WDIFF

draft-ietf-calsify-rfc2445bis-00.txt --> draft-ietf-calsify-rfc2445bis-01.txt

Network Working Group B. Desruisseaux, Ed.
Internet-Draft Oracle
Obsoletes: 2445 (if approved) June 22, 2006
Expires: April 14, December 24, 2006 C. Stoner, Ed.
IBM
October 11, 2005

Internet Calendaring and Scheduling Core Object Specification
(iCalendar)
draft-ietf-calsify-rfc2445bis-00
draft-ietf-calsify-rfc2445bis-01

Status of this Memo

By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.

Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."

The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.

The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.

This Internet-Draft will expire on April 14, December 24, 2006.

Abstract

Calendar systems export, transport and sometimes even store calendar
information in

There is a standard, clear need to provide and deploy interoperable format. 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 defines
has been defined to provide the definition of a common format for
openly exchanging calendaring and scheduling information across the Internet,
Internet.

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This memo is formatted as a registration for a MIME media type .
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'. 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
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.

This memo defines the format for specifying iCalendar object
format. methods.
An iCalendar object may represent 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, to-do 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 task, busy time
request, or provide similar scheduling messages for a to-do or
journal entry (note).

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Internet-Draft calendar component. The iCalendar October 2005 Transport-indendent
Interoperability Protocol (iTIP) is one such scheduling protocol.

Editorial Note

This document is a product of the Calendaring and Scheduling
Standards Simplification (Calsify) working group of the Internet
Engineering Task Force. Comments on this draft are solicited welcomed, and
should be addressed to the working group's ietf-calsify@osafoundation.org [1] mailing
list.

A detailed list of changes is available at ietf-calsify@osafoundation.org and/or the editor. following page:
http://www.geocities.com/bdesruisseaux/calsify/
draft-ietf-calsify-rfc2445bis-01.html.

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Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1. Related Memos 6
2. Basic Grammar and Conventions . . . . . . . . . . . . . . . . 6
2.1. Formatting Conventions . . . . . . 5
2. Overview . . . . . . . . . . . 7
2.2. Related Memos . . . . . . . . . . . . . . . 7
3. Document Conventions . . . . . . . 8
2.3. International Considerations . . . . . . . . . . . . . . 8
3.1. Formatting Conventions
3. iCalendar Object Specification . . . . . . . . . . . . . . . 9
3.1. Content Lines . . 8
4. International Considerations . . . . . . . . . . . . . . . . 10
5. General Syntax . . . . 9
3.1.1. List and Field Separators . . . . . . . . . . . . . . 11
3.1.2. Multiple Values . . . . . 11
5.1. Character Set . . . . . . . . . . . . . . 12
3.1.3. Binary Content . . . . . . . 11
5.2. Case Sensitivity . . . . . . . . . . . . 12
3.1.4. Character Set . . . . . . . . 11
5.3. Content Lines . . . . . . . . . . . . 13
3.2. Property Parameters . . . . . . . . . 11
5.4. List and Field Separators . . . . . . . . . . 13
3.2.1. Alternate Text Representation . . . . . 14
5.5. Multiple Property Values . . . . . . . 14
3.2.2. Common Name . . . . . . . . . 14
5.6. Binary Content . . . . . . . . . . . . 15
3.2.3. Calendar User Type . . . . . . . . . 15
5.7. Property Parameter Syntax . . . . . . . . 16
3.2.4. Delegators . . . . . . . 15
6. iCalendar Objects . . . . . . . . . . . . . . 16
3.2.5. Delegatees . . . . . . . . 17
7. Calendar Components . . . . . . . . . . . . . 17
3.2.6. Directory Entry Reference . . . . . . . . 18
7.1. Event Component . . . . . . 17
3.2.7. Inline Encoding . . . . . . . . . . . . . . 19
7.2. To-do Component . . . . . 18
3.2.8. Format Type . . . . . . . . . . . . . . . 22
7.3. Journal Component . . . . . . 19
3.2.9. Free/Busy Time Type . . . . . . . . . . . . . 24
7.4. Free/Busy Component . . . . 19
3.2.10. Language . . . . . . . . . . . . . . 26
7.5. Time Zone Component . . . . . . . . 20
3.2.11. Group or List Membership . . . . . . . . . . 29
7.6. Alarm Component . . . . 21
3.2.12. Participation Status . . . . . . . . . . . . . . . . 38
8. Properties 21
3.2.13. Recurrence Identifier Range . . . . . . . . . . . . . 23
3.2.14. Alarm Trigger Relationship . . . . . . . . . . . . 45
8.1. Calendar Properties . 23
3.2.15. Relationship Type . . . . . . . . . . . . . . . . . 45
8.1.1. Calendar Scale . 24
3.2.16. Participation Role . . . . . . . . . . . . . . . . . 25
3.2.17. RSVP Expectation . 45
8.1.2. Method . . . . . . . . . . . . . . . . . 25
3.2.18. Sent By . . . . . . 46
8.1.3. Product Identifier . . . . . . . . . . . . . . . . . 47
8.1.4. Version 26
3.2.19. Time Zone Identifier . . . . . . . . . . . . . . . . 26
3.2.20. Value Data Types . . . . . . . 48
8.2. Descriptive Component Properties . . . . . . . . . . . 28
3.3. Property Value Data Types . 49
8.2.1. Attachment . . . . . . . . . . . . . . . 29
3.3.1. Binary . . . . . . 49
8.2.2. Categories . . . . . . . . . . . . . . . . . 29
3.3.2. Boolean . . . . 50
8.2.3. Classification . . . . . . . . . . . . . . . . . . . 51
8.2.4. Comment 30
3.3.3. Calendar User Address . . . . . . . . . . . . . . . . 30
3.3.4. Date . . . . . . . 52
8.2.5. Description . . . . . . . . . . . . . . . . . 31
3.3.5. Date-Time . . . . 53
8.2.6. Geographic Position . . . . . . . . . . . . . . . . . 54
8.2.7. Location . 31
3.3.6. Duration . . . . . . . . . . . . . . . . . . . . . 56
8.2.8. Percent Complete . 34
3.3.7. Float . . . . . . . . . . . . . . . . . 57
8.2.9. Priority . . . . . . . 34
3.3.8. Integer . . . . . . . . . . . . . . . 58
8.2.10. Resources . . . . . . . . 35
3.3.9. Period of Time . . . . . . . . . . . . . . 59
8.2.11. Free/Busy Time Type . . . . . 35
3.3.10. Recurrence Rule . . . . . . . . . . . . 60
8.2.12. Participation Status . . . . . . . 37
3.3.11. Text . . . . . . . . . 61
8.2.13. Status . . . . . . . . . . . . . . . 42
3.3.12. Time . . . . . . . . 63

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8.2.14. Summary . . . . . . . . . . . . . . . . 43
3.3.13. URI . . . . . . . 64
8.2.15. Date and Time Component Properties . . . . . . . . . 65
8.2.16. Time Zone Component Properties . . . . . . . . . 46

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3.3.14. UTC Offