicates Sunday.

Each BYDAY value can also be preceded by a positive (+n) or negative
(-n) integer. If present, this indicates the nth occurrence of "VTIMEZONE" calendar components in the iCalendar
object.

FORM #2: DATE WITH UTC TIME

UTC time,
specific day within the MONTHLY or absolute time, YEARLY RRULE. For example, within
a MONTHLY rule, +1MO (or simply 1MO) represents the first Monday
within the month, whereas -1MO represents the last Monday of the
month. If an integer modifier is identified by not present, it means all days of
this type within the specified frequency. For example, within a LATIN CAPITAL LETTER Z
suffix
MONTHLY rule, MO represents all Mondays within the month.

The BYMONTHDAY rule part specifies a COMMA character (ASCII decimal 90),
44) separated list of days of the UTC designator, appended month. Valid values are 1 to
the time value. 31 or
-31 to -1. For example, the following -10 represents 0700 UTC:

070000Z

The TZID property parameter MUST NOT be applied the tenth to TIME properties
whose time the last day of
the month.

The BYYEARDAY rule part specifies a COMMA character (US-ASCII
decimal 44) separated list of days of the year. Valid values are specified in UTC. 1 to
366 or -366 to -1. For example, -1 represents the last day of the

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FORM #3: DATE WITH LOCAL TIME AND TIME ZONE REFERENCE

The local time with reference to time zone information form is
identified by the use

year (December 31st) and -306 represents the TZID property parameter 306th to reference the
appropriate time zone definition. TZID is discussed in detail in last day of
the
section on Time Zone.

Example: year (March 1st).

The following represents 8:30 AM in New York, five hours
behind UTC, in each BYWEEKNO rule part specifies a COMMA character (US-ASCII decimal
44) separated list of ordinals specifying weeks of the three formats using the "DTSTART"
property:

DTSTART:19980312T083000

DTSTART:19980312T133000Z

DTSTART;TZID=America-New York:19980312T083000

4.3.13 URI

Value Name: URI

Purpose: year. Valid
values are 1 to 53 or -53 to -1. This value type is used corresponds to identify values weeks according
to week numbering as defined in [ISO 8601]. The first calendar week
of the year is the one that contain a
uniform resource identifier (URI) type includes the first 4 days of reference to the property
value.

Formal Definition: The data type year. A
week is defined by as a seven day period, starting on the following
notation:

uri = <As day of the
week defined by any IETF RFC>

Description: This data type might be used to reference binary
information, be the week start (see WKST). This rule part is only
valid for YEARLY rules. For example, 3 represents the third week of
the year.

Note: Assuming a Monday week start, week 53 can only occur when
Thursday is January 1 or if it is a leap year and Wednesday is
January 1.

The BYMONTH rule part specifies a COMMA character (US-ASCII decimal
44) separated list of months of the year. Valid values that are large, or otherwise undesirable 1 to
include directly in the iCalendar object. 12.

The URI value formats in RFC 1738, RFC 2111 and any other IETF
registered value format MAY be specified.

Any IANA registered URI format MAY be used. These include, but WKST rule part specifies the day on which the workweek starts.
Valid values are
not limited to, those defined in RFC 1738 MO, TU WE , , TH, FR, SA and RFC 2111.

When a property parameter value SU. This is significant
when a URI value type, the URI must be
specified as WEEKLY RRULE has an interval greater than 1, and a quoted-string value.

No additional content value encoding (i.e., BACKSLASH character
encoding) BYDAY rule
part is defined for this value type.

Example: The following specified. This is also significant when in a URI for YEARLY RRULE
when a network file:

http://host1.com/my-report.txt

4.3.14 UTC Offset

Value Name: UTC-OFFSET

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Purpose: This value type BYWEEKNO rule part is used to identify properties that contain
an offset from UTC to local time.

Formal Definition: specified. The data type default value is defined by the following
notation:

utc-offset = time-numzone ;As defined above in time data
type

Description: MO.

The PLUS SIGN BYSETPOS rule part specifies a COMMA character (US-ASCII decimal
44) separated list of values which corresponds to the nth occurrence
within the set of events specified by the rule. Valid values are 1 to
366 or -366 to -1. It MUST only be used in conjunction with another
Byxxx rule part. For example "the last work day of the month" could
be specified for positive UTC offsets.

No additional content represented as:

RRULE:FREQ=MONTHLY;BYDAY=MO,TU,WE,TH,FR;BYSETPOS=-1

Each BYSETPOS value encoding (i.e., BACKSLASH character
encoding) is defined for can include a positive (+n) or negative (-n)
integer. If present, this value type.

Example: The following indicates the nth occurrence of the
specific occurrence within the set of events specified by the rule.

If BYxxx rule part values are UTC offsets found which are given for standard beyond the available
scope (ie, BYMONTHDAY=30 in February), they are simply ignored.

Information, not contained in the rule, necessary to determine the
various recurrence instance start time
for New York (five hours behind UTC) and Geneva (one hour ahead of
UTC):

-0500

+0100

4.4 iCalendar Object

The Calendaring and Scheduling Core Object is dates are derived from the
Start Time (DTSTART) entry attribute. For example,
"FREQ=YEARLY;BYMONTH=1" doesn't specify a collection of
calendaring and scheduling information. Typically, this information
will consist of specific day within the
month or a single iCalendar object. However, multiple
iCalendar objects MAY time. This information would be sequentially grouped together. The first
line and last line of the iCalendar object MUST contain a pair of
iCalendar object delimiter strings. The syntax for an iCalendar
object is same as follows:

icalobject = "BEGIN" ":" [WSP] "VCALENDAR" CRLF
icalbody
"END" ":" [WSP] "VCALENDAR" CRLF [icalobject]

The following what is
specified for DTSTART.

BYxxx rule parts modify the recurrence in some manner. BYxxx rule
parts for a simple example period of time which is the same or greater than the
frequency generally reduce or limit the number of occurrences of an iCalendar object:

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//hacksw/handcal//NONSGML v1.0//EN
BEGIN:VEVENT
DTSTART:19970714T170000Z
DTEND:19970715T045959Z
SUMMARY:Bastille Day Party
END:VEVENT
END:VCALENDAR the
recurrence generated. For example, "FREQ=DAILY;BYMONTH=1" reduces the
number of recurrence instances from all days (if BYMONTH tag is not

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4.5 Property

A property

present) to all days in January. BYxxx rule parts for a period of
time less than the frequency generally increase or expand the number
of occurrences of the recurrence. For example,
"FREQ=YEARLY;BYMONTH=1,2" increases the number of days within the
yearly recurrence set from 1 (if BYMONTH tag is not present) to 2.

If multiple BYxxx rule parts are specified, then after evaluating the
specified FREQ and INTERVAL rule parts, the BYxxx rule parts are
applied to the current set of evaluated occurrences in the following
order: BYMONTH, BYWEEKNO, BYYEARDAY, BYMONTHDAY, BYDAY, BYHOUR,
BYMINUTE, BYSECOND and BYSETPOS; then COUNT and UNTIL are evaluated.

Here is an example of evaluating multiple BYxxx rule parts.

DTSTART;TZID=US-Eastern:19970105T083000
RRULE:FREQ=YEARLY;INTERVAL=2;BYMONTH=1;BYDAY=SU;BYHOUR=8,9;
BYMINUTE=30

First, the "INTERVAL=2" would be applied to "FREQ=YEARLY" to arrive
at "every other year". Then, "BYMONTH=1" would be applied to arrive
at "every January, every other year". Then, "BYDAY=SU" would be
applied to arrive at "every Sunday in January, every other year".
Then, "BYHOUR=8,9" would be applied to arrive at "every Sunday in
January at 8 AM and 9 AM, every other year". Then, "BYMINUTE=30"
would be applied to arrive at "every Sunday in January at 8:30 AM and
9:30 AM, every other year". Then, lacking information from RRULE, the
second is derived from DTSTART, to end up in "every day in January at
8:30:00 AM and 9:30:00 AM, every other year". Similarly, if the definition of an individual attribute describing a
calendar property
BYMINUTE, BYHOUR, BYDAY, BYMONTHDAY or a calendar component. A property takes BYMONTH rule part were
missing, the form
defined by appropriate minute, hour, day or month would have been
retrieved from the "contentline" notation "DTSTART" property.

No additional content value encoding (i.e., BACKSLASH character
encoding) is defined in section 4.1.1. for this value type.

Example: The following is an example of a property:

DTSTART:19960415T133000Z

This memo places no imposed ordering of properties within an
iCalendar object.

Property names, parameter names and parameter values (i.e.,
everything to the left of the ":" on a line) rule which specifies 10 meetings which
occur every other day:

FREQ=DAILY;COUNT=10;INTERVAL=2

There are case insensitive.
For example, other examples specified in the property name "DUE" "RRULE" specification.

4.3.11 Text

Value Name: TEXT

Purpose This value type is used to identify values that contain human
readable text.

Formal Definition: If the same as "due" and "Due".

4.6 Calendar Components

The body of character set is UTF-8, the iCalendar object consists of a sequence of calendar
properties and one or more calendar components. The calendar
properties are attributes that apply to value type is
defined by the calendar as a whole. The
calendar components are collections of properties that express a
particular calendar semantic. following notation. This must be modified depending on
character sets. For example, the calendar component MAY
specify an event, a to-do, a journal entry, time zone information, or
free/busy time information, or an alarm.

The body definition of TSAFE-CHAR includes
ESC for character sets that use ISO 2022 character set switching and

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TSAFE-CHAR should not include NON-US-ASCII when the iCalenar object character set is defined by the following notation:

icalbody = calprops 1*component

calprops
US-ASCII.

text = [calscale] [method] prodid version

component *(TSAFE-CHAR / ":" / DQUOTE / ESCAPED-CHAR)
; Folded according to description above

ESCAPED-CHAR = 1*(eventc "\\" / todoc "\;" / journalc "\," / freebusyc "\N" / "\n")
; \\ encodes \, \N or \n encodes newline
; \; encodes ;, \, encodes ,

TSAFE-CHAR = %x20-21 / %x23-2B / timezonec %x2D-39 / x-name %x3C-5B
%x5D-7E / iana-token) NON-US-ASCII
; Any character except CTLs not needed by the current
; character set, DQUOTE, ";", ":", "\", ","

Description: If the property permits, multiple "text" values can be
specified using a COMMA character (US-ASCII decimal 44) separator
character.

The language in which the text is represented can be controlled by
the "LANGUAGE" property parameter.

An iCalendar object must include intentional formatted text line break MUST only be included in a
"TEXT" property value by representing the "PRODID" and "VERSION" calendar
properties. In addition, it must include at least one calendar
component. Special forms line break with the
character sequence of iCalendar objects are possible to publish
just busy time (i.e., only BACKSLASH (US-ASCII decimal 92), followed by a "VFREEBUSY" calendar component)
LATIN SMALL LETTER N (US-ASCII decimal 110) or time
zone (i.e., only a "VTIMEZONE" calendar component) information. In
addition, a complex iCalendar object is possible LATIN CAPITAL LETTER
N (US-ASCII decimal 78), that is "\n" or "\N".

The "TEXT" property values may also contain special characters that
are used to
capture a complete snapshot of the contents of signify delimiters, such as a calendar (e.g.,
composite of many different calendar components). More commonly, an
iCalendar object will consist COMMA character for lists
of just a single "VEVENT", "VTODO" values or
"VJOURNAL" calendar component.

4.6.1 Event Component

Component Name: "VEVENT"

Purpose: Provide a grouping SEMICOLON character for structured values. In order to
support the inclusion of component properties that describe an
event.

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Format Definition: these special characters in "TEXT" property
values, they need to be escaped with a BACKSLASH character. A "VEVENT" calendar component is defined by the
following notation:

eventc = "BEGIN" ":" [WSP] "VEVENT" CRLF
eventprop *alarmc
"END" ":" [WSP] "VEVENT" CRLF

eventprop = *attach *attendee *categories [class] *comment
*contact [created] [description] [dtend / duration]
dtstart *exdate *exrule [geo] [last-mod] [location]
[organizer] [priority] [rstatus] *related *resources
*rdate *rrule dtstamp [seq] [status] summary
[transp] uid [url] [recurid]

Description:
BACKSLASH character (US-ASCII decimal 92) in a "TEXT" property value
MUST be escaped with another BACKSLASH character. A "VEVENT" calendar component is COMMA character
in a grouping of component
properties and an OPTIONAL "VALARM" calendar component that represent "TEXT" property value MUST be escaped with a scheduled amount of time on BACKSLASH character
(US-ASCII decimal 92). A SEMICOLON character in a calendar. For example, it MAY "TEXT" property
value MUST be an
activity; such as escaped with a one-hour, department meeting from 8:00 AM to 9:00
AM, tomorrow. Generally, these events will take up time on an
individual calendar. Hence, the event will appear as an opaque
interval BACKSLASH character (US-ASCII decimal
92). However, a COLON character in a search for busy time. Alternately, the event MAY have
its "TEXT" property value SHALL NOT
be escaped with a BACKSLASH character.Example: A multiple line value
of:

Project XYZ Final Review
Conference Room - 3B
Come Prepared.

would be represented as:

Project XYZ Final Review\n Conference Room - 3B\nCome Prepared.

4.3.12 Time Transparency set to "TRANSPARENT" in order

Value Name: TIME

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Purpose: This value type is used to prevent
blocking identify values that contain a
time of the event in searches for busy time. day.

Formal Definition: The "VEVENT" data type is also defined by the calendar component following
notation:

time = time-hour time-minute time-second [time-utc]

time-hour = 2DIGIT ;00-23
time-minute = 2DIGIT ;00-59
time-second = 2DIGIT ;00-60
;The "60" value is used to specify an
anniversary or daily reminder within a calendar. These events have a
DATE value type account for the "DTSTART" and "DTEND" properties instead of
the default data type of DATE-TIME. "leap" seconds.

time-utc = "Z"

Description: If such a "VEVENT" has an end
time, it MUST the property permits, multiple "time" values can be
specified as using a DATE COMMA character (US-ASCII decimal 44) separator
character. No additional content value also. encoding (i.e., BACKSLASH
character encoding) is defined for this value type.

The anniversary "TIME" data type
of "VEVENT" MAY span more than one date (i.e, "DTEND" property value is set used to identify values that contain a calendar date after the "DTSTART" property value). time
of day. The "DTSTART" property format is based on the [ISO 8601] complete
representation, basic format for a "VEVENT" specifies the inclusive start time of day. The text format
consists of a two-digit 24-hour of the event. For recurring events, it also specifies the very first
instance day (i.e., values 0-23), two-
digit minute in the recurrence set. hour (i.e., values 0-59), and two-digit seconds
in the minute (i.e., values 0-60). The "DTEND" property seconds value of 60 is only to
be used to account for "leap" seconds. Fractions of a "VEVENT"
calendar component specifies second are not
supported by this format.

In parallel to the non-inclusive end of "DATE-TIME" definition above, the event. For
cases where a "VEVENT" calendar component specifies a "DTSTART"
property with a DATE "TIME" data type but no "DTEND" property, the events
non-inclusive end is the end
expresses time values in three forms:

The form of the calendar date specified by the
"DTSTART" property. time with UTC offset MUST NOT be used. For cases where example, the
following is NOT VALID for a "VEVENT" calendar component
specifies time value:

230000-0800 ;Invalid time format

FORM #1 LOCAL TIME

The local time form is simply a "DTSTART" property with time value that does not contain the
UTC designator nor does it reference a DATE-TIME data time zone. For example, 11:00
PM:

230000

Time values of this type but no
"DTEND" property, the event ends on the same calendar date are said to be "floating" and are not bound
to any time
of day specified by the "DTSTART" property.

The "VEVENT" calendar component MUST include zone in particular. They are used to represent the "DTSTAMP",
"DTSTART", "SUMMARY" same
hour, minute, and "UID" properties. In addition, it MUST
include the "SEQUENCE" property, if it's second value regardless of which time zone is greater than zero.

The "VEVENT" calendar component cannot
currently being observed. For example, an event can be nested within another
calendar component. The "VEVENT" calendar components MAY defined that
indicates that an individual will be related
to each other or busy from 11:00 AM to 1:00 PM
every day, no matter which time zone the person is in. In these
cases, a "VTODO" or "VJOURNAL" calendar component local time can be specified. The recipient of an iCalendar
object with a property value consisting of a local time, without any
relative time zone information, should interpret the "RELATED-TO" property. value as being

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Example:

fixed to whatever time zone the ATTENDEE is in at any given moment.
This means that two ATTENDEEs may participate in the same event at
different UTC times; floating time should only be used where that is
reasonable behavior.

In most cases, a fixed time is desired. To properly communicate a
fixed time in a property value, either UTC time or local time with
time zone reference MUST be specified.

The following use of local time in a TIME value without the TZID property
parameter is an example to be interpreted as a local time value, regardless of
the "VEVENT" existence of "VTIMEZONE" calendar
component used to represent components in the iCalendar
object.

FORM #2: UTC TIME

UTC time, or absolute time, is identified by a meeting that will also LATIN CAPITAL LETTER Z
suffix character (US-ASCII decimal 90), the UTC designator, appended
to the time value. For example, the following represents 07:00 AM
UTC:

070000Z

The TZID property parameter MUST NOT be opaque applied to
searches for busy time:

BEGIN:VEVENT
UID:19970901T130000Z-123401@host.com
DTSTAMP:19970901T1300Z
DTSTART:19970903T163000Z
DTEND:19970903T190000Z
SUMMARY:Annual Employee Review
CLASS:PRIVATE
CATEGORIES:BUSINESS,HUMAN RESOURCES
END:VEVENT TIME properties
whose time values are specified in UTC.

FORM #3: LOCAL TIME AND TIME ZONE REFERENCE

The following local time with reference to time zone information form is an example of
identified by the "VEVENT" calendar component used
to represent a reminder that will not be opaque, but rather
transparent, use the TZID property parameter to searches for busy time:

BEGIN:VEVENT
UID:19970901T130000Z-123402@host.com
DTSTAMP:19970901T1300Z
DTSTART:19970401T163000Z
DTEND:19970402T010000Z
SUMMARY:Laurel reference the
appropriate time zone definition. TZID is discussed in sensitivity awareness class.
CLASS:PUBLIC
CATEGORIES:BUSINESS,HUMAN RESOURCES
TRANSP:TRANSPARENT
END:VEVENT detail in the
section on Time Zone.

Example: The following is an example represents 8:30 AM in New York in Winter, five
hours behind UTC, in each of the "VEVENT" calendar component three formats using the "X-
TIMEOFDAY" non-standard property:

X-TIMEOFDAY:083000

X-TIMEOFDAY:133000Z

X-TIMEOFDAY;TZID=America-New York:083000

4.3.13 URI

Value Name: URI

Purpose: This value type is used to represent an anniversary identify values that will occur annually. Since it takes
up no time, it will not appear as opaque in contain a search for busy time;
no matter what the value
uniform resource identifier (URI) type of reference to the "TRANSP" property indicates:

BEGIN:VEVENT
UID:19970901T130000Z-123403@host.com
DTSTAMP:19970901T1300Z
DTSTART:19971102
SUMMARY:Our Blissful Anniversary
CLASS:CONFIDENTIAL
CATEGORIES:ANNIVERSARY,PERSONAL,SPECIAL OCCASION
RRULE:FREQ=YEARLY
END:VEVENT

4.6.2 To-do Component

Component Name: VTODO

Purpose: Provide a grouping of calendar properties that describe a
to-do.
value.

Formal Definition: A "VTODO" calendar component is defined by the
following notation:

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todoc = "BEGIN" ":" [WSP] "VTODO" CRLF
todoprop *alarmc
"END" ":" [WSP] "VTODO" CRLF

todoprop = *attach *attendee *categories [class] *comment
[completed] *contact [created] [description] dtstamp
[dtstart] [due / duration] *exdate *exrule [geo]
[last-mod] [location] [organizer] [percent] priority
[rstatus] *related *resources *rdate *rrule
[recurid] [seq] [status] summary uid [url]

Description: A "VTODO" calendar component The data type is a grouping of component
properties and an OPTIONAL "VALARM" calendar component defined by the following
notation:

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uri = <As defined by any IETF RFC>

Description: This data type might be used to reference binary
information, for values that represent
an action-item are large, or assignment. For example, it MAY be an item of work
assigned otherwise undesirable to an individual; such as "turn in travel expense today".

The "VTODO" calendar component MUST
include directly in the "DTSTAMP",
"PRIORITY", "SUMMARY" iCalendar object.

The URI value formats in RFC 1738, RFC 2111 and "UID" properties. In addition, it MUST
include the "SEQUENCE" property, if it's any other IETF
registered value is greater than zero.

The "VTODO" calendar component cannot format can be nested within another
calendar component. If "VTODO" calendar components need to specified.

Any IANA registered URI format can be related
to each other or to used. These include, but are
not limited to, those defined in RFC 1738 and RFC 2111.

When a "VTODO" or "VJOURNAL" calendar component, they
can specify property parameter value is a relationship with the "RELATED-TO" property.

A "VTODO" calendar component without URI value type, the "DTSTART" and "DUE" (or
"DURATION") properties specifies URI must be
specified as a to-do that is associated with each
successive calendar dates, until it quoted-string value.

No additional content value encoding (i.e., BACKSLASH character
encoding) is completed. defined for this value type.

Example: The following is an example of a "VTODO" calendar component:

BEGIN:VTODO
UID:19970901T130000Z-123404@host.com
DTSTAMP:19970901T1300Z
DTSTART:19970415T133000Z
DUE:19970416T045959Z
SUMMARY:1996 Income Tax Preparation
CLASS:CONFIDENTIAL
CATEGORIES:FAMILY,FINANCE
PRIORITY:1
STATUS:NEEDS-ACTION
END:VEVENT

4.6.3 Journal Component

Component The following is a URI for a network file:

http://host1.com/my-report.txt

4.3.14 UTC Offset

Value Name: VJOURNAL UTC-OFFSET

Purpose: Provide a grouping of component This value type is used to identify properties that describe a
journal entry. contain
an offset from UTC to local time.

Formal Definition: A "VJOURNAL" calendar component The data type is defined by the following
notation:

utc-offset = time-numzone ;As defined above in time data type

time-numzone = ("+" / "-") time-hour time-minute

Description: The PLUS SIGN character MUST be specified for positive
UTC offsets (i.e., ahead of UTC). The value of "-0000" is not
allowed.

No additional content value encoding (i.e., BACKSLASH character
encoding) is defined for this value type.

Example: The following are UTC offsets are given for standard time
for New York (five hours behind UTC) and Geneva (one hour ahead of
UTC):

-0500

+0100

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journalc

4.4 iCalendar Object

The Calendaring and Scheduling Core Object is a collection of
calendaring and scheduling information. Typically, this information
will consist of a single iCalendar object. However, multiple
iCalendar objects can be sequentially grouped together. The first
line and last line of the iCalendar object MUST contain a pair of
iCalendar object delimiter strings. The syntax for an iCalendar
object is as follows:

icalobject = "BEGIN" ":" [WSP] "VJOURNAL" "VCALENDAR" CRLF
jourprop
icalbody
"END" ":" [WSP] "VJOURNAL" "VCALENDAR" CRLF

jourprop = *attach *attendee *categories [class] *comment
*contact [created] description dtstart dtstamp
*exdate *exrule [last-mod] [organizer] [recurid]
*related *rdate *rrule [rstatus] [seq] summary
uid [url]

Description: [icalobject]

The following is a simple example of an iCalendar object:

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//hacksw/handcal//NONSGML v1.0//EN
BEGIN:VEVENT
DTSTART:19970714T170000Z
DTEND:19970715T035959Z
SUMMARY:Bastille Day Party
END:VEVENT
END:VCALENDAR

4.5 Property

A "VJOURNAL" calendar component property is a grouping the definition of
component properties that represent one an individual attribute describing a
calendar property or more descriptive text
notes on a particular calendar date. The "DTSTART" component. A property is used
to specify takes the calendar date that form
defined by the journal entry "contentline" notation defined in section 4.1.1.

The following is associated
with. Generally, it will have a DATE value data type, but it MAY also
be used to specify a DATE-TIME value data type. Examples an example of a journal
entry include a daily record property:

DTSTART:19960415T133000Z

This memo places no imposed ordering of a legislative properties within an
iCalendar object.

Property names, parameter names and enumerated parameter values are
case insensitive. For example, the property name "DUE" is the same as
"due" and "Due", DTSTART;TZID=Eastern:19980714T120000 is the same as
DtStart;TzID=Eastern:19980714T120000.

4.6 Calendar Components

The body or a journal entry of individual telephone contacts for the day or an ordered list iCalendar object consists of
accomplishments for the day. a sequence of calendar
properties and one or more calendar components. The "VJOURNAL" calendar component can
also be used
properties are attributes that apply to associate the calendar as a document with whole. The
calendar components are collections of properties that express a
particular calendar date.

The "VJOURNAL" semantic. For example, the calendar component does not take up time on can
specify an event, a
calendar. Hence, it does not play to-do, a role in free or busy journal entry, time
searches - - it is as though it has a zone information, or
free/busy time transparency value of
TRANSPARENT. It is transparent to any such searches. information, or an alarm.

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The "VJOURNAL" calendar body of the iCalenar object is defined by the following notation:

icalbody = calprops component MUST

calprops = [calscale] [method] prodid version *x-prop

component = 1*(eventc / todoc / journalc / freebusyc /
/ timezonec / iana-comp / x-comp)

iana-comp = "BEGIN" ":" iana-token CRLF

1*contentline

"END" ":" iana-token CRLF

x-comp = "BEGIN" ":" x-name CRLF

1*contentline

"END" ":" x-name CRLF

An iCalendar object must include the "DTSTAMP",
"DTSTART", "DESCRIPTION", "SUMMARY" an "UID" "PRODID" and "VERSION" calendar
properties. In addition, it MUST must include the "SEQUENCE" property, if it's value is greater
than zero.

The "VJOURNAL" calendar component cannot be nested within another at least one calendar
component. If "VJOURNAL" calendar components need to be
related to each other or Special forms of iCalendar objects are possible to publish
just busy time (i.e., only a "VEVENT" "VFREEBUSY" calendar component) or "VTODO" time
zone (i.e., only a "VTIMEZONE" calendar component,
they can specify component) information. In
addition, a relationship with the "RELATED-TO" property.

Example: The following complex iCalendar object is an example of the "VJOURNAL" calendar
component:

BEGIN:VJOURNAL
UID:19970901T130000Z-123405@host.com
DTSTAMP:19970901T1300Z
DTSTART;VALUE=DATE:19970317
SUMMARY:Staff meeting minutes
DESCRIPTION:1. Staff meeting: Participants include Joe\, Lisa
and Bob. Aurora project plans were reviewed. There possible that is currently
no budget reserves for this project. Lisa will escalate to
management. Next meeting on Tuesday.
2. Telephone Conference: ABC Corp. sales representative called
to discuss new printer. Promised used to get us
capture a demo by Friday.
3. Henry Miller (Handsoff Insurance): Car was totaled by tree.
Is looking into complete snapshot of the contents of a loaner car. 654-2323 (tel).
END:VJOURNAL

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4.6.4 Free/Busy calendar (e.g.,
composite of many different calendar components). More commonly, an
iCalendar object will consist of just a single "VEVENT", "VTODO" or
"VJOURNAL" calendar component.

4.6.1 Event Component

Component Name: VFREEBUSY "VEVENT"

Purpose: Provide a grouping of component properties that describe
either a request for free/busy time, describe a response to a request
for free/busy time or describe a published set of busy time.

Formal an
event.

Format Definition: A "VFREEBUSY" "VEVENT" calendar component is defined by the
following notation:

freebusyc

eventc = "BEGIN" ":" [WSP] "VFREEBUSY" "VEVENT" CRLF
fbprop
eventprop *alarmc
"END" ":" [WSP] "VFREEBUSY" "VEVENT" CRLF

fbprop = fbrequest / fbreply / busytime

fbrequest

eventprop = 1*attendee dtstart dtend [duration] *attach *attendee *categories [class] *comment dtstamp
[last-mod] [seq] uid
;This set of properties is used for free/busy time request.

fbreply = 1*attendee
*contact [created] *comment [dtstart dtend] dtstamp
1*freebusy [description] [dtend / duration]
[dtstart] *exdate *exrule [geo] [last-mod] [rstatus] [location]
[organizer] [priority] *rstatus *related *resources
*rdate *rrule [dtstamp] [seq] uid
[url]
;This set of properties is used for free/busy time reply.

busytime = attendee dtstamp dtstart dtend *comment 1*freebusy [status] [summary]
[transp] [uid] [url] [recurid] *x-prop

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Description: A "VFREEBUSY" "VEVENT" calendar component is a grouping of component properties
properties, and possibly including "VALARM" calendar components, that
represents either a request for, scheduled amount of time on a reply calendar. For example, it
can be an activity; such as a one-hour long, department meeting from
8:00 AM to 9:00 AM, tomorrow. Generally, an event will take up time
on an individual calendar. Hence, the event will appear as an opaque
interval in a request search for free or busy time information or a published time. Alternately, the event can have
its Time Transparency set of
busy time information.

When used to request free/busy time information, the "VFREEBUSY"
calendar component MUST include the "ATTENDEE", "DTSTAMP", "DTSTART",
"DTEND", and "UID" properties. In addition, it MUST include "TRANSPARENT" in order to prevent
blocking of the
"SEQUENCE" property, if it's value event in searches for busy time.

The "VEVENT" is greater than zero.

When also the calendar component used to reply to specify an
anniversary or daily reminder within a request calendar. These events have a
DATE value type for free/busy time, the "VFREEBUSY"
calendar component MUST include "DTSTART" property instead of the "ATTENDEE", "DTSTAMP",
"FREEBUSY", and "UID" properties. In addition, default
data type of DATE-TIME. If such a "VEVENT" has a "DTEND" property, it
MUST include the
"SEQUENCE" property, if it's be specified as a DATE value is greater also. The anniversary type of
"VEVENT" can span more than zero.

When used one date (i.e, "DTEND" property value is
set to publish busy time, the "VFREEBUSY" a calendar component
MUST include date after the "ATTENDEE", "DTSTAMP", "DTSTART", "DTEND",
"FREEBUSY" properties. "DTSTART" property value).

The "VFREEBUSY" "DTSTART" property for a "VEVENT" specifies the inclusive start
of the event. For recurring events, it also specifies the very first
instance in the recurrence set. The "DTEND" property for a "VEVENT"
calendar component cannot be nested within another
calendar component. Multiple "VFREEBUSY" calendar components MAY be
specified within an iCalendar object. This permits specifies the grouping of
Free/Busy information into logical collections, such as monthly
groups non-inclusive end of busy time information.

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The "VFREEBUSY" the event. For
cases where a "VEVENT" calendar component is intended for use in iCalendar
object methods involving requests for free time, requests for busy
time, requests for both free and busy, and specifies a "DTSTART"
property with a DATE data type but no "DTEND" property, the associated replies.

Free/Busy information can be expressed using events
non-inclusive end is the "FREEBBUSY"
property. This property provides a terse representation end of time
periods. One or more "FREEBUSY" properties MAY be specified in the
"VFREEBUSY" calendar component to describe date specified by the Free/Busy information.

When present in
"DTSTART" property. For cases where a "VFREEBUSY" "VEVENT" calendar component, the "DTSTART" and
"DTEND" properties SHOULD be specified prior to any "FREEBUSY"
properties. In component
specifies a free time request, these properties MAY be used in
combination with the "DURATION" "DTSTART" property to express a request for with a
duration of free DATE-TIME data type but no
"DTEND" property, the event ends on the same calendar date and time within a given window
of time. day specified by the "DTSTART" property.

The recurrence properties ("RRULE", "EXRULE", "RDATE", "EXDATE") are
not permitted "VEVENT" calendar component cannot be nested within a "VFREEBUSY" another
calendar component. Any recurring
events are resolved into their individual busy time periods using However, "VEVENT" calendar components can be
related to each other or to a "VTODO" or to a "VJOURNAL" calendar
component with the
"FREEBUSY" "RELATED-TO" property.

Example: The following is an example of a "VFREEBUSY" the "VEVENT" calendar
component used to request free or busy time information:

BEGIN:VFREEBUSY
ORGANIZER:MAILTO:jane_doe@host1.com
ATTENDEE:MAILTO:john_public@host2.com
DTSTART:19971015T050000Z
DTEND:19971016T050000Z
DTSTAMP:19970901T083000Z
SEQUENCE:0
UID:19970901T0830000-uid1@host1.com
END:VFREEBUSY

The following is an example of represent a "VFREEBUSY" calendar component used
to reply meeting that will also be opaque to the request with busy time information:

BEGIN:VFREEBUSY
ATTENDEE:MAILTO:john_public@host2.com
DTSTAMP:19970901T100000Z
SEQUENCE:0
UID:19970901T0830000-uid1@host1.com
FREEBUSY;VALUE=PERIOD:19971015T050000Z/PT8H30M,
19971015T160000Z/PT5H30M,19971015T223000Z/PT6H30M
URL:http://host2.com/pub/busy/jpublic-01.vcs
COMMENT:This iCalendar file contains busy time information
searches for
the next three months.
END:VFREEBUSY busy time:

The following is an example of a "VFREEBUSY" the "VEVENT" calendar component used
to published represent a reminder that will not be opaque, but rather
transparent, to searches for busy time information.

BEGIN:VFREEBUSY
ATTENDEE:jsmith@host.com
DTSTART:19980313T141711Z time:

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DTEND:19980410T141711Z
FREEBUSY:19980314T233000Z/19980315T003000Z
FREEBUSY:19980316T153000Z/19980316T163000Z
FREEBUSY:19980318T030000Z/19980318T040000Z
URL:http://www.host.com/calendar/busytime/jsmith.ifb
END:VFREEBUSY

4.6.5 Timezone

BEGIN:VEVENT
UID:19970901T130000Z-123402@host.com
DTSTAMP:19970901T1300Z
DTSTART:19970401T163000Z
DTEND:19970402T010000Z
SUMMARY:Laurel is in sensitivity awareness class.
CLASS:PUBLIC
CATEGORIES:BUSINESS,HUMAN RESOURCES
TRANSP:TRANSPARENT
END:VEVENT

The following is an example of the "VEVENT" calendar component used
to represent an anniversary that will occur annually. Since it takes
up no time, it will not appear as opaque in a search for busy time;
no matter what the value of the "TRANSP" property indicates:

4.6.2 To-do Component

Component Name: VTIMEZONE VTODO

Purpose: Provide a grouping of component calendar properties that defines describe a
time zone.
to-do.

Formal Definition: A "VTIMEZONE" "VTODO" calendar component is defined by the
following notation:

timezonec = "BEGIN" ":" [WSP] "VTIMEZONE" CRLF

tzid [last-mod] [tzurl] 1*(standardc / daylightc)

"END" ":" [WSP] "VTIMEZONE" CRLF

standardc = "BEGIN" ":" [WSP] "STANDARD" CRLF

tzprop

"END" ":" [WSP] "STANDARD" CRLF

daylightc

todoc = "BEGIN" ":" [WSP] "DAYLIGHT" "VTODO" CRLF

tzprop
todoprop *alarmc
"END" ":" [WSP] "DAYLIGHT" "VTODO" CRLF

tzprop

todoprop = *attach *attendee *categories [class] *comment dtstart [rdate
[completed] *contact [created] [description] [dtstamp]
[dtstart] [due / rrule]

*tzname tzoffsetto tzoffsetfrom duration] *exdate *exrule [geo]
[last-mod] [location] [organizer] [percent] [priority]
*rstatus *related *resources *rdate *rrule
[recurid] [seq] [status] [summary] [uid] [url]
*x-prop

Description: A time zone "VTODO" calendar component is unambiguously defined by the set of time
measurement rules determined by the governing body for a given
geographic area. These rules describe at a minimum the base offset
from UTC for the time zone, often referred to as the Standard Time
offset. Many locations adjust their Standard Time forward grouping of component
properties and possibly "VALARM" calendar components that represent
an action-item or
backward by one hour, in order assignment. For example, it can be used to accommodate seasonal changes in
number
represent an item of daylight hours, often referred work assigned to as Daylight Saving Time.
Some locations adjust their time by a fraction of an hour. Standard
Time is also known as Winter Time. Daylight Saving Time is also
known individual; such as Advanced Time, Summer Time, or Legal Time in certain
countries. The following table shows the changes "turn in time zone rules
for the eastern United States starting from 1967. Each line
represents a description or rule for a particular observance.

Effective Observance Rule
travel expense today".

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Date (Date/Time) Offset Abbreviation

1967-* lastSun in Oct, 02:00 -0500 EST

1967-1973 last Sun in Apr, 02:00 -0400 EDT

1974-1974 Jan 6, 02:00 -0400 EDT

1975-1975 Feb 23, 02:00 -0400 EDT

1976-1986 last Sun in Apr, 02:00 -0400 EDT

1987-* first Sun in Apr, 02:00 -0400 EDT

Interoperability between two calendaring and scheduling applications,
especially for recurring events, to-dos

The "VTODO" calendar component cannot be nested within another
calendar component. However, "VTODO" calendar components can be
related to each other or journal entries, is
dependent on the ability to capture and convey date and time
information in an unambiguous format. The specification of current
time zone information is integral a "VTODO" or to this behavior.

If present, a "VJOURNAL" calendar
component with the "VTIMEZONE" "RELATED-TO" property.

A "VTODO" calendar component defines without the set of
Standard Time "DTSTART" and Daylight Saving Time observances "DUE" (or rules) for
"DURATION") properties specifies a to-do that will be associated with
each successive calendar date, until it is completed.

Example: The following is an example of a
particular time zone for "VTODO" calendar component:

4.6.3 Journal Component

Component Name: VJOURNAL

Purpose: Provide a given interval grouping of time. The "VTIMEZONE"
calendar component cannot be nested within other properties that describe a
journal entry.

Formal Definition: A "VJOURNAL" calendar components.
Multiple "VTIMEZONE" component is defined by the
following notation:

journalc = "BEGIN" ":" "VJOURNAL" CRLF
jourprop
"END" ":" "VJOURNAL" CRLF

jourprop = *attach *attendee *categories [class] *comment
*contact [created] [description] [dtstart] [dtstamp]
*exdate *exrule [last-mod] [organizer] [recurid]
*related *rdate *rrule *rstatus [seq] [status]
[summary] [uid] [url] *x-prop

Description: A "VJOURNAL" calendar components MAY exist in an iCalendar
object. In this situation, each "VTIMEZONE" MUST represent a unique
time zone definition. This component is necessary for some classes a grouping of events,
such as airline flights,
component properties that start in represent one time zone and end in
another.

The "VTIMEZONE" or more descriptive text
notes associated with a particular calendar component MUST be present if date. The "DTSTART"
property is used to specify the iCalendar
object contains an RRULE calendar date that generates dates on both sides of a time
zone shift (e.g. both in Standard Time and Daylight Saving Time)
UNLESS the iCalendar object intends journal entry
is associated with. Generally, it will have a DATE value data type,
but it can also be used to convey specify a floating time (See
the section "4.1.10.11 Time" DATE-TIME value data type.
Examples of a journal entry include a daily record of a legislative
body or a journal entry of individual telephone contacts for proper interpretation the day
or an ordered list of floating
time). It MAY be present if accomplishments for the iCalendar object day. The "VJOURNAL"
calendar component can also be used to associate a document with a
calendar date.

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The "VJOURNAL" calendar component does not contain
such take up time on a RRULE. In addition, if
calendar. Hence, it does not play a RRULE role in free or busy time
searches - - it is present, there must be valid as though it has a time zone information for all recurrence instances. transparency value of
TRANSPARENT. It is transparent to any such searches.

The "VTIMEZONE" "VJOURNAL" calendar component MUST include the "TZID" property
and at least one definition of a standard or daylight cannot be nested within another
calendar component. The
standard or daylight component MUST include the "DTSTART",
"TZOFFSETFROM" and "TZOFFSETTO" properties.

Each "VTIMEZONE" However, "VJOURNAL" calendar component consists of components can be
related to each other or to a collection of one "VEVENT" or more sub-components that describe to a "VTODO" calendar
component, with the rule "RELATED-TO" property.

Example: The following is an example of the "VJOURNAL" calendar
component:

BEGIN:VJOURNAL
UID:19970901T130000Z-123405@host.com
DTSTAMP:19970901T1300Z
DTSTART;VALUE=DATE:19970317
SUMMARY:Staff meeting minutes
DESCRIPTION:1. Staff meeting: Participants include Joe\, Lisa
and Bob. Aurora project plans were reviewed. There is currently
no budget reserves for this project. Lisa will escalate to
management. Next meeting on Tuesday.\n
2. Telephone Conference: ABC Corp. sales representative called
to discuss new printer. Promised to get us a particular
observance (either a Standard Time or demo by Friday.\n
3. Henry Miller (Handsoff Insurance): Car was totaled by tree.
Is looking into a Daylight Saving Time
observance). The "STANDARD" sub-component consists of loaner car. 654-2323 (tel).
END:VJOURNAL

4.6.4 Free/Busy Component

Component Name: VFREEBUSY

Purpose: Provide a collection grouping of component properties that describe Standard Time. The "DAYLIGHT" sub-component
consists of
either a collection of properties that describe Daylight Saving
Time. In general this collection of properties consists of:

- the first onset date-time for the observance

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- the last onset date-time request for the observance, if free/busy time, describe a last onset
is known.

- the offset response to be applied for the observance

- a rule that describes the day and time when the observance
takes effect

- an optional name request
for the observance

For a given free/busy time zone, there may be multiple unique definitions of
the observances over a period of time. Each observance is described
using either a "STANDARD" or "DAYLIGHT" sub-component. The collection
of these sub-components is used to describe the time zone for a given
period published set of busy time. The offset to apply at any given time is found by
locating the observance that has the last onset date and time before
the time in question, and using the offset value from that
observance.

The top-level properties in a "VTIMEZONE" calendar component are:

The mandatory "TZID" property is a text value that uniquely
identifies the VTIMZONE

Formal Definition: A "VFREEBUSY" calendar component within the scope of an
iCalendar object.

The optional "LAST-MODIFIED" property is a UTC value that specifies
the date and time that this time zone definition was last updated.

The optional "TZURL" property defined by the
following notation:

freebusyc = "BEGIN" ":" "VFREEBUSY" CRLF
fbprop
"END" ":" "VFREEBUSY" CRLF

fbprop = *attendee *comment [contact] [dtstart] [dtend]
[duration] [dtstamp] *freebusy [organizer] *rstatus
[uid] [url] *x-prop

Description: A "VFREEBUSY" calendar component is url value that points to a published
VTIMEZONE definition.

The collection grouping of
component properties that are used represents either a request for, a reply to define the STANDARD and
DAYLIGHT sub-components include:

The mandatory "DTSTART" property gives the effective onset date and
local time
a request for the free or busy time zone sub-component definition. "DTSTART" in
this usage MUST be specified as information or a local DATE-TIME value.

The mandatory "TZOFFSETFROM" property gives the UTC offset which is
in use when the onset published set of this
busy time zone observance begins.
"TZOFFSETFROM" is combined with "DTSTART" information.

When used to define the effective
onset for the time zone sub-component definition. For example, the
following represents the request free/busy time at which the observance of Standard
Time took effect in 1967 for information, the eastern United States:

DTSTART:19671029T020000

TZOFFSETFROM:-0400

The mandatory "TZOFFSETTO " "ATTENDEE"
property gives the UTC offset for specifies the calendar users whose free/busy time zone sub-component (Standard Time or Daylight Saving Time) when
this observance is in use. being

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The optional "TZNAME"

requested; the "ORGANIZER" property specifies the calendar user who
is requesting the customary name for free/busy time; the "DTSTART" and "DTEND"
properties specify the window of time
zone. It may be that the free/busy time is
being requested; the "UID" and "DTSTAMP" properties are specified multiple times, to allow for specifying
multiple language variants
assist in proper sequencing of the multiple free/busy time zone names. This could be requests.

When used to reply to a request for displaying dates.

If specified, free/busy time, the onset for "ATTENDEE"
property specifies the observance defined by calendar user responding to the free/busy time zone
sub-component is defined by either
request; the "RRULE" or "RDATE" property.
If neither are specified, only one sub-component can be specified in "ORGANIZER" property specifies the "VTIMEZONE" calendar component and it is assumed user that
originally requested the single
observance specified is always in effect.

The "RRULE" property defines the recurrence rule for free/busy time; the onset of "FREEBUSY" property
specifies the
observance defined by this free/busy time zone sub-component. Some specific
requirements for information; and the usage of RRULE for this purpose:

- If observance is known "UID" and "DTSTAMP"
properties are specified to have an effective end date, the
"UNTIL" recurrence rule parameter MUST be assist in proper sequencing of multiple
free/busy time replies.

When used to specify publish busy time, the
last valid onset of this observance (i.e., "ORGANIZER" property specifies
the UNTIL date-time
will be equal to calendar user associated with the last instance generated by published busy time; the recurrence
pattern). It MUST be specified as a full DATE-TIME value, using
local
"DTSTART" and "DTEND" properties specify an inclusive time plus window
that surrounds the UTC offset.

- The local busy time and UTC offset values provided in information; the "DTSTART" "FREEBUSY" property for
specifies the given observance MUST be used when generating published busy time information; and the onset date-time values (instances) from "DTSTAMP"
property specifies the RRULE. date/time that iCalendar object was created.

The "VFREEBUSY" calendar component cannot be nested within another
calendar component. Multiple "VFREEBUSY" calendar components can be
specified within an iCalendar object. This
interpretation permits the grouping of
Free/Busy information into logical collections, such as monthly
groups of the "DTSTART" UTC offset value busy time information.

The "VFREEBUSY" calendar component is specific to
"RRULE" usage intended for use in iCalendar
object methods involving requests for free time, requests for busy
time, requests for both free and busy, and the "VTIMEZONE" specification.

Alternatively, associated replies.

Free/Busy information is represented with the "RDATE" "FREEBBUSY" property.
This property MAY be used to define the onset provides a terse representation of time periods. One or
more "FREEBUSY" properties can be specified in the observance by giving "VFREEBUSY"
calendar component.

When present in a "VFREEBUSY" calendar component, the individual onset date "DTSTART" and times.
"RDATE" in this usage MUST
"DTEND" properties SHOULD be specified as prior to any "FREEBUSY"
properties. In a local DATE-TIME value free time request, these properties can be used in
combination with UTC offset.

The optional "COMMENT" the "DURATION" property is also allowed to represent a request for descriptive
explanatory text. a
duration of free time within a specified window of time.

The recurrence properties ("RRULE", "EXRULE", "RDATE", "EXDATE") are
not permitted within a "VFREEBUSY" calendar component. Any recurring
events are resolved into their individual busy time periods using the
"FREEBUSY" property.

Example: The following are examples is an example of the "VTIMEZONE" a "VFREEBUSY" calendar
component:

This
component used to request free or busy time information:

BEGIN:VFREEBUSY
ORGANIZER:MAILTO:jane_doe@host1.com
ATTENDEE:MAILTO:john_public@host2.com
DTSTART:19971015T050000Z

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DTEND:19971016T050000Z
DTSTAMP:19970901T083000Z
END:VFREEBUSY

The following is a simple an example showing of a "VFREEBUSY" calendar component used
to reply to the request with busy time information:

BEGIN:VFREEBUSY
ORGANIZER:MAILTO:jane_doe@host1.com
ATTENDEE:MAILTO:john_public@host2.com
DTSTAMP:19970901T100000Z
FREEBUSY;VALUE=PERIOD:19971015T050000Z/PT8H30M,
19971015T160000Z/PT5H30M,19971015T223000Z/PT6H30M
URL:http://host2.com/pub/busy/jpublic-01.ifb
COMMENT:This iCalendar file contains busy time zone information for
the
Eastern United States using "RDATE" property. Note that this next three months.
END:VFREEBUSY

The following is only
suitable for an example of a recurring event that starts on or later than April 6,
1997 at 02:00:00 EST (i.e., the earliest effective transition date
and time) and ends no later than April 7, 1998 02:00:00 EST (i.e.,
latest valid date and time for EST in this scenario). For example,
this can be "VFREEBUSY" calendar component used for
to published busy time information.

BEGIN:VFREEBUSY
ORGANIZER:jsmith@host.com
DTSTART:19980313T141711Z
DTEND:19980410T141711Z
FREEBUSY:19980314T233000Z/19980315T003000Z
FREEBUSY:19980316T153000Z/19980316T163000Z
FREEBUSY:19980318T030000Z/19980318T040000Z
URL:http://www.host.com/calendar/busytime/jsmith.ifb
END:VFREEBUSY

4.6.5 Time Zone Component

Component Name: VTIMEZONE

Purpose: Provide a recurring event grouping of component properties that occurs every Friday,
8am-9am, starting June 1, 1997, ending December 31, 1997.

BEGIN:VTIMEZONE
TZID:America-New_York
LAST-MODIFIED:19870101T000000Z
BEGIN:STANDARD
DTSTART:19971026T020000
RDATE:19971026T020000 defines a
time zone.

Formal Definition: A "VTIMEZONE" calendar component is defined by the
following notation:

timezonec = "BEGIN" ":" "VTIMEZONE" CRLF

tzid [last-mod] [tzurl] 1*(standardc / daylightc)
*x-prop

"END" ":" "VTIMEZONE" CRLF

standardc = "BEGIN" ":" "STANDARD" CRLF

tzprop

"END" ":" "STANDARD" CRLF

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TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19971026T020000
RDATE:19970406T020000
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE

This

daylightc = "BEGIN" ":" "DAYLIGHT" CRLF

tzprop

"END" ":" "DAYLIGHT" CRLF

tzprop = *comment dtstart (*rdate / *rrule)
*tzname tzoffsetto tzoffsetfrom *x-prop

Description: A time zone is a simple example showing unambiguously defined by the current set of time zone
measurement rules for determined by the
Eastern United States using governing body for a RRULE recurrence pattern. Note that
there is no effective end date given
geographic area. These rules describe at a minimum the base offset
from UTC for the time zone, often referred to either of as the Standard Time
offset. Many locations adjust their Standard Time forward or backward
by one hour, in order to accommodate seasonal changes in number of
daylight hours, often referred to as Daylight Time rules. This information would be valid for Saving Time. Some
locations adjust their time by a recurring
event starting today and continuing on into the fraction of an hour. Standard Time
is also known future.

BEGIN:VTIMEZONE
TZID:America-New_York
LAST-MODIFIED:19870101T000000Z
TZURL:http://zones.stds_r_us.net/tz/America-New_York
BEGIN:STANDARD
DTSTART:19671029T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19870405T020000
RRULE: FREQ=YEARLY;BYDAY=1SU;BYMONTH=4
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE

This as Winter Time. Daylight Saving Time is an example showing a fictitious set of also known as
Advanced Time, Summer Time, or Legal Time in certain countries. The
following table shows the changes in time zone rules for the Eastern eastern
United States, where the Daylight Time States starting from 1967. Each line represents a description
or rule has an effective end date
(i.e., after that date, Daylight Time is no longer observed).

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Effective Observance Rule

Date (Date/Time) Offset Abbreviation

1967-* lastSun in Oct, 02:00 -0500 EST

1967-1973 last Sun in Apr, 02:00 -0400 EDT

1974-1974 Jan 6, 1998

DTSTART:19870405T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4;UNTIL=19980404T070000
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE

This 02:00 -0400 EDT

1975-1975 Feb 23, 02:00 -0400 EDT

1976-1986 last Sun in Apr, 02:00 -0400 EDT

1987-* first Sun in Apr, 02:00 -0400 EDT

Interoperability between two calendaring and scheduling applications,
especially for recurring events, to-dos or journal entries, is
dependent on the ability to capture and convey date and time
information in an example showing a fictitious set unambiguous format. The specification of rules for current
time zone information is integral to this behavior.

If present, the Eastern
United States, where "VTIMEZONE" calendar component defines the first Daylight set of
Standard Time rule has an effective
end date. There is a second and Daylight Saving Time rule that picks up where
the other left off.

BEGIN:VTIMEZONE
TZID:America-New_York
LAST-MODIFIED:19870101T000000Z
BEGIN:STANDARD
DTSTART:19671029T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19870405T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4;UNTIL=19980404T070000
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
BEGIN:DAYLIGHT
DTSTART:19990424T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=4
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE

4.6.6 Alarm Component

Component Name: VALARM

Purpose: Provide observances (or rules) for a grouping
particular time zone for a given interval of component properties that define an
alarm.

Formal Definition: A "VALARM" time. The "VTIMEZONE"
calendar component cannot be nested within other calendar components.
Multiple "VTIMEZONE" calendar components can exist in an iCalendar
object. In this situation, each "VTIMEZONE" MUST represent a unique
time zone definition. This is defined by the
following notation:

alarmc = "BEGIN" ":" [WSP] "VALARM" CRLF
(audioprop / dispprop / emailprop
/ procprop)
"END" ":" [WSP] "VALARM" CRLF necessary for some classes of events,
such as airline flights, that start in one time zone and end in
another.

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audioprop = alarmtype trigger [duration repeat] attach

dispprop = alarmtype description trigger [duration
repeat]

emailprop = alarmtype 1*attendee *attach description
trigger [duration repeat] summary

procprop = alarmtype attach [description] trigger [duration
repeat]

Description: A "VALARM"

The "VTIMEZONE" calendar component is MUST be present if the iCalendar
object contains an RRULE that generates dates on both sides of a time
zone shift (e.g. both in Standard Time and Daylight Saving Time)
unless the iCalendar object intends to convey a grouping floating time (See
the section "4.1.10.11 Time" for proper interpretation of component
properties that is floating
time). It can be present if the iCalendar object does not contain
such a reminder or alarm for an event or RRULE. In addition, if a to-do. For
example, it may RRULE is present, there must be used to define a reminder valid
time zone information for a pending event or
an overdue to-do. all recurrence instances.

The "VALARM" "VTIMEZONE" calendar component MUST include the "ALARM-TYPE" "TZID" property
and
"TRIGGER" properties. In addition, an AUDIO type at least one definition of alarm a standard or daylight component. The
standard or daylight component MUST include the "ATTACH" property to point to a digital sound resource to "DTSTART",
"TZOFFSETFROM" and "TZOFFSETTO" properties.

An individual "VTIMEZONE" calendar component MUST be played. The DISPLAY type specified for
each unique "TZID" parameter value specified in the iCalendar object.

Each "VTIMEZONE" calendar component consists of alarm MUST include a collection of one
or more sub-components that describe the "DESCRIPTION"
property. rule for a particular
observance (either a Standard Time or a Daylight Saving Time
observance). The EMAIL type "STANDARD" sub-component consists of alarm MUST include a collection of
properties that describe Standard Time. The "DAYLIGHT" sub-component
consists of a collection of properties that describe Daylight Saving
Time. In general this collection of properties consists of:

- the "ATTENDEE",
"DESCRIPTION" first onset date-time for the observance

- the last onset date-time for the observance, if a last onset
is known.

- the offset to be applied for the observance

- a rule that describes the day and "SUMMARY" properties. The PROCEDURE type of alarm
MUST include time when the "ATTACH" property to point to observance
takes effect

- an optional name for the observance

For a procedure resource
to given time zone, there may be invoked.

The "VALARM" calendar component MUST only appear within multiple unique definitions of
the observances over a period of time. Each observance is described
using either a
"VEVENT" "STANDARD" or "VTODO" calendar component. The "VALARM" calendar
components cannot be nested. Multiple "VALARM" calendar components
MAY be specified.

The "TRIGGER" property specifies when the alarm will be triggered. "DAYLIGHT" sub-component. The "TRIGGER" property specifies a duration prior collection
of these sub-components is used to describe the start of an
event or time zone for a to-do. given
period of time. The "TRIGGER" edge may be explicitly set to be
relative offset to apply at any given time is found by
locating the "START" or "END" of observance that has the event or to-do with last onset date and time before
the
"RELATED" parameter of time in question, and using the "TRIGGER" property. offset value from that
observance.

The "TRIGGER" top-level properties in a "VTIMEZONE" calendar component are:

The mandatory "TZID" property is a text value type MAY alternately be set to an absolute that uniquely
identifies the VTIMZONE calendar date and
time of day value.

In an alarm set to trigger on component within the "START" scope of an event or to-do,
iCalendar object.

The optional "LAST-MODIFIED" property is a UTC value that specifies
the
"DTSTART" date and time that this time zone definition was last updated.

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The optional "TZURL" property MUST be present in the associated event or to-do.
In an alarm in a "VEVENT" calendar component set is url value that points to trigger on the
"END" a published
VTIMEZONE definition.

The collection of the event, the "DTEND" or "DTSTART" and "DURATION" properties MUST be present. In an alarm in a "VTODO" calendar
component set that are used to trigger on define the "END" of STANDARD and
DAYLIGHT sub-components include:

The mandatory "DTSTART" property gives the to-do, effective onset date and
local time for the "DUE" or time zone sub-component definition. "DTSTART" and "DURATION" properties in
this usage MUST be present.

The alarm MAY be defined such that it triggers repetitively. A
definition of an alarm with specified as a repeating trigger MUST include both the
"DURATION" and "REPEAT" properties. local DATE-TIME value.

The "DURATION" mandatory "TZOFFSETFROM" property specifies gives the delay period, after UTC offset which is
in use when the alarm will repeat. The "REPEAT"
property specifies the number onset of additional repetitions that the
alarm will triggered. This count this time zone observance begins.
"TZOFFSETFROM" is in addition combined with "DTSTART" to define the initial
triggering of effective
onset for the alarm. Both time zone sub-component definition. For example, the
following represents the time at which the observance of these properties must be present Standard
Time took effect in
order to specify a repeating alarm. If one of these two properties

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are absent, then Fall 1967 for the alarm will not repeat beyond eastern United States:

DTSTART:19671029T020000

TZOFFSETFROM:-0400

The mandatory "TZOFFSETTO " property gives the initial
trigger. UTC offset for the
time zone sub-component (Standard Time or Daylight Saving Time) when
this observance is in use.

The "ALARM-TYPE" optional "TZNAME" property is used within the "VALARM" calendar
component to specify the type of customary name for the alarm. The "ALARM-TYPE" property
value of AUDIO specifies an alarm that triggers with an audio sound;
a value time
zone. It may be specified multiple times, to allow for specifying
multiple language variants of DISPLAY specifies an alarm that triggers with the
"Calendar User Agent" time zone names. This could be used
for displaying text; dates.

If specified, the value of EMAIL specifies
an alarm that triggers onset for the posting of an electronic email message to
one or more email addresses; and observance defined by the value of PROCEDURE specifies an
alarm that triggers time zone
sub-component is defined by either the execution of a procedure. The "ALARM-TYPE"
property MUST specify just "RRULE" or "RDATE" property.
If neither are specified, only one of these valid values. Multiple
categories of alarms MAY BE sub-component can be specified by defining more than one,
different categories of "VALARM" calendar components within a
"VEVENT" or "VTODO" calendar component.

In an AUDIO type of alarm, the "ATTACH" property in
the "VALARM" "VTIMEZONE" calendar component MUST specify an audio sound file that is intended
to be rendered as the alarm effect. If an "ATTACH" property and it is
specified assumed that does not refer to a digital sound resource, then no
audio alarm will be sounded. If the digital sound resource single
observance specified is always in a
format that cannot be rendered, then no audio alarm will be sounded.

In a DISPLAY type effect.

The "RRULE" property defines the recurrence rule for the onset of alarm, the "DESCRIPTION" property in
observance defined by this time zone sub-component. Some specific
requirements for the
"VALARM" calendar component usage of RRULE for this purpose include:

- If observance is intended known to have an effective end date, the
"UNTIL" recurrence rule parameter MUST be displayed as used to specify the alarm
effect. In an EMAIL category
last valid onset of alarm, this observance (i.e., the intended alarm effect is UNTIL date-time
will be equal to use the "DESCRIPTION" property last instance generated by the recurrence
pattern). It MUST be specified in UTC time.

- The "DTSTART" and the "VALARM" calendar component
as "TZOFFSETTO" properties MUST be used
when generating the body text of an email message that is to onset date-time values (instances) from the
RRULE.

Alternatively, the "RDATE" property can be sent used to define the
addresses specified onset
of the observance by any "ATTENDEE" properties present in giving the
"VALARM" calendar component. individual onset date and times.
"RDATE" in this usage MUST be specified as a local DATE-TIME value in
UTC time.

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The "SUMMARY" optional "COMMENT" property in is also allowed for descriptive
explanatory text.

Example: The following are examples of the "VALARM" "VTIMEZONE" calendar component
component:

This is intended to be used as an example showing time zone information for the subject text Eastern
United States using "RDATE" property. Note that this is only suitable
for a recurring event that starts on or later than April 6, 1997 at
03:00:00 EDT (i.e., the earliest effective transition date and time)
and ends no later than April 7, 1998 02:00:00 EST (i.e., latest valid
date and time for EST in this scenario). For example, this can be
used for the
email. Any "ATTACH" properties are sent as email attachments.

In a PROCEDURE type of alarm, recurring event that occurs every Friday, 8am-9:00 AM,
starting June 1, 1997, ending December 31, 1997.

BEGIN:VTIMEZONE
TZID:America-New_York
LAST-MODIFIED:19870101T000000Z
BEGIN:STANDARD
DTSTART:19971026T020000
RDATE:19971026T020000
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19971026T020000
RDATE:19970406T020000
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE

This is a simple example showing the "ATTACH" property in current time zone rules for the "VALARM"
calendar component MUST specify
Eastern United States using a procedure or program RRULE recurrence pattern. Note that
there is
intended no effective end date to be invoked as the alarm effect. If either of the procedure Standard Time or
program is in a format that cannot be rendered, then no procedure
alarm will
Daylight Time rules. This information would be invoked. If valid for a recurring
event starting today and continuing on into the "DESCRIPTION" property known future.

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TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE

This is present, its
value specifies the argument string to be passed to the procedure or
program. "Calendar User Agents" that receive an iCalendar object with
this category example showing a fictitious set of alarm, should allow rules for the "Calendar User" to disable
or otherwise ignore this type of alarm. While Eastern
United States, where the Daylight Time rule has an effective end date
(i.e., after that date, Daylight Time is no longer observed).

BEGIN:VTIMEZONE
TZID:America-New_York
LAST-MODIFIED:19870101T000000Z
BEGIN:STANDARD
DTSTART:19671029T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19870405T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4;UNTIL=19980404T070000Z
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE

This is an example showing a very useful alarm
capability, the PROCEDURE type fictitious set of alarm should be treated by rules for the
"Calendar User Agent" as a potential security risk.

Example: The following example Eastern
United States, where the first Daylight Time rule has an effective
end date. There is for a "VALARM" calendar component
that specifies an audio alarm second Daylight Time rule that will sound at a precise time and
repeat 4 more times at 15 minute intervals:

BEGIN:VALARM
TRIGGER;VALUE=DATE-TIME:19970317T133000Z
REPEAT:4
DURATION:PT15M
ALARM-TYPE: AUDIO picks up where
the other left off.

BEGIN:VTIMEZONE
TZID:America-New_York
LAST-MODIFIED:19870101T000000Z
BEGIN:STANDARD
DTSTART:19671029T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19870405T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4;UNTIL=19980404T070000Z
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
BEGIN:DAYLIGHT
DTSTART:19990424T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=4

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ATTACH:ftp://host.com/pub/sounds/bell-01.wav
END:VALARM

The following example is for

TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE

4.6.6 Alarm Component

Component Name: VALARM

Purpose: Provide a grouping of component properties that define an
alarm.

Formal Definition: A "VALARM" calendar component that
specifies a display alarm that will trigger 15 minutes before the
scheduled start of the event or the due date/time of the to-do it is
associated with and will repeat 2 more times at 15 minute intervals:

BEGIN:VALARM
TRIGGER:PT30M
REPEAT:2
DURATION:PT15M
ALARM-TYPE:DISPLAY
DESCRIPTION:Breakfast meeting with executive\n
team at 8:30 AM EST.
END:VALARM

The defined by the
following example notation:

alarmc = "BEGIN" ":" "VALARM" CRLF
(audioprop / dispprop / emailprop / procprop)
"END" ":" "VALARM" CRLF

audioprop = action trigger [duration repeat] [attach] *x-prop

dispprop = action description trigger [duration
repeat] *x-prop

emailprop = action 1*attendee *attach description
trigger [duration repeat] summary *x-prop

procprop = action attach [description] trigger [duration
repeat] *x-prop

Description: A "VALARM" calendar component is a grouping of component
properties that is a reminder or alarm for an event or a to-do. For
example, it may be used to define a reminder for a pending event or
an overdue to-do.

The "VALARM" calendar component that
specifies an email alarm that will trigger 2 days before MUST include the
scheduled due date/time of a to-do it is associated with. It does not
repeat. "ACTION" and
"TRIGGER" properties. The email has a subject, body "ACTION" property further constrains the
"VALARM" calendar component in the following ways:

When the action is "AUDIO", the alarm can also include one and attachment link.

BEGIN:VALARM
TRIGGER:P2D
ALARM-TYPE:EMAIL
ATTENDEE:MAILTO:john_doe@host.com
SUMMARY:*** REMINDER: SEND AGENDA FOR WEEKLY STAFF MEETING ***
DESCRIPTION:A draft agenda needs to be sent out only
one "ATTACH" property, which MUST point to a sound resource, which is
rendered when the attendees
to alarm is triggered.

When the weekly managers meeting (MGR-LIST). Attached action is "DISPLAY", the alarm MUST also include a
pointer
"DESCRIPTION" property, which contains the document template for text to be displayed when
the agenda file.
ATTACH:http://host.com/templates/agenda.doc
END:VALARM

The following example alarm is for a "VALARM" calendar component that
specifies a procedural triggered.

When the action is "EMAIL", the alarm that will trigger at MUST include a precise date/time "DESCRIPTION"
property, which contains the text to be used as the message body, a
"SUMMARY" property, which contains the text to be used as the message
subject, and will repeat 23 one or more times at "ATTENDEE" properties, which contain the
email address of attendees to receive the message. It can also
include one hour intervals. The alarm will
invoke a procedure file.

BEGIN:VALARM
TRIGGER;VALUE=DATE-TIME:19980101T050000Z
REPEAT:23
DURATION:PT1H
ALARM-TYPE:PROCEDURE
ATTACH:ftp://host.com/novo-procs/felizano.exe
END:VALARM

4.7 Calendar Properties

The Calendar Properties or more "ATTACH" properties, which are attributes that apply intended to the iCalendar
object, as a whole. These properties do not appear within a calendar
component. They should be specified after the "BEGIN:VCALENDAR"
property and prior to any calendar component.

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4.7.1 Calendar Scale

Property Name: CALSCALE

Purpose: This property defines the calendar scale used for the
calendar information specified in

sent as message attachments. When the iCalendar object.

Value Type: TEXT

Conformance: Property MAY be specified in an iCalendar object. The
default value alarm is "GREGORIAN".

Description: This memo triggered, the email
message is based on sent.

When the Gregorian calendar scale. The
Gregorian calendar scale action is assumed if this property "PROCEDURE", the alarm MUST include one and only
one "ATTACH" property, which MUST point to a procedure resource,
which is not specified
in invoked when the iCalendar object. It alarm is expected that other triggered.

The "VALARM" calendar scales
will be defined in other specifications component MUST only appear within either a
"VEVENT" or by future versions of this
memo.

No property parameters MAY "VTODO" calendar component. "VALARM" calendar components
cannot be nested. Multiple mutually independent "VALARM" calendar
components can be specified on this property.

Format Definition: for a single "VEVENT" or "VTODO" calendar
component.

The "TRIGGER" property is defined by specifies when the following notation:

calscale = "CALSCALE" ":" [WSP] calvalue CRLF

calvalue = "GREGORIAN" / iana-token

Example: alarm will be triggered.
The following is an example of this property:

CALSCALE:GREGORIAN

4.7.2 Method

Property Name: METHOD

Purpose: This "TRIGGER" property defines specifies a duration prior to the start of an
event or a to-do. The "TRIGGER" edge may be explicitly set to be
relative to the iCalendar object method associated "START" or "END" of the event or to-do with the calendar object.

Value Type: TEXT

Conformance:
"RELATED" parameter of the "TRIGGER" property. The "TRIGGER" property MAY
value type can alternatively be specified in set to an iCalendar object.

Description: When used in a MIME message entity, absolute calendar date and
time of day value.

In an alarm set to trigger on the value "START" of this an event or to-do, the
"DTSTART" property MUST be present in the same as associated event or to-do.
In an alarm in a "VEVENT" calendar component set to trigger on the Content-Type "method" parameter
value. This property can only appear once within
"END" of the iCalendar
object. If event, either the "METHOD" "DTEND" property MUST be present, or
the Content-Type "method"
parameter is specified, then the other must also "DTSTART" and "DURATION" properties MUST both be specified.

No methods are defined by this specification. This is present. In an
alarm in a "VTODO" calendar component set to trigger on the subject "END" of
other specifications, such as
the iCalendar Transport-independent
Interoperability Protocol (iTIP) defined by [ITIP].

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If this to-do, either the "DUE" property is not present in MUST be present, or the iCalendar object, then no
scheduling transaction MAY
"DTSTART" and "DURATION" properties MUST both be assumed. In present.

The alarm can be defined such cases, the iCalendar
object is merely being used to transport a snapshot of some calendar
information; without the intention that it triggers repeatedly. A
definition of conveying an alarm with a scheduling
semantic.

No property parameters MAY be specified on this property.

Format Definition: repeating trigger MUST include both the
"DURATION" and "REPEAT" properties. The "DURATION" property is defined by specifies
the following notation:

method = "METHOD" ":" [WSP] method-value CRLF

method-value = iana-token

Example: delay period, after which the alarm will repeat. The following is a hypothetical example of this "REPEAT"
property to
convey specifies the number of additional repetitions that the iCalendar object is a request for a meeting:

METHOD:REQUEST

4.7.3 Product Identifier

Property Name: PRODID

Purpose:
alarm will triggered. This property specifies the identifier for repitition count is in addition to the product that
created
initial triggering of the iCalendar object.

Value Type: TEXT

Conformance: The property MUST alarm. Both of these properties must be specified
present in an iCalendar object
but can only appear once.

Description: The vendor order to specify a repeating alarm. If one of the implementation should assure that this these two
properties is a globally unique identifier; using some technique such as an ISO
9070 FPI value.

This property should absent, then the alarm will not be repeat beyond the
initial trigger.

The "ACTION" property is used within the "VALARM" calendar component
to alter specify the interpretation type of an
iCalendar object beyond action invoked when the semantics specified in this memo. For
example, it alarm is not triggered.
The "VALARM" properties provide enough information for a specific
action to be used to further invoked. It is typically the understanding responsibility of non-
standard properties.

No property parameters MAY be a
"Calendar User Agent" (CUA) to deliver the alarm in the specified on this property.

Format Definition: The
fashion. An "ACTION" property is defined by value of AUDIO specifies an alarm that
causes a sound to be played to alert the following notation:

prodid = "PRODID" ":" [WSP] pidvalue CRLF

pidvalue = text
;Any text user; DISPLAY specifies an
alarm that describes causes a text message to be displayed to the product user; EMAIL
specifies an alarm that causes an electronic email message to be
delivered to one or more email addresses; and version
;and PROCEDURE specifies an
alarm that is generally assured of being unique.

Example: causes a procedure to be executed. The following is an example "ACTION" property
MUST specify one and only one of this property:

PRODID:-//ABC Corporation//NONSGML My Product//EN these values.

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4.7.4 Version

Property Name: VERSION

Purpose: This

In an AUDIO alarm, if the optional "ATTACH" property specifies is included, it
MUST specify an audio sound resource. The intention is that the identifier corresponding sound
will be played as the alarm effect. If an "ATTACH" property is
specified that does not refer to a sound resource, or if the
highest version number
specified sound resource cannot be rendered (because its format is
unsupported, or because it cannot be retrieved), then the minimum and maximum range of CUA or
other entity responsible for playing the
iCalendar specification that sound may choose a fallback
action, such as playing a built-in default sound, or playing no sound
at all.

In a DISPLAY alarm, the intended alarm effect is required in order to interpret for the
iCalendar object.

Value Type: TEXT

Conformance: This property MUST be specified by in an iCalendar
object, but MAY only be specified once.

Description: A text value
of "2.0" corresponds to this memo.

No property parameters MAY be specified on this property.

Format Definition: The property is defined by the following notation:

version = "VERSION" ":" [WSP] vervalue CRLF

vervalue = "2.0" ;This memo
/ maxver
/ (minver ";" [WSP] maxver)

minver = <A IANA registered iCalendar version identifier>
;Minimum iCalendar version used "DESCRIPTION" property to be displayed to create the iCalendar object

maxver = <A IANA registered iCalendar version identifier>
;Maximum iCalendar version used to create user.

In an EMAIL alarm, the iCalendar object

Example: The following intended alarm effect is for an example of this property:

VERSION:2.0

4.8 Component Properties

The following properties MAY appear within calendar components, as email message
to be composed and delivered to all the addresses specified by each component property definition.

4.8.1 Descriptive Component Properties

The following the
"ATTENDEE" properties specify descriptive information about in the "VALARM" calendar components.

4.8.1.1 Attachment

Property Name: ATTACH

Purpose: component. The
"DESCRIPTION" property provides of the capability to associate a document
object with a "VALARM" calendar component.

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Value Type: The default value type for this component MUST be
used as the body text of the message, and the "SUMMARY" property is URI. The
value type MAY also MUST
be reset to BINARY used as the subject text. Any "ATTACH" properties in order the "VALARM"
calendar component SHOULD be sent as attachments to include inline
binary encoded content information.

Conformance: The the message.

In a PROCEDURE alarm, the "ATTACH" property MAY be specified in an iCalendar object.

Description: The property MAY only be specified within "VEVENT",
"VTODO", "VJOURNAL", or the "VALARM" calendar components. This
component MUST specify a procedure or program that is intended to be
invoked as the alarm effect. If the procedure or program is in a
format that cannot be rendered, then no procedure alarm will be
invoked. If the "DESCRIPTION" property
MAY is present, its value
specifies the argument string to be specified multiple times within passed to the procedure or
program. "Calendar User Agents" that receive an iCalendar object.

Only object with
this category of alarm, can disable or allow the "ENCODING" and "VALUE", property parameters MAY be specified
on "Calendar User" to
disable, or otherwise ignore this property.

Format Definition: The property is defined type of alarm. While a very useful
alarm capability, the PROCEDURE type of alarm should be treated by
the following notation:

attach = ("ATTACH" ":" [WSP] uri CRLF)

attach =/ ("ATTACH" ";" [WSP] "ENCODING" "=" "b" ";" [WSP]
"VALUE" "=" "text" ":" [WSP] binary "Calendar User Agent" as a potential security risk.

Example: The following are examples of this property:

ATTACH:CID:jsmith.part3.960817T083000.xyzMail@host1.com

ATTACH:FTP://xyzCorp.com/pub/reports/r-960812.ps

4.8.1.2 Categories

Property Name: CATEGORIES

Purpose: This property defines the categories example is for a "VALARM" calendar
component.

Value Type: TEXT

Conformance: component
that specifies an audio alarm that will sound at a precise time and
repeat 4 more times at 15 minute intervals:

BEGIN:VALARM
TRIGGER;VALUE=DATE-TIME:19970317T133000Z
REPEAT:4
DURATION:PT15M
ACTION:AUDIO
ATTACH:ftp://host.com/pub/sounds/bell-01.wav
END:VALARM

The property MAY only be specified within "VEVENT",
"VTODO" or "VJOURNAL" calendar components.

Description: This property following example is used to specify categories or subtypes
of the calendar component. The categories are useful in searching for a "VALARM" calendar component of that
specifies a particular type and category. Within display alarm that will trigger 30 minutes before the
"VEVENT", "VTODO" or "VJOURNAL" calendar components, more than one
category MAY be specified as a list
scheduled start of categories separated by the
COMMA character (ASCII decimal 44).

Only event or the "LANGUAGE" property parameters MAY be specified on this
property.

Format Definition: The property is defined by due date/time of the following notation:

categories = "CATEGORIES" [catparam] ":" [WSP] catvalue CRLF

catparam = ";" [WSP] languageparm to-do it is
associated with and will repeat 2 more times at 15 minute intervals:

BEGIN:VALARM
TRIGGER:PT30M
REPEAT:2
DURATION:PT15M

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catvalue = "ANNIVERSARY" / "APPOINTMENT" / "BUSINESS"
/ "EDUCATION" / "HOLIDAY" / "MEETING" / "MISCELLANEOUS"
/ "NON-WORKING HOURS" / "NOT IN OFFICE" / "PERSONAL"
/ "PHONE CALL" / "SICK DAY" / "SPECIAL OCCASION"
/ "TRAVEL" / "VACATION" / text
;These are just examples
;Used only in "VEVENT", "VTODO" and "VJOURNAL" calendar components.

Example:

ACTION:DISPLAY
DESCRIPTION:Breakfast meeting with executive\n
team at 8:30 AM EST.
END:VALARM

The following are examples of this property:

CATEGORIES:APPOINTMENT,EDUCATION

CATEGORIES:MEETING

4.8.1.3 Classification

Property Name: CLASS

Purpose: This property defines the access classification example is for a "VALARM" calendar component.

Value Type: TEXT

Conformance: The property MAY only be specified in a "VEVENT",
"VTODO" or "VJOURNAL" calendar components. The property MAY only be
specified once.

Description: An access classification is only one component of that
specifies an email alarm that will trigger 2 days before the
general security system within
scheduled due date/time of a calendar application. to-do it is associated with. It provides does not
repeat. The email has a
method of capturing subject, body and attachment link.

BEGIN:VALARM
TRIGGER:P2D
ACTION:EMAIL
ATTENDEE:MAILTO:john_doe@host.com
SUMMARY:*** REMINDER: SEND AGENDA FOR WEEKLY STAFF MEETING ***
DESCRIPTION:A draft agenda needs to be sent out to the scope of attendees
to the access weekly managers meeting (MGR-LIST). Attached is a
pointer the calendar owner
intends document template for information within an individual calendar entry. the agenda file.
ATTACH:http://host.com/templates/agenda.doc
END:VALARM

The
access classification of an individual iCalendar component following example is useful
when measured along with the other security components of for a "VALARM" calendar component that
specifies a procedural alarm that will trigger at a precise date/time
and will repeat 23 more times at one hour intervals. The alarm will
invoke a calendar
system (e.g., calendar user authentication, authorization, access
rights, access role, etc.). Hence, the semantics of the individual
access classifications cannot be completely defined by this memo
alone. Additionally, due procedure file.

BEGIN:VALARM
TRIGGER;VALUE=DATE-TIME:19980101T050000Z
REPEAT:23
DURATION:PT1H
ACTION:PROCEDURE
ATTACH:ftp://host.com/novo-procs/felizano.exe
END:VALARM

4.7 Calendar Properties

The Calendar Properties are attributes that apply to the "blind" nature of most exchange
processes using this memo, these access classifications cannot serve iCalendar
object, as an enforcement statement for a system receiving an iCalendar
object. Rather, they provide whole. These properties do not appear within a method for capturing the intention of
the calendar owner for
component. They should be specified after the access "BEGIN:VCALENDAR"
property and prior to the any calendar component. The
[ICMS] provides a broader description of

4.7.1 Calendar Scale

Property Name: CALSCALE

Purpose: This property defines the security system within a calendar application.

No scale used for the
calendar information specified in the iCalendar object.

Value Type: TEXT

Property Parameters: Non-standard property parameters MAY can be
specified on this property.

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Conformance: Property can be specified in an iCalendar object. The
default value is "GREGORIAN".

Description: This memo is based on the Gregorian calendar scale. The
Gregorian calendar scale is assumed if this property is not specified
in the iCalendar object. It is expected that other calendar scales
will be defined in other specifications or by future versions of this
memo.

Format Definition: The property is defined by the following notation:

class

calscale = "CLASS" "CALSCALE" calparam ":" [WSP] classvalue calvalue CRLF

classvalue

calparam = "PUBLIC" / "PRIVATE" / "CONFIDENTIAL" / iana-token
/ x-name
;Default is PUBLIC

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calvalue = "GREGORIAN" / iana-token

Example: The following is an example of this property:

CLASS:PUBLIC

4.8.1.4 Comment

CALSCALE:GREGORIAN

4.7.2 Method

Property Name: COMMENT METHOD

Purpose: This property specifies non-processing information intended
to provide a comment to defines the iCalendar object method associated
with the calendar user. object.

Value Type: TEXT

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This The property may can be specified in an iCalendar object.

Description: The When used in a MIME message entity, the value of this
property MAY MUST be specified multiple times.

Only the "ALTREP" or "LANGUAGE" same as the Content-Type "method" parameter
value. This property parameters MAY can only appear once within the iCalendar
object. If either the "METHOD" property or the Content-Type "method"
parameter is specified, then the other must also be specified
on specified.

No methods are defined by this property. specification. This is the subject of
other specifications, such as the iCalendar Transport-independent
Interoperability Protocol (iTIP) defined by [ITIP].

If this property is not present in the iCalendar object, then a
scheduling transaction MUST NOT be assumed. In such cases, the
iCalendar object is merely being used to transport a snapshot of some
calendar information; without the intention of conveying a scheduling
semantic.

Format Definition: The property is defined by the following notation:

The property MAY be specified in any of the calendar components.
comment

method = "COMMENT" [commparam] "METHOD" metparam ":" [WSP] text metvalue CRLF

commparam

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metparam = [";" [WSP] altrepparm ] [";" [WSP] languageparm] *(";" xparam)

metvalue = iana-token

Example: The following is an example of this property:

COMMENT:The meeting really needs to include both ourselves
and the customer. We can't hold this meeting without them
As a matter of fact\, the venue for the meeting ought to be at
their site. - - John

The data type for following is a hypothetical example of this property to
convey that the iCalendar object is TEXT.

4.8.1.5 Description a request for a meeting:

METHOD:REQUEST

4.7.3 Product Identifier

Property Name: DESCRIPTION PRODID

Purpose: This property provides a more complete description of specifies the
calendar component, than identifier for the product that provided by
created the "SUMMARY" property. iCalendar object.

Value Type: TEXT

Conformance: The property MAY be specified in the "VEVENT", "VTODO"
and "VJOURNAL" calendar components. The

Property Parameters: Non-standard property MAY parameters can be
specified
multiple times only within a "VJOURNAL" calendar component. on this property.

Conformance: The property MAY MUST be specified once in "VALARM" calendar component. an iCalendar
object.

Description: This property is used in the "VEVENT" and "VTODO" to
capture lengthy textual decriptions associated with The vendor of the activity.

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This property implementation should assure that this
is used a globally unique identifier; using some technique such as an FPI
value, as defined in the "VJOURNAL" calendar component to capture
one more textual journal entries. [ISO 9070].

This property is should not be used in the "VALARM" calendar component to capture alter the display text for a DISPLAY category interpretation of alarm, to capture the body
text for an EMAIL category of alarm and to capture the arguement
string for a PROCEDURE category of alarm.

Only
iCalendar object beyond the "ALTREP" or "LANGUAGE" property parameters MAY be semantics specified
on in this property. memo. For
example, it is not to be used to further the understanding of non-
standard properties.

Format Definition: The property is defined by the following notation:

description

prodid = "DESCRIPTION" [descparam] "PRODID" pidparam ":" [WSP] text pidvalue CRLF

descparam

pidparam = [";" [WSP] altrepparm] [";" [WSP] languageparm]

Example: The following *(";" xparam)

pidvalue = text
;Any text that describes the product and version
;and that is an example generally assured of the property with formatted
line breaks in the property value:

DESCRIPTION:Meeting to provide technical review for "Phoenix"
design.\n Happy Face Conference Room. Phoenix design team
MUST attend this meeting.\n RSVP to team leader. being unique.

Example: The following is an example of the property with folding of long
lines:

DESCRIPTION:Last draft of the new novel this property. It does not
imply that English is to be completed
for the editor's proof today.

4.8.1.6 Geographic Position default language.

PRODID:-//ABC Corporation//NONSGML My Product//EN

4.7.4 Version

Property Name: GEO VERSION

Purpose: This property specifies information related to the global
position for the activity specified by a calendar component.

Value Type: Two FLOAT values.

Conformance: This property MAY be specified in an iCalendar object.

Description: The property value specifies latitude and longitude, in
that order (i.e., "LAT LON" ordering). The longitude represents the
location east and west of identifier corresponding to the prime meridian as a positive
highest version number or
negative real number, respectively. The latitude represents the
location north and south of the equator as a positive or negative
real number, respectively. The longitude and latitude values MUST be
specified as decimal degrees minimum and should be specified to six decimal
places. This will allow for granularity within a meter maximum range of the
geographical position. The simple formula for converting degrees-
minutes-seconds into decimal degrees is:

decimal = degrees + minutes/60 + seconds/3600.

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iCalendar specification that is required in order to interpret the
iCalendar object.

Value Type: TEXT

Property Parameters: Non-standard property parameters MAY can be
specified on this property.

Conformance: This property MUST be specified by an iCalendar object,
but MUST only be specified on once.

Description: A value of "2.0" corresponds to this property. memo.

Format Definition: The property is defined by the following notation:

geo

version = "GEO" "VERSION" verparam ":" [WSP] geovalue vervalue CRLF

geovalue

verparam = float *(";" xparam)

vervalue = "2.0" ;This memo
/ maxver
/ (minver ";" [WSP] float
;Latitude and Longitude components maxver)

minver = <A IANA registered iCalendar version identifier>
;Minimum iCalendar version needed to parse the iCalendar object

maxver = <A IANA registered iCalendar version identifier>
;Maximum iCalendar version needed to parse the iCalendar object

Example: The following is an example of this property:

GEO:37.386013;-122.082932

4.8.1.7 Location

VERSION:2.0

4.8 Component Properties

The following properties can appear within calendar components, as
specified by each component property definition.

4.8.1 Descriptive Component Properties

The following properties specify descriptive information about
calendar components.

4.8.1.1 Attachment

Property Name: LOCATION ATTACH

Purpose: The property defines the intended venue for provides the activity
defined by capability to associate a document
object with a calendar component.

Value Type: TEXT

Conformance: This The default value type for this property MAY is URI. The
value type can also be specified reset to BINARY in the "VEVENT" or
"VTODO" calendar component.

Description: Specific venues such as conference or meeting rooms may order to include inline
binary encoded content information.

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Property Parameters: Non-standard, inline encoding, value data type
property parameters can be explicitly specified using on this property. An alternate
representation may

Conformance: The property can be specified that is a URI that points to
directory information with more structured specification of the
location. For example, the alternate representation may specify
either an LDAP URI pointing to in an LDAP server entry or a CID URI
pointing to a MIME body part containing a vCard for the location.

Only the "ALTREP" iCalendar object.

Description: The property can be specified within "VEVENT", "VTODO",
"VJOURNAL", or "LANGUAGE" "VALARM" calendar components. This property parameters MAY can be
specified
on this property. multiple times within an iCalendar object.

Format Definition: The property is defined by the following notation:

location

attach = "LOCATION [locparam] "ATTACH" attparam ":" [WSP] text uri CRLF

locparam

attach =/ "ATTACH" attparam ";" "ENCODING" "=" "BASE64"
";" "VALUE" "=" "BINARY" ":" binary

attparam = [";" [WSP] altrepparm] [";" [WSP] languageparm] *(";" xparam)

Example: The following are some examples of this property:

LOCATION:Conference Room - F123, Bldg. 002

LOCATION;ALTREP="http://xyzcorp.com/conf-rooms/f123.vcf":
Conference Room - F123, Bldg. 002

4.8.1.8 Percent Complete

ATTACH:CID:jsmith.part3.960817T083000.xyzMail@host1.com

ATTACH:FTP://xyzCorp.com/pub/reports/r-960812.ps

4.8.1.2 Categories

Property Name: PERCENT-COMPLETE

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Purpose: This property is used by an assignee or delegatee of a to-do
to convey the percent completion of a to-do to defines the Organizer.

Value Type: INTEGER

Conformance: This property MAY only be specified in categories for a "VTODO" calendar
component.

Description: The property value is a postive integer between zero and
one hundred. A value of "0" indicates the to-do has not yet been
started. A value of "100" indicates that the to-do has been
completed. Integer values in between indicate the percent partially
complete.

When a to-do is assigned to multiple individuals, the property value
indicates the percent complete for that portion of the to-do assigned
to the assignee or delegatee. For example, if a to-do is assigned to
both individuals "A" and "B". A reply from "A" with a percent
complete of "70" indicates that "A" has completed 70% of the to-do
assigned to them. A reply from "B" with a percent complete of "50"
indicates "B" has completed 50% of the to-do assigned to them.

Value Type: TEXT

Property Parameters: Non-standard and language property parameters MAY
can be specified on this property.

Conformance: The property can be specified within "VEVENT", "VTODO"
or "VJOURNAL" calendar components.

Description: This property is used to specify categories or subtypes
of the calendar component. The categories are useful in searching for
a calendar component of a particular type and category. Within the
"VEVENT", "VTODO" or "VJOURNAL" calendar components, more than one
category can be specified as a list of categories separated by the
COMMA character (US-ASCII decimal 44).

Format Definition: The property is defined by the following notation:

percent

categories = "PERCENT-COMPLETE" "CATEGORIES" catparam ":" [WSP] integer text *("," text)
CRLF

catparam = [";" languageparam]
*(";" xparam)

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Example: The following is an example are examples of this property to show 39%
completion:

PERCENT-COMPLETE:39

4.8.1.9 Priority property:

CATEGORIES:APPOINTMENT,EDUCATION

CATEGORIES:MEETING

4.8.1.3 Classification

Property Name: PRIORITY CLASS

Purpose: The This property defines the relative priority access classification for a
calendar component.

Value Type: INTEGER TEXT

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: The property MAY only can be specified once in a "VEVENT" or "VEVENT",
"VTODO" or "VJOURNAL" calendar component. components.

Description: The priority is specified as an integer in the range
zero to nine. A value of zero (ASCII decimal 48) specifies an
undefined priority. A value of one (ASCII decimal 49) is the highest
priority. A value of two (ASCII decimal 50) is the second highest
priority. Subsequent numbers specify a decreasing ordinal priority. A
value of nine (ASCII decimal 58) is the lowest priority.

A CUA with a three-level priority scheme of "HIGH", "MEDIUM" and
"LOW" is mapped into this property such that a property value in the

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range of An access classification is only one (ASCII decimal 49) to four (ASCII decimal 52) specifies
"HIGH" priority. A value component of five (ASCII decimal 53) is the normal or
"MEDIUM" priority. A value in
general security system within a calendar application. It provides a
method of capturing the range scope of six (ASCII decimal 54) to
nine (ASCII decimal 58) the access the calendar owner
intends for information within an individual calendar entry. The
access classification of an individual iCalendar component is "LOW" priority.

A CUA useful
when measured along with the other security components of a priority schema calendar
system (e.g., calendar user authentication, authorization, access
rights, access role, etc.). Hence, the semantics of "A1", "A2", "A3", "B1", "B2", ...,
"C3" is mapped into the individual
access classifications cannot be completely defined by this property such that a property value memo
alone. Additionally, due to the "blind" nature of one
(ASCII decimal 49) specifies "A1", most exchange
processes using this memo, these access classifications cannot serve
as an enforcement statement for a property value of two (ASCII
decimal 50) specifies "A2", system receiving an iCalendar
object. Rather, they provide a property value method for capturing the intention of three (ASCII decimal
51) specifies "A3", and so forth up
the calendar owner for the access to the calendar component. The
[ICMS] provides a property value broader description of 9 (ASCII
decimal 58) specifies "C3".

Other integer values are reserved for future use.

Within the security system within a "VEVENT"
calendar component, application.

Format Definition: The property is defined by the following notation:

class = "CLASS" classparam ":" classvalue CRLF

classparam = *(";" xparam)

classvalue = "PUBLIC" / "PRIVATE" / "CONFIDENTIAL" / iana-token
/ x-name
;Default is PUBLIC

Example: The following is an example of this property:

CLASS:PUBLIC

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4.8.1.4 Comment

Property Name: COMMENT

Purpose: This property specifies non-processing information intended
to provide a
priority for comment to the event. This property may be useful when more than
one event is scheduled for a given time period.

Within a "VTODO" calendar component, this user.

Value Type: TEXT

Property Parameters: Non-standard, alternate text representation and
language property parameters can be specified a
priority for the to-do. on this property.

Conformance: This property is useful can be specified in prioritizing
multiple action items for a given time period.

No an iCalendar object.

Description: The property parameters MAY can be specified on this property. multiple times.

Format Definition: The property is specified defined by the following notation:

priority

comment = "PRIORITY" "COMMENT" commparam ":" [WSP] privalue text CRLF
;Default is zero

privalue

commparam = integer ;Must be in the range [0..9]
; All other values are reserved for future use [";" altrepparam ] [";" languageparam]
*(";" xparam)

Example: The following is an example of this property:

COMMENT:The meeting really needs to include both ourselves
and the customer. We can't hold this meeting without them.
As a matter of fact\, the venue for the meeting ought to be at
their site. - - John

The data type for this property is TEXT.

4.8.1.5 Description

Property Name: DESCRIPTION

Purpose: This property provides a more complete description of the
calendar component, than that provided by the "SUMMARY" property.

Value Type: TEXT

Property Parameters: Non-standard, alternate text representation and
language property with parameters can be specified on this property.

Conformance: The property can be specified in the highest priority:

PRIORITY:1 "VEVENT", "VTODO",
"VJOURNAL" and "VALARM" calendar components. The following is an example of a property with a next highest
priority:

PRIORITY:2

Example: The following is an example of can be
specified multiple times only within a property with no priority. "VJOURNAL" calendar component.

Description: This property is equivalent used in the "VEVENT" and "VTODO" to not specifying
capture lengthy textual decriptions associated with the "PRIORITY" property.:

PRIORITY:0

4.8.1.10 Resources

Property Name: RESOURCES

Purpose: activity.

This property defines is used in the equipment or resources anticipated
for an activity specified by a "VJOURNAL" calendar entity.. component to capture
one more textual journal entries.

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Value Type: TEXT

Conformance:

This property MAY be specified is used in a "VEVENT" or "VTODO" the "VALARM" calendar component.

Description: The property value is an arbitrary text. More than one
resource MAY be specified as component to capture
the display text for a list DISPLAY category of resources separated by alarm, to capture the
COMMA character (ASCII decimal 44).

Only body
text for an EMAIL category of alarm and to capture the "LANGUAGE" property parameter MAY be specified on this
property. arguement
string for a PROCEDURE category of alarm.

Format Definition: The property is defined by the following notation:

resources

description = "RESOURCES" [resrcparam] "DESCRIPTION" descparam ":" [WSP] resvalist text CRLF

resrcparam = ";" [WSP] languageparm

resvalist = resvalue / resvalue "," [WSP] resvalist

resvalue

descparam = "CATERING" / "CHAIRS" / "COMPUTER PROJECTOR"
/ "EASEL" / "OVERHEAD PROJECTOR" / "SPEAKER PHONE"
/ "TABLE" / "TV" / "VCR" / "VIDEO PHONE" / "VEHICLE"
/ text
;These are just examples. [";" altrepparam] [";" languageparam]
*(";" xparam)

Example: The following is an example of this property:

RESOURCES:EASEL,PROJECTOR,VCR

4.8.1.11 Status the property with formatted
line breaks in the property value:

DESCRIPTION:Meeting to provide technical review for "Phoenix"
design.\n Happy Face Conference Room. Phoenix design team
MUST attend this meeting.\n RSVP to team leader.

The following is an example of the property with folding of long
lines:

DESCRIPTION:Last draft of the new novel is to be completed
for the editor's proof today.

4.8.1.6 Geographic Position

Property Name: STATUS GEO

Purpose: This property defines specifies information related to the overall status or confirmation global
position for the activity specified by a calendar component.

Value Type: TEXT FLOAT. The value MUST be two SEMICOLON separated FLOAT
values.

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This property MAY only can be specified in the "VEVENT",
"VTODO", "VJOURNAL" calendar components. an iCalendar object.

Description: In a group scheduled calendar component, the The property is
used by value specifies latitude and longitude, in
that order (i.e., "LAT LON" ordering). The longitude represents the "Organizer" to provide a confirmation
location east and west of the event to the
"Attendees". For example in a "VEVENT" calendar component, the
"Organizer" can indicate that prime meridian as a meeting is tentative, confirmed positive or
cancelled. In a "VTODO" calendar component,
negative real number, respectively. The latitude represents the "Organizer" can
indicate that an action item needs action, is completed, is in
process or being worked on, or has been cancelled. In a "VJOURNAL"
calendar component,
location north and south of the "Organizer" can indicate that equator as a journal entry
is draft, final or has been cancelled positive or removed.

No property parameter MAY negative
real number, respectively. The longitude and latitude values MUST be
specified on this property.

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places. This will allow for granularity within a meter of the
geographical position. The simple formula for converting degrees-
minutes-seconds into decimal degrees is:

decimal = degrees + minutes/60 + seconds/3600.

Format Definition: The property is defined by the following notation:

status

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geo = "STATUS" "GEO" geoparam ":" [WSP] statvalue geovalue CRLF

statvalue

geoparam = "TENTATIVE" ;Indicates event is
;tentative.
/ "CONFIRMED" ;Indicates event is
;definite.
/ "CANCELLED" ;Indicates event was
;cancelled.
;Status values for a "VEVENT"

statvalue =/ "NEEDS-ACTION" ;Indicates to-do needs action.
/ "COMPLETED" ;Indicates to-do completed.
/ "IN-PROCESS" ;Indicates to-do in process of
/ "CANCELLED" ;Indicates to-do was cancelled.
;Status values for "VTODO".

statvalue =/ "DRAFT" ;Indicates journal is draft.
/ "FINAL" ;Indicates journal is final.
/ "CANCELLED" ;Indicates journal is removed.
;Status values for "VJOURNAL". *(";" xparam)

geovalue = float ";" float
;Latitude and Longitude components

Example: The following is an example of this property for a "VEVENT"
calendar component:

STATUS:TENTATIVE

The following is an example of this property for a "VTODO" calendar
component:

STATUS:NEEDS-ACTION

The following is an example of this property for a "VJOURNAL"
calendar component:

STATUS:DRAFT

4.8.1.12 Summary property:

GEO:37.386013;-122.082932

4.8.1.7 Location

Property Name: SUMMARY LOCATION

Purpose: This The property defines a short summary or subject the intended venue for the activity
defined by a calendar component.

Value Type: TEXT

Property Parameters: Non-standard, alternate text representation and
language property parameters can be specified on this property.

Conformance: The This property MUST can be specified in the "VEVENT", "VEVENT" or
"VTODO"
and "VJOURNAL" calendar components. In addition, it MAY appear in the
"VALARM" calendar component.

Description: This property is used in the "VEVENT", "VTODO" and
"VJOURNAL" calendar components to capture a short, one line summary
about the activity Specific venues such as conference or journal entry.

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This property meeting rooms may
be explicitly specified using this property. An alternate
representation may be specified that is used in the "VALARM" calendar component a URI that points to capture
the subject
directory information with more structured specification of the
location. For example, the alternate representation may specify
either an EMAIL category of alarm.

Only LDAP URI pointing to an LDAP server entry or a CID URI
pointing to a MIME body part containing a vCard for the "ALTREP" and "LANGUAGE" property parameters MAY be specified
on this property. location.

Format Definition: The property is defined by the following notation:

summary

location = "SUMMARY" [summparam] "LOCATION locparam ":" [WSP] text CRLF

summparam

locparam = [";" [WSP] altrepparm] altrepparam] [";" [WSP] languageparm] languageparam]
*(";" xparam)

Example: The following is an example are some examples of this property:

SUMMARY:Department Party

4.8.2 Date and Time Component Properties

The following properties specify date and time related information in
calendar components.

4.8.2.1 Date/Time Completed

LOCATION:Conference Room - F123, Bldg. 002

LOCATION;ALTREP="http://xyzcorp.com/conf-rooms/f123.vcf":
Conference Room - F123, Bldg. 002

4.8.1.8 Percent Complete

Property Name: COMPLETED PERCENT-COMPLETE

Purpose: This property defines is used by an assignee or delegatee of a to-do
to convey the date percent completion of a to-do to the Organizer.

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Value Type: INTEGER

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This property can be specified in a "VTODO" calendar
component.

Description: The property value is a positive integer between zero
and time one hundred. A value of "0" indicates the to-do has not yet been
started. A value of "100" indicates that the to-do has been
completed. Integer values in between indicate the percent partially
complete.

Value Type: DATE-TIME

Conformance: The property MAY only be specified in a "VTODO"
component in an iCalendar object.

Description: The date is assigned to
both individuals "A" and time must be in "B". A reply from "A" with a UTC format.

No property parameters MAY be specified on this property. percent
complete of "70" indicates that "A" has completed 70% of the to-do
assigned to them. A reply from "B" with a percent complete of "50"
indicates "B" has completed 50% of the to-do assigned to them.

Format Definition: The property is defined by the following notation:

completed

percent = "COMPLETED" "PERCENT-COMPLETE" pctparam ":" [WSP] date-time integer CRLF

pctparam = *(";" xparam)

Example: The following is an example of this property:

COMPLETED:19960401T235959Z

4.8.2.2 Date/Time End property to show 39%
completion:

PERCENT-COMPLETE:39

4.8.1.9 Priority

Property Name: DTEND PRIORITY

Purpose: This The property specifies defines the date and time that relative priority for a calendar
component ends.
component.

Value Type: The default value type is DATE-TIME. The value type MAY
BE reset to a DATE value type.

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Conformance: This INTEGER

Property Parameters: Non-standard property MAY only parameters can be
specified within the "VEVENT",
"VFREEBUSY", and "VTIMEZONE" calendar components.

Description: Within the "VEVENT" calendar component, on this property
defines the date and time by which the event ends. property.

Conformance: The value MUST property can be
later specified in time than the value of the "DTSTART" property.

Within the "VFREEBUSY" calendar component, this property defines the
end date and time for the free a "VEVENT" or busy time information. "VTODO"
calendar component.

Description: The time
MUST be priority is specified as an integer in the UTC time format. The range
zero to nine. A value of zero (US-ASCII decimal 48) specifies an
undefined priority. A value MUST be later
in time than of one (US-ASCII decimal 49) is the
highest priority. A value of two (US-ASCII decimal 50) is the "DTSTART" property.

Only second
highest priority. Subsequent numbers specify a decreasing ordinal

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priority. A value of nine (US-ASCII decimal 58) is the "VALUE" lowest
priority.

A CUA with a three-level priority scheme of "HIGH", "MEDIUM" and "TZID" property parameters MAY be specified on
"LOW" is mapped into this property. The "TZID" property parameter MAY only be specified
when such that a property value in the
range of one (US-ASCII decimal 49) to four (US-ASCII decimal 52)
specifies "HIGH" priority. A value type is DATE-TIME.

Format Definition: The property of five (US-ASCII decimal 53) is defined by
the following notation:

dtend = "DTEND" [dtendparam]":" [WSP] dtendval CRLF

dtendparam = [";" [WSP] "VALUE" "=" "DATE-TIME"]
[";" [WSP] "TZID" "=" paramtext

dtendparam =/ ";" [WSP] "VALUE" "=" "DATE"

dtendval = date-time / date
;Value MUST match normal or "MEDIUM" priority. A value type

Example: The following in the range of six (US-
ASCII decimal 54) to nine (US-ASCII decimal 58) is an example "LOW" priority.

A CUA with a priority schema of "A1", "A2", "A3", "B1", "B2", ...,
"C3" is mapped into this property:

DTEND:19960401T235959Z

DTEND;VALUE=DATE:19980704

4.8.2.3 Date/Time Due

Property Name: DUE

Purpose: This property defines the date and time such that a to-do is
expected to be completed.

Value Type: The default property value type is DATE-TIME. The of one
(US-ASCII decimal 49) specifies "A1", a property value type MAY
BE reset of two (US-
ASCII decimal 50) specifies "A2", a property value of three (US-ASCII
decimal 51) specifies "A3", and so forth up to a DATE value type.

Conformance: The property MAY only be specified in value of 9
(US-ASCII decimal 58) specifies "C3".

Other integer values are reserved for future use.

Within a "VTODO" "VEVENT" calendar
component and only once.

Description: The value MUST be component, this property specifies a date/time equal to or after the
DTSTART value, if specified.

Only
priority for the "VALUE" and "TZID" event. This property parameters MAY may be specified on useful when more than
one event is scheduled for a given time period.

Within a "VTODO" calendar component, this property. The "TZID" property parameter MAY only be specified
when a
priority for the value type to-do. This property is DATE-TIME.

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multiple action items for a given time period.

Format Definition: The property is defined specified by the following
notation:

due

priority = "DUE" [dueparam]":" [WSP] dueval "PRIORITY" prioparam ":" privalue CRLF

dueparam
;Default is zero

prioparam = [";" [WSP] "VALUE" "=" "DATE-TIME"]
[";" [WSP] "TZID" "=" paramtext

dueparam =/ ";" [WSP] "VALUE" "=" "DATE"

dueval *(";" xparam)

privalue = date-time / date
;Value MUST match value type

Example: The following is an example of this property:

DUE:19960401T235959Z

4.8.2.4 Date/Time Start

Property Name: DTSTART

Purpose: This property specifies when the calendar component begins.

Value Type: The default value type is DATE-TIME. The DATE-TYPE value
will be one of the forms defined for the DATE-TIME value type. The
value type MAY BE reset to a DATE value type.

Conformance: This property MAY integer ;Must be specified within the "VEVENT",
"VTODO", "VFREEBUSY", and "VTIMEZONE" calendar components.

Description: Within the "VEVENT" calendar component, this property
defines in the start date and time range [0..9]
; All other values are reserved for future use

The following is an example of a property with the event. highest priority:

PRIORITY:1

The following is an example of a property with a next highest
priority:

PRIORITY:2

Example: The following is
REQUIRED in "VEVENT" calendar components. Events MAY have an example of a start
date/time but property with no end date/time. In that case, the event does priority.
This is equivalent to not take
up any time.

Within specifying the "VFREEBUSY" calendar component, this "PRIORITY" property.:

PRIORITY:0

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4.8.1.10 Resources

Property Name: RESOURCES

Purpose: This property defines the
start date and time for the free equipment or busy time information. The time
MUST be specified in UTC time.

Within the "VTIMEZONE" calendar component, this property defines the
effective start date and time resources anticipated
for an activity specified by a time zone specification. This
property is REQUIRED within "VTIMEZONE" calendar components. The time
MUST be specified in the UTC time format.

Only the "VALUE" entity..

Value Type: TEXT

Property Parameters: Non-standard, alternate text representation and "TZID"
language property parameters MAY can be specified on this property. The "TZID"

Conformance: This property parameter MAY only can be specified
when the in a "VEVENT" or "VTODO"
calendar component.

Description: The property value type is DATE-TIME. an arbitrary text. More than one
resource can be specified as a list of resources separated by the
COMMA character (US-ASCII decimal 44).

Format Definition: The property is defined by the following notation:

dtstart

resources = "DTSTART" [dtstparam] "RESOURCES" resrcparam ":" [WSP] dtstval CRLF

dtstparam = [";" [WSP] "VALUE" "=" "DATE-TIME"]
[";" [WSP] "TZID" "=" paramtext]

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dtstparam =/ ";" [WSP] "VALUE" "=" "DATE"

dtstval = date-time / date
;Value MUST match value type text *("," text) CRLF

resrcparam = [";" altrepparam] [";" languageparam]
*(";" xparam)

Example: The following is an example of this property:

DTSTART:19980118T073000Z

4.8.2.5 Duration

RESOURCES:EASEL,PROJECTOR,VCR

RESOURCES;LANGUAGE=fr:1 raton-laveur

4.8.1.11 Status

Property Name: DURATION STATUS

Purpose: The This property specifies a duration of time . defines the overall status or confirmation for
the calendar component.

Value Type: DURATION TEXT

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: The This property MAY can be specified in a the "VEVENT", "VTODO",
"VFREEBUSY" or "VALARM" "VTODO"
and "VJOURNAL" calendar components.

Description: In a "VEVENT" group scheduled calendar component component, the property may be is
used by the "Organizer" to specify provide a duration confirmation of the event, instead of an explicit end
date/time. event to the
"Attendees". For example in a "VEVENT" calendar component, the
"Organizer" can indicate that a meeting is tentative, confirmed or
cancelled. In a "VTODO" calendar component component, the "Organizer" can
indicate that an action item needs action, is completed, is in
process or being worked on, or has been cancelled. In a "VJOURNAL"

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calendar component, the "Organizer" can indicate that a journal entry
is draft, final or has been cancelled or removed.

Format Definition: The property may be used
to specify is defined by the following notation:

status = "STATUS" statparam] ":" statvalue CRLF

statparam = *(";" xparam)

statvalue = "TENTATIVE" ;Indicates event is
;tentative.
/ "CONFIRMED" ;Indicates event is
;definite.
/ "CANCELLED" ;Indicates event was
;cancelled.
;Status values for a duration "VEVENT"

statvalue =/ "DRAFT" ;Indicates journal is draft.
/ "FINAL" ;Indicates journal is final.
/ "CANCELLED" ;Indicates journal is removed.
;Status values for the to-do, instead of "VJOURNAL".

Example: The following is an explicit due
date/time. In a "VFREEBUSY" calendar component the property may be
used to specify the interval example of free time being requested. In a
"VALARM" calendar component the property may be used to specify the
delay period prior to repeating an alarm.

No property parameters MAY be specified on this property.

Format Definition: The property is defined by the following notation:

duration = "DURATION" ":" [WSP] duration CRLF

Example: for a "VEVENT"
calendar component:

STATUS:TENTATIVE

The following is an example of this property that specifies
an interval of time of 1 hour and zero minutes and zero seconds:

DURATION:PT1H0M0S for a "VTODO" calendar
component:

STATUS:NEEDS-ACTION

The following is an example of this property that specifies an
interval of time of 15 minutes.

DURATION:PT15M

4.8.2.6 Free/Busy Time for a "VJOURNAL"
calendar component:

STATUS:DRAFT

4.8.1.12 Summary

Property Name: FREEBUSY SUMMARY

Purpose: The This property defines one or more free a short summary or busy time
intervals. subject for the
calendar component.

Value Type: PERIOD. The data TEXT

Property Parameters: Non-standard, alternate text representation and time value MUST
language property parameters can be in a UTC time
format. specified on this property.

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Conformance: The property MAY only be specified in a "VFREEBUSY"
calendar component.

Description: These time periods MAY be specified as either a start
and end date-time or a start date-time and duration. The date and
time MUST be a UTC time format.

The "FREEBUSY" property MAY include the "TYPE" property parameter to
specify whether the information defines a FREE or BUSY time interval.
The default "TYPE" property parameter value is BUSY.

If the "TYPE" property parameter is set to "BUSY", then the

Conformance: The property
MAY also include can be specified in the "BSTAT" "VEVENT", "VTODO",
"VJOURNAL" and "VALARM" calendar components.

Description: This property parameter to provide added
information about the busy time. For example, if the busy time is
associated with a time interval that would be unavailable for
scheduling used in any case the parameter MAY BE set "VEVENT", "VTODO" and
"VJOURNAL" calendar components to UNAVAILABLE or if
the busy time that has been tentatively scheduled capture a short, one line summary
about the parameter MAY
BE set to TENTATIVE. The default "BSTAT" activity or journal entry.

This property parameter value is
BUSY, providing no additional busy status information.

"FREEBUSY" properties within used in the "VFREEBUSY" "VALARM" calendar component
should be sorted in ascending order, based on start time and then end
time, with to capture
the earliest periods first. subject of an EMAIL category of alarm.

Format Definition: The "FREEBUSY" property MAY specify more than one value, separated is defined by the COMMA character (ASCII decimal 44). In such cases, the "FREEBUSY"
property values should all be following notation:

summary = "SUMMARY" summparam ":" text CRLF

summparam = [";" altrepparam] [";" languageparam]
*(";" xparam)

Example: The following is an example of the same "TYPE" this property:

SUMMARY:Department Party

4.8.2 Date and "BSTAT" property
parameter type (e.g., all values of a particular "TYPE" Time Component Properties

The following properties specify date and "BSTAT"
listed together time related information in a single property).

No
calendar components.

4.8.2.1 Date/Time Completed

Property Name: COMPLETED

Purpose: This property parameters other than defines the property specific "TYPE" date and
"BSTAT" time that a to-do was
actually completed.

Value Type: DATE-TIME

Property Parameters: Non-standard property parameters MAY can be
specified on this property.

Conformance: The property can be specified in a "VTODO" calendar
component.

Description: The date and time must be specified on this property. in a UTC format.

Format Definition: The property is defined by the following notation:

freebusy

completed = "FREEBUSY" [";" [WSP] fbparmlist] "COMPLETED" compparam ":" [WSP] fbvalue date-time CRLF

fbparmlist = fb-free / fb-busy

fb-free

compparam = "TYPE" "=" "FREE"

fb-busy = ["TYPE" "=" "BUSY"] [";" [WSP] fbstatus]
;Default *(";" xparam)

Example: The following is BUSY

fbstatus = "BSTAT" "="
"BUSY" ;Represents busy time interval.
/ "UNAVAILABLE" ;Represents busy, but unavailable
;interval for cheduling; such as
;out-of-office or non-working hours.
/ "TENTATIVE" ;Represents busy, but only tentatively
;scheduled interval.
/ iana-token ;Represents other registered busy status an example of this property:

COMPLETED:19960401T235959Z

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/ x-name ;Represents experimental busy status
;Default is BUSY

fbvalue = period *["," [WSP] period]
;Time value MUST be in the UTC time format.

Example: The following are some examples of this property:

FREEBUSY;BSTAT=UNAVAILABLE:19970308T160000Z/PT8H30M

FREEBUSY;TYPE=FREE:19970308T160000Z/PT3H,19970308T200000Z/PT1H

4.8.2.7 Time Transparency

4.8.2.2 Date/Time End

Property Name: TRANSP DTEND

Purpose: This property defines whether an event is transparent or not
to busy specifies the date and time searches. that a calendar
component ends.

Value Type: TEXT The default value type is DATE-TIME. The value type can
be reset to a DATE value type.

Property Parameters: Non-standard, value data type, time zone
identifier property parameters can be specified on this property.

Conformance: This property MAY only can be specified in a within the "VEVENT" and
"VFREEBUSY" calendar component. components.

Description: Transparency is Within the state that determines whether an
event takes up time on a calendar, "VEVENT" calendar component, this property
defines the date and with time by which the event ends. The value MUST be reflected as "busy
time", or is just "penciled in" to
later in time than the calendar, value of the "DTSTART" property.

Within the "VFREEBUSY" calendar component, this property defines the
end date and will not be
reflected as "busy time". If time for the event is transparent, then other
events can free or busy time information. The time
MUST be scheduled specified as in the same UTC time period without there being a format. The value MUST be later
in time period conflict. If not specified, than the default state is OPAQUE.

No property parameters MAY be specified on this value of the "DTSTART" property.

Format Definition: The property is specified defined by the following notation:

transp

dtend = "TRANSP" ":" [WSP] transvalue "DTEND" dtendparam":" dtendval CRLF

transvalue

dtendparam = "OPAQUE" ;Blocks or opaque on busy time searches. [";" "VALUE" "=" ("DATE-TIME" / "TRANSPARENT" ;Transparent on busy time searches.
;Default "DATE")]
[";" tzidparam]
*(";" xparam)

dtendval = date-time / date
;Value MUST match value is OPAQUE type

Example: The following is an example of this property:

DTEND:19960401T235959Z

DTEND;VALUE=DATE:19980704

4.8.2.3 Date/Time Due

Property Name: DUE

Purpose: This property for an event defines the date and time that a to-do is transparent or does not block on free/busy time searches:

TRANSP:TRANSPARENT
expected to be completed.

Value Type: The following default value type is an example of this DATE-TIME. The value type can
be reset to a DATE value type.

Property Parameters: Non-standard, value data type, time zone
identifier property for an event that is
opaque or blocks parameters can be specified on free/busy time searches:

TRANSP:OPAQUE this property.

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4.8.3 Time Zone Component Properties

Conformance: The following properties specify time zone information in property can be specified once within a "VTODO"
calendar
components.

4.8.3.1 Time Zone Identifier component.

Description: The value MUST be a date/time equal to or after the
DTSTART value, if specified.

Format Definition: The property is defined by the following notation:

due = "DUE" dueparam":" dueval CRLF

dueparam = [";" "VALUE" "=" ("DATE-TIME" / "DATE")]
[";" tzidparam]
*(";" xparam)

dueval = date-time / date
;Value MUST match value type

Example: The following is an example of this property:

DUE:19980430T235959Z

4.8.2.4 Date/Time Start

Property Name: TZID DTSTART

Purpose: This property specifies when the text value that uniquely
identifies the VTIMZONE calendar component. component begins.

Value Type: TEXT The default value type is DATE-TIME. The time value MUST
be one of the forms defined for the DATE-TIME value type. The value
type can be reset to a DATE value type.

Property Parameters: Non-standard, value data type, time zone
identifier property parameters can be specified on this property.

Conformance: This property MUST can be specified in a within the "VEVENT",
"VTODO", "VFREEBUSY", and "VTIMEZONE" calendar component. components.

Description: This is Within the key by which a "VEVENT" calendar component, this property
defines the start date and time zone object for the event. The property is
referenced by
REQUIRED in "VEVENT" calendar components. Events can have a start
date/time but no end date/time. In that case, the event does not take
up any iCalendar properties whose data type is either
DATE-TIME time.

Within the "VFREEBUSY" calendar component, this property defines the
start date and time for the free or TIME. busy time information. The presence of time
MUST be specified in UTC time.

Within the SOLIDUS character (ASCII
decimal 47) as a prefix, indicates that "VTIMEZONE" calendar component, this TZID represents an
unique ID in property defines the
effective start date and time for a globally defined time zone registry (when such
registry is defined).

No specification. This
property parameters MAY is REQUIRED within each STANDARD and DAYLIGHT part included
in "VTIMEZONE" calendar components and MUST be specified on this property. as a local
DATE-TIME without the "TZID" property parameter.

Format Definition: This The property is defined by the following notation:

tzid

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dtstart = "TZID" "DTSTART" dtstparam ":" [WSP] [tzidprefix] text dtstval CRLF

tzidprefix

dtstparam = "/" [";" "VALUE" "=" ("DATE-TIME" / "DATE")]
[";" tzidparam]
*(";" xparam)

dtstval = date-time / date
;Value MUST match value type

Example: The following are examples of non-globally unique time zone
identifiers:

TZID:America-New_York

TZID:/US-California-Los_Angeles

The following is an example of a globally unique time zone
identifier:

TZID:/US-New York-New_York

4.8.3.2 Time Zone Name this property:

DTSTART:19980118T073000Z

4.8.2.5 Duration

Property Name: TZNAME DURATION

Purpose: This The property specifies the customary designation for a positive duration of time
zone description. .

Value Type: TEXT

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Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This The property MAY only can be specified in the "VTIMEZONE" a "VEVENT", "VTODO",
"VFREEBUSY" and "VALARM" calendar component. components.

Description: This In a "VEVENT" calendar component the property may be specified in multiple languages; in
order
used to provide specify a duration of the event, instead of an explicit end
date/time. In a "VTODO" calendar component the property may be used
to specify a duration for different national language requirements.

Only the "LANGUAGE" to-do, instead of an explicit due
date/time. In a "VFREEBUSY" calendar component the property parameter MAY may be specified on this
property.
used to specify the interval of free time being requested. In a
"VALARM" calendar component the property may be used to specify the
delay period prior to repeating an alarm.

Format Definition: This The property is defined by the following notation:

tzname

duration = "TZNAME" [tznparam] "DURATION" durparam ":" [WSP] text duration CRLF

tznparam
;consisting of a positive duration of time.

durparam = ";" [WSP] languageparm *(";" xparam)

Example: The following are examples is an example of this property that specifies
an interval of time of 1 hour and zero minutes and zero seconds:

DURATION:PT1H0M0S

The following is an example of this property that specifies an
interval of this property:

TZNAME: EST

TZNAME;LANGUAGE=fr-CA:HNE

4.8.3.3 time of 15 minutes.

DURATION:PT15M

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4.8.2.6 Free/Busy Time Zone Offset From

Property Name: TZOFFSETFROM FREEBUSY

Purpose: This The property specifies the offset which is in use prior to
this defines one or more free or busy time zone observance.
intervals.

Value Type: UTC-OFFSET PERIOD. The date and time values MUST be in an UTC time
format.

Property Parameters: Non-standard or free/busy time type property
parameters can be specified on this property.

Conformance: This The property MUST only can be specified in a "VTIMEZONE" "VFREEBUSY" calendar
component. A "VTIMEZONE" calendar component MUST include

Property Parameter: "FBTYPE" and non-standard parameters can be
specified on this property.

Description: This property specifies the offset which is in use prior
to this time observance. It is used to calculate the absolute These time at
which the transition to periods can be specified as either a given observance takes place. This property start
and end date-time or a start date-time and duration. The date and
time MUST only be specified in a "VTIMEZONE" calendar component. A
"VTIMEZONE" UTC time format.

"FREEBUSY" properties within the "VFREEBUSY" calendar component MUST include this property.
should be sorted in ascending order, based on start time and then end
time, with the earliest periods first.

The "FREEBUSY" property value is a signed numeric indicating can specify more than one value, separated by
the number of hours and
possibly minutes from UTC. Positive numbers represents time zones
east, or ahead of UTC. Negative numbers represents time zones west
of, or behind UTC.

No COMMA character (US-ASCII decimal 44). In such cases, the
"FREEBUSY" property parameter MAY values should all be specified on this property. of the same "FBTYPE"
property parameter type (e.g., all values of a particular "FBTYPE"
listed together in a single property).

Format Definition: The property is defined by the following notation:

tzoffsetfrom

freebusy = "TZOFFSETFROM" "FREEBUSY" fbparam ":" [WSP] utc-offset fbvalue
CRLF

fbparam = [";" fbtypeparam] *(";" xparam)

fbvalue = period *["," period]
;Time value MUST be in the UTC time format.

Example: The following are some examples of this property:

TZOFFSETFROM:-0500

FREEBUSY;FBTYPE=BUSY-UNAVAILABLE:19970308T160000Z/PT8H30M

FREEBUSY;FBTYPE=FREE:19970308T160000Z/PT3H,19970308T200000Z/PT1H

FREEBUSY;FBTYPE=FREE:19970308T160000Z/PT3H,19970308T200000Z/PT1H,
19970308T230000Z/19970309T000000Z

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TZOFFSETFROM:+0530

4.8.3.4

4.8.2.7 Time Zone Offset To Transparency

Property Name: TZOFFSETTO TRANSP

Purpose: This property specifies the offset which defines whether an event is in use in this transparent or not
to busy time zone observance. searches.

Value Type: UTC-OFFSET TEXT

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This property MAY only can be specified in once within a "VTIMEZONE" "VEVENT"
calendar component. A "VTIMEZONE" calendar component MUST include
this property.

Description: This property specifies the offset which Transparency is in use in
this the state that determines whether an
event takes up time zone observance. It on a calendar, and with be reflected as "busy
time", or is used just "penciled in" to calculate the absolute calendar, and will not be
reflected as "busy time". If the event is transparent, then other
events can be scheduled in the same time
for period without there being a
time period conflict. If not specified, the new observance. default state is OPAQUE.

Format Definition: The property value is a signed numeric
indicating specified by the number of hours and possibly minutes from UTC.
Positive numbers represents time zones east, following
notation:

transp = "TRANSP" tranparam ":" transvalue CRLF

tranparam = *(";" xparam)

transvalue = "OPAQUE" ;Blocks or ahead of UTC.
Negative numbers represents opaque on busy time zones west of, or behind UTC.

No property parameter MAY be specified searches.
/ "TRANSPARENT" ;Transparent on this property.

Format Definition: busy time searches.
;Default value is OPAQUE

Example: The following is an example of this property for an event
that is defined by the following notation:

tzoffsetto = "TZOFFSETTO" ":" [WSP] utc-offset CRLF

Example: transparent or does not block on free/busy time searches:

TRANSP:TRANSPARENT

The following are examples is an example of this property:

TZOFFSETTO:-0500

TZOFFSETTO:+0530

4.8.3.5 property for an event that is
opaque or blocks on free/busy time searches:

TRANSP:OPAQUE

4.8.3 Time Zone URL Component Properties

The following properties specify time zone information in calendar
components.

4.8.3.1 Time Zone Identifier

Property Name: TZURL TZID

Purpose: The TZURL provides a means for a VTIMEZONE component to
point to a network location This property specifies the text value that can be used to retrieve an up-to-
date version of itself. uniquely
identifies the "VTIMEZONE" calendar component.

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Value Type: URI TEXT

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This property MAY only MUST be specified in a "VTIMEZONE"
calendar component.

Description: The TZURL provides a means for This is the label by which a VTIMEZONE time zone calendar
component is referenced by any iCalendar properties whose data type
is either DATE-TIME or TIME and not intended to
point to a network location that can be used to retrieve an up-to-
date version of itself. This provides specify a hook to handle changes
government bodies impose upon timezone definitions. Retrieval UTC or
a"floating" time. The presence of
this resource results in an iCalendar object containing a single
VTIMEZONE component and the SOLIDUS character (US-ASCII
decimal 47) as a METHOD property set to PUBLISH.

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No property parameter MAY be specified on prefix, indicates that this property. TZID represents an
unique ID in a globally defined time zone registry (when such
registry is defined).

Format Definition: The This property is defined by the following
notation:

tzurl

tzid = "TZURL" "TZID" tzidpropparam ":" [WSP] uri [tzidprefix] text CRLF

tzidpropparam = *(";" xparam)

;tzidprefix = "/"
; Defined previously. Just listed here for reader convenience.

Example: The following are examples of non-globally unique time zone
identifiers:

TZID:America-New_York

TZID:California-Los_Angeles

The following is an example of this property:

TZURL:http://timezones.r.us.net/tz/US-California-Los_Angeles

4.8.4 Relationship Component Properties

The following properties specify relationship information in calendar
components.

4.8.4.1 Attendee a globally unique time zone
identifier:

TZID:/US-New_York-New_York

4.8.3.2 Time Zone Name

Property Name: ATTENDEE TZNAME

Purpose: The This property defines an attendee within specifies the customary designation for a calendar
component. time
zone description.

Value Type: CAL-ADDRESS

Conformance: This TEXT

Property Parameters: Non-standard and language property MUST parameters
can be specified in an iCalendar object
that specifies a group scheduled calendar entity. on this property.

Conformance: This property MUST can be specified in an iCalendar object that specifies the publication of
a "VTIMEZONE"
calendar user's busy time. component.

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Description: This property is not may be specified in an
iCalendar object that specifies only a time zone definition or that
defines calendar entities that are not group scheduled entities, but
are entities only on a single user's calendar.

Description: The property is specified within the "VEVENT", "VTODO",
"VJOURNAL calendar components multiple languages; in
order to specify participants, non-
participants and the chair of a group scheduled calendar entity. The provide for different language requirements.

Format Definition: This property is specified within the "VFREEBUSY" calendar component to
specify the calendar user associated with defined by the free or busy time. following
notation:

tzname = "TZNAME" tznparam ":" text CRLF

tznparam = [";" languageparm]
*(";" xparam)

Example: The following are example of this property:

TZNAME:EST

The
property following is specified within an "EMAIL" category of the "VALARM"
calendar component to specify an email address that is to receive the
email type example of iCalendar alarm.

The property has the this property parameter CN, when two different
languages for the common or
displayable time zone name associated with the calendar address, ROLE, for the
intended role that are specified:

TZNAME;LANGUAGE=en:EST
TZNAME;LANGUAGE=fr-CA:HNE

4.8.3.3 Time Zone Offset From

Property Name: TZOFFSETFROM

Purpose: This property specifies the attendee will have offset which is in the use prior to
this time zone observance.

Value Type: UTC-OFFSET

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This property MUST be specified in a "VTIMEZONE"
calendar component;
ATTSTAT, for the status of the attendee's participation; RSVP, for
indicating whether component.

Description: This property specifies the favor of a reply offset which is requested; EXPECT, in use prior
to
indicate the expectation of the attendee's participation by the
originator; MEMBER, this time observance. It is used to indicate calculate the groups that absolute time at
which the attendee belongs
to; DELEGATED-TO, transition to indicate the a given observance takes place. This property
MUST only be specified in a "VTIMEZONE" calendar users that the original
request was delegated to; and DELEGATED-FROM, to indicate whom the
request was delegated from; SENT-BY, to indicate whom component. A
"VTIMEZONE" calendar component MUST include this property. The
property value is acting on
behalf of a signed numeric indicating the ATTENDEE number of hours and DIR, to indicate the URI that points to
possibly minutes from UTC. Positive numbers represents time zones
east of the directory information corresponding to prime meridian, or ahead of UTC. Negative numbers
represents time zones west of the attendee. These
property parameters MAY only be specified on an "ATTENDEE" prime meridian, or behind UTC.

Format Definition: The property is defined by the following notation:

tzoffsetfrom = "TZOFFSETFROM" frmparam ":" utc-offset
CRLF

frmparam = *(";" xparam)

Example: The following are examples of this property:

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TZOFFSETFROM:-0500

TZOFFSETFROM:+1345

4.8.3.4 Time Zone Offset To

Property Name: TZOFFSETTO

Purpose: This property specifies the offset which is in either a "VEVENT", "VTODO" or "VJOURNAL" calendar component. They
MUST not use in this
time zone observance.

Value Type: UTC-OFFSET

Property Parameters: Non-standard property parameters can be
specified in an "ATTENDEE" on this property.

Conformance: This property MUST be specified in a "VFREEBUSY" or
"VALARM" "VTIMEZONE"
calendar component.

A recipient delegated

Description: This property specifies the offset which is in use in
this time zone observance. It is used to calculate the absolute time
for the new observance. The property value is a request MUST inherit signed numeric
indicating the RSVP number of hours and EXPECT
values possibly minutes from UTC.
Positive numbers represents time zones east of the attendee that delegated prime meridian, or
ahead of UTC. Negative numbers represents time zones west of the request to them.

Multiple attendees MAY be specified
prime meridian, or behind UTC.

Format Definition: The property is defined by including multiple "ATTENDEE"
properties within the MIME calendaring entity.

Only the "TYPE", "CN", "ROLE", "ATTSTAT", "RSVP", "DELEGATED-TO",
"DELEGATED-FROM", "SENT-BY" or "DIR" following notation:

tzoffsetto = "TZOFFSETTO" toparam ":" utc-offset CRLF

toparam = *(";" xparam)

Example: The following are examples of this property:

TZOFFSETTO:-0400

TZOFFSETTO:+1245

4.8.3.5 Time Zone URL

Property Name: TZURL

Purpose: The TZURL provides a means for a VTIMEZONE component to
point to a network location that can be used to retrieve an up-to-
date version of itself.

Value Type: URI

Property Parameters: Non-standard property specific parameters MAY can be
specified on this property. In addition, the "LANGUAGE"

Conformance: This property
parameter MAY can be specified on in a "VTIMEZONE" calendar
component.

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Description: The TZURL provides a means for a VTIMEZONE component to
point to a network location that can be used to retrieve an up-to-
date version of itself. This provides a hook to handle changes
government bodies impose upon time zone definitions. Retrieval of
this property. resource results in an iCalendar object containing a single
VTIMEZONE component and a METHOD property set to PUBLISH.

Format Definition: The property is defined by the following notation:

attendee

tzurl = "ATTENDEE" *(";" [WSP] attparam) "TZURL" tzurlparam ":" [WSP]
cal-address uri CRLF

attparam = typeparm / cnparm / roleparm / statusparm / rsvpparm
/ memberparm / deletoparm / delefromparm
/ sentbyparm / dirparm

typeparm

tzurlparam = "TYPE" "="
("INDIVIDUAL" ; An individual
/ "GROUP" ; A group of individuals
/ "RESOURCE" ; A physical resource
/ "ROOM" ; A room resource
/ "UNKNOWN") ; Otherwise not known
;Default value *(";" xparam)

Example: The following is INDIVIDUAL

cnparm = "CN" "=" param-value

roleparm = "ROLE" "="
("CHAIR" ; Indicates CHAIR an example of the calendar entity
/ "REQ-PARTICIPANT" ; Indicates a participant whose
;participation is required
/ "OPT-PARTICIPANT" ;Indicates a participant whose
;participation is optional
/ "NON-PARTICIPANT" ;Indicates a participant who
;is copied for this property:

TZURL:http://timezones.r.us.net/tz/US-California-Los_Angeles

4.8.4 Relationship Component Properties

The following properties specify relationship information purposes only
;Default is REQ-PARTICIPANT

statusparm = "ATTSTAT" "="
("NEEDS-ACTION" ; Indicates event or to-do needs action
/ "ACCEPTED" ; Indicates event or to-do accepted
/ "DECLINED" ; Indicates event in calendar
components.

4.8.4.1 Attendee

Property Name: ATTENDEE

Purpose: The property defines an "Attendee" within a calendar
component.

Value Type: CAL-ADDRESS

Property Parameters: Non-standard, language, calendar user type,
group or to-do not accepted
/ "TENTATIVE" ; Indicates event list membership, participation role, participation status,
RSVP expectation, delegatee, delegator, sent by, common name or to-do tentatively
; accepted. Status MAY change
directory entry reference property parameters can be specified on
this property.

Conformance: This property MUST be specified in the future.
/ "COMPLETED" ; Indicates to-do was completed.
; COMPLETED an iCalendar object
that specifies a group scheduled calendar entity. This property has date/time completed.
/ "IN-PROCESS" ;Indicates to-do is MUST
NOT be specified in an iCalendar object when publishing the process calendar
information (e.g., NOT in an iCalendar object that specifies the
publication of
; being completed.

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/ "DELEGATED" ; Indicates event or a calendar user's busy time, event, to-do delegated
; to another ATTENDEE
;Default is NEEDS-ACTION

rsvpparm = "RSVP" "="
("TRUE" ; Indicates response requested
/ "FALSE") ; Indicates no response needed
;Default or journal).
This property is FALSE

memberparm = "MEMBER" "=" DQUOTE uri DQUOTE
*("," [WSP] DQUOTE uri DQUOTE)
; Indicates not specified in an iCalendar object that specifies
only a group time zone definition or mailing list
; that defines calendar entities that
are not group scheduled entities, but are entities only on a single
user's calendar.

Description: The property is MUST only be specified within calendar
components to specify participants, non-participants and the chair of
a MAILTO URI as defined in [RFC 1738]
; group scheduled calendar entity. The property is specified within
an "EMAIL" category of the "VALARM" calendar component to specify an
email address that is to receive the email type of iCalendar alarm.

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The property parameter value must be put CN, is for the common or displayable name
associated with the calendar address; ROLE, for the intended role
that the attendee will have in the calendar component; PARTSTAT, for
the status of the attendee's participation; RSVP, for indicating
whether the favor of a quoted string.

deletoparm = "DELEGATED-TO" "=" DQUOTE uri DQUOTE
*("," [WSP] DQUOTE uri DQUOTE)
; Indicates who reply is requested; CUTYPE, to indicate the
type of calendar user; MEMBER, to indicate the groups that the
attendee belongs to; DELEGATED-TO, to indicate the calendar users
that the original request is was delegated to; and DELEGATED-FROM, to
; MUST be a MAILTO
indicate whom the request was delegated from; SENT-BY, to indicate
whom is acting on behalf of the ATTENDEE; and DIR, to indicate the
URI as defined in [RFC 1738]
; The parameter value must that points to the directory information corresponding to the
attendee. These property parameters can be put specified on an "ATTENDEE"
property in either a quoted string.delefromparm =
"DELEGATED-FROM" "=" DQUOTE uri DQUOTE
*("," [WSP]DQUOTE uri DQUOTE)
;Indicates who the request is delegated from
; "VEVENT", "VTODO" or "VJOURNAL" calendar
component. They MUST not be a MAILTO URI as defined specified in [RFC 1738]
; The parameter value must be put an "ATTENDEE" property in a quoted string.

sentbyparm = "SENT-BY" "=" DQUOTE uri DQUOTE
; Indicates a
"VFREEBUSY" or "VALARM" calendar user acting on behalf of component. If the LANGUAGE property
parameter is specified, the identified language applies to the CN
parameter.

A recipient delegated a request MUST inherit the RSVP and ROLE values
from the attendee.
; MUST attendee that delegated the request to them.

Multiple attendees can be a MAILTO URI as defined in [RFC 1738]
; specified by including multiple "ATTENDEE"
properties within the calendar component.

Format Definition: The parameter value must be put in a quoted string.dirparm property is defined by the following notation:

attendee = "DIR" "=" DQUOTE uri DQUOTE "ATTENDEE" attparam ":" cal-address CRLF

attparam = [";" cutypeparam] [";"memberparam] [";" roleparam]
[";" partstatparam] [";" rsvpparam] [";" deltoparam]
[";" delfromparam] [";" sentbyparam] [";"cnparam]
[";" dirparam] [";" languageparam] *(";" xparam)

Example: The following are examples of this property's use for a to-
do:

ORGANIZER:MAILTO:jsmith@host1.com
ATTENDEE;MEMBER="MAILTO:DEV-GROUP@host2.com":
MAILTO:joecool@host2.com
ATTENDEE;DELEGATED-FROM="MAILTO:immud@host3.com":
MAILTO:ildoit@host1.com

The following is an example of this property used for specifying
multiple attendees to an event:

ORGANIZER:MAILTO:jsmith@host1.com
ATTENDEE;ROLE=REQ-PARTICIPANT;ATTSTAT=TENTATIVE;CN=Henry
ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=TENTATIVE;CN=Henry Cabot
:MAILTO:hcabot@host2.com
ATTENDEE;ROLE=REQ-PARTICIPANT;DELEGATED-FROM="MAILTO:bob@host.com"
;ATTSTAT=ACCEPTED;CN=Jane Doe: MAILTO:jdoe@host1.com
;PARTSTAT=ACCEPTED;CN=Jane Doe:MAILTO:jdoe@host1.com

The following is an example of this property with a URI to the
directory information associated with the attendee:

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ATTENDEE;CN=John Smith;DIR="ldap://host.com:6666/o=eDABC%
20Industries,c=3DUS??(cn=3DBJim%20Dolittle)":MAILTO:jimdo@
host1.com

The following is an example of this property with "delegatee" and
"delegator" information for an event:

ORGANIZER;CN=John Smith:MAILTO:jsmith@host.com
ATTENDEE;ROLE=REQ-PARTICIPANT;ATTSTAT=TENTATIVE;DELEGATED-FROM=
ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=TENTATIVE;DELEGATED-FROM=
"MAILTO:iamboss@host2.com";CN=Henry Cabot:MAILTO:hcabot@
host2.com
ATTENDEE;ROLE=NON-PARTICIPANT;ATTSTAT=DELEGATED;DELEGATED-TO=
ATTENDEE;ROLE=NON-PARTICIPANT;PARTSTAT=DELEGATED;DELEGATED-TO=
"MAILTO:hcabot@host2.com";CN=The Big Cheese:MAILTO:iamboss
@host2.com
ATTENDEE;ROLE=REQ-PARTICIPANT;ATTSTAT=ACCEPTED;CN=Jane
ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=ACCEPTED;CN=Jane Doe
:MAILTO:jdoe@host1.com

Example: The following is an example of this property's use when
another calendar user is acting on behalf of the "Attendee":

ATTENDEE;SENT-BY=MAILTO:jan_doe@host1.com;CN=John Smith:MAILTO:
jsmith@host1.com

4.8.4.2 Contact

Property Name: CONTACT

Purpose: The property is used to represent contact information or
alternately a reference to contact information associated with the
calendar component.

Value Type: TEXT

Property Parameters: Non-standard, alternate text representation and
language property parameters can be specified on this property.

Conformance: The property MAY only can be specified in a "VEVENT",
"VTODO" and "VTODO",
"VJOURNAL" and "VFREEBUSY" calendar component in an iCalendar object. component.

Description: The property value consists of textual contact
information. An alternative representation for the property value MAY can
also be specified that refers to a URI pointing to an alternate form,
such as a vCard, for the contact information.

Only the "ALTREP" or "LANGUAGE" property parameters MAY be specified
on this property.

Format Definition: The property is defined by the following notation:

contact = "CONTACT" [contparam] contparam ":" [WSP] text CRLF

contparam = [";" [WSP] altrepparm] altrepparam] [";" [WSP] languageparm] languageparam]
*(";" xparam)

Example: The following is an example of this property referencing
textual contact information:

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CONTACT:Jim Dolittle\, ABC Industries\, +1-919-555-1234

The following is an example of this property with an alternate
representation of a LDAP URI to a directory entry containing the
contact information:

CONTACT;ALTREP="ldap://host.com:6666/o=3DABC%20Industries\,
c=3DUS??(cn=3DBJim%20Dolittle)":Jim Dolittle\, ABC Industries\,
+1-919-555-1234

The following is an example of this property with an alternate
representation of a MIME body part containing the contact
information, such as a vCard embedded in a [MIME-DIR] content-type:

CONTACT;ALTREP="CID=<part3.msg970930T083000SILVER@host.com>":Jim
Dolittle\, ABC Industries\, +1-919-555-1234

The following is an example of this property referencing a network
resource, such as a vCard object containing the contact information:

CONTACT;ALTREP="http://host.com/pdi/jdoe.vcf":Jim
Dolittle\, ABC Industries\, +1-919-555-1234

4.8.4.3 Organizer

Property Name: ORGANIZER

Purpose: The property defines the organizer for a calendar component.

Value Type: CAL-ADDRESS

Property Parameters: Non-standard, language, common name, directory
entry reference, sent by property parameters can be specified on this
property.

Conformance: This property MUST be specified in an iCalendar object
that specifies a group scheduled calendar entity. This property MUST
be specified in an iCalendar object that specifies the publication of
a calendar user's busy time. This property MUST not NOT be specified in
an iCalendar object that specifies only a time zone definition or
that defines calendar entities that are not group scheduled entities,
but are entities only on a single user's calendar.

Description: The property is specified within the "VEVENT", "VTODO",
"VJOURNAL calendar components to specify the organizer of a group
scheduled calendar entity. The property is specified within the
"VFREEBUSY" calendar component to specify the calendar user
requesting the free or busy time. When publishing a "VFREEBUSY"
calendar component, the property is used to specify the calendar that
the published busy time came from.

The property has the property parameters CN, for specifying the
common or display name associated with the "Organizer", DIR, for
specifying a pointer to the directory information associated with the

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"Organizer", SENT-BY, for specifying another calendar user that is
acting on behalf of the "Organizer". No other The non-standard parameters MAY may
also be specified on this property. If the LANGUAGE property
parameter is specified, the identified language applies to the CN
parameter value.

Format Definition: The property is defined by the following notation:

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organizer = "ORGANIZER" [orgparam] orgparam ":" [WSP]
cal-address CRLF

orgparam = [";" [WSP] "CN" "=" param-value] cnparam] [";" [WSP] "DIR" "=" DQUOTE uri DQUOTE]
proxyparam

proxyparam = (";" [WSP] "SENT-BY" "=" DQUOTE cal-address DQUOTE) dirparam] [";" sentbyparam]
[";" languageparam] *(";" xparam)

Example: The following is an example of this property:

ORGANIZER;CN=John Smith:MAILTO:jsmith@host1.com

The following is an example of this property with a pointer to the
directory information associated with the organizer:

ORGANIZER;CN=JohnSmith;DIR="ldap://host.com:6666/o=3DDC%20Associ
ates,c=3DUS??(cn=3DJohn%20Smith)":MAILTO:jsmith@host1.com

The following is an example of this property used by another calendar
user who is acting on behalf of the organizer, with responses
intended to be sent back to the organizer, not the other calendar
user:

ORGANIZER;SENT-BY="MAILTO:jane_doe@host.com":
MAILTO:jsmith@host1.com

4.8.4.4 Recurrence ID

Property Name: RECURRENCE-ID

Purpose: This property is used in conjunction with the "UID" and
"SEQUENCE" property to identify a specific instance of a recurring
"VEVENT", "VTODO" or "VJOURNAL" calendar component. The property
value is the effective value of the "DTSTART" property of the
recurrence instance.

Value Type: The default value type for this property is DATE-TIME.
The time format MAY BE can be any of the valid forms defined for a DATE-TIME
value type. See DATE-TIME value type definition for specific
interpretations of the various forms. The value type MAY can be reset to
DATE.

Property Parameters: Non-standard property, value data type, time
zone identifier and recurrence identifier range parameters can be reset to
DATE.
specified on this property.

Conformance: This property MAY can be specified in an iCalendar object
containing a recurring calendar component.

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Description: The full range of calendar components specified by a
recurrence set is referenced by referring to just the "UID" property
value corresponding to the calendar component. The "RECURRENCE-ID"
property allows the reference to an individual instance within the
recurrence set.

If the value of the "DTSTART" property is a DATE type value, then the
value MUST be the calendar date for the recurrence instance.

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The date/time value is set to the time when the original recurrence
instance would occur - - meaning that if the intent is to change a
Friday meeting to Thursday, the date/time is still set to the
original Friday meeting.

The "RECURRENCE-ID" property is used in conjunction with the "UID"
and "SEQUENCE" property to identify a particular instance of a
recurring event, to-do or journal. For a given pair of "UID" and
"SEQUENCE" property values, the "RECURRENCE-ID" value for a
recurrence instance is fixed. When the definition of the recurrence
set for a calendar component changes, and hence the "SEQUENCE"
property value changes, the "RECURRENCE-ID" for a given recurrence
instance might also change.The "RANGE" parameter is used to specify
the effective range of recurrence instances from the instance
specified by the "RECURRENCE-ID" property value. The default value
for the range parameter is the single recurrence instance only. The
value can also be "THISANDPRIOR" to indicate a range defined by the
given recurrence instance and all prior instances or the value can be
"THISANDFUTURE" to indicate a range defined by the given recurrence
instance and all subsequent instances.

Only the "VALUE" property parameter and the property-specific "RANGE"
parameter MAY be specified on this property.

Format Definition: The property is defined by the following notation:

recurid = "RECURRENCE-ID" *(";" [WSP] parameter)
[";" [WSP] rangeparm] ":" [WSP] [date-time / date]
;Value must match value type.

recurid = "RECURRENCE-ID" [ridparam] [rangeparm] ridparam ":" [WSP] ridval CRLF

ridparam = ";" [WSP] [";" "VALUE" "=" ("DATE-TIME" / "DATE" /
/ "PERIOD")

rangeparm = ";" [WSP] "RANGE" "=" ("THISANDPRIOR"
/ "THISANDFUTURE") "DATE)]
[";" tzidparam] [";" rangeparam]
*(";" xparam)

ridval = date-time / date / period
;Value MUST match value type

Example: The following are examples of this property:

RECURRENCE-ID;VALUE=DATE:19960401

RECURRENCE-ID;RANGE=THISANDFUTURE:19960120T120000Z

4.8.4.5 Related To

Property Name: RELATED-TO

Purpose: The property is used to represent a relationship or
reference between one calendar component and another.

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Value Type: TEXT

Property Parameters: Non-standard and relationship type property
parameters can be specified on this property.

Conformance: The property MAY only can be specified once in the "VEVENT",
"VTODO" and "VJOURNAL" calendar components.

Description: The property value consists of the persistent, globally
unique identifier of another calendar component. This value would be
represented in a calendar component by the "UID" property.

By default, the property value points to another calendar component
that has a PARENT relationship to the referencing object. The
"RELTYPE" property parameter is used to either explicitly state the
default PARENT relationship type to the referenced calendar component
or to override the default PARENT relationship type and specify
either a CHILD or SIBLING relationship. The PARENT relationship
indicates that the calendar component is a subordinate of the
referenced calendar component. The CHILD relationship indicates that
the calendar component is a superior of the referenced calendar
component. The SIBLING relationship indicates that the calendar
component is a peer of the referenced calendar component.

Changes to a calendar component referenced by this property MAY can have
an implied implicit impact to on the related calendar component. For example, if
a group event changes its start or end date or time, then the
related, dependent events will need to have their start and end dates
changed in a corresponding way. Similarly, if a PARENT calendar
component is canceled or deleted, then there is an implied impact to
the related CHILD calendar components. This property is intended only
to provide information on the relationship of calendar components. It
is up to the target calendar system to maintain any property
implications of this relationship.

Only the property specific "RELTYPE" parameter MAY be specified on
this property.

Format Definition: The property is defined by the following notation:

related = "RELATED-TO" [";" [WSP] relparam) [relparam] ":" [WSP] text CRLF

relparam = "RELTYPE" "="
"PARENT" ; Parent relationship. Default.
/ "CHILD" ; Child relationship.
/ "SIBLING" ; Sibling relationship. [";" reltypeparam]
*(";" xparm)

The following is an example of this property:

RELATED-TO:<jsmith.part7.19960817T083000.xyzMail@host3.com>

RELATED-TO:<19960401-080045-4000F192713-0052@host1.com>

4.8.4.6 Uniform Resource Locator

Property Name: URL

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Purpose: This property defines a Uniform Resource Locator (URL)
associated with the iCalendar object.

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Value Type: URI

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This property MAY can be specified once in the "VEVENT",
"VTODO", "VJOURNAL" and "VFREEBUSY" calendar components.

Description: This property may be used in a calendar component to
convey a location where a more dynamic rendition of the calendar
information associated with the calendar component can be found. This
memo does not attempt to standardize the form of the URI, nor the
format of the resource pointed to by the property value. If the

No URL
property parameter MAY be specified on this property. and Content-Location MIME header are both specified, they
MUST point to the same resource.

Format Definition: The property is defined by the following notation:

url = "URL" urlparam ":" [WSP] uri CRLF

urlparam = *(";" xparam)

Example: The following is an example of this property:

URL:http://abc.com/pub/calendars/jsmith/mytime.or3

URL:http://abc.com/pub/calendars/jsmith/mytime.ics

4.8.4.7 Unique Identifier

Property Name: UID

Purpose: This property defines the persistent, globally unique
identifier for the calendar component.

Value Type: TEXT

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: The property MUST be specified in the "VEVENT", "VTODO",
"VJOURNAL" and "VFREEBUSY" calendar components.

Description: The UID itself MUST be a globally unique identifier. The
generator of the identifier MUST guarantee that the identifier is
unique. There are several algorithms that can be used to accomplish
this. The identifier is RECOMMENDED to be the identical syntax to the
[RFC 822] addr-spec. A good method to assure uniqueness is to put the
domain name or a domain literal IP address of the host on which the
identifier was created on the right hand side of the "@", and on the
left hand side, put a combination of the current calendar date and
time of day (i.e., formatted in as a DATE-TIME value) along with some
other currently unique (perhaps sequential) identifier available on
the system (for example, a process id number). Using a date/time
value on the left hand side and a domain name or domain literal on
the right hand side makes it possible to guarantee uniqueness since

Dawson/Stenerson 90 Expires November 1998

Internet Draft C&S Core Object Specification April 30, 1998

no two hosts should be using the same domain name or IP address at
the same time. Though other algorithms will work, it is RECOMMENDED
that the right hand side contain some domain identifier (either of
the host itself or otherwise) such that the generator of the message

Dawson/Stenerson 81 Expires September 1998

Internet Draft C&S Core Object Specification March 6, 1998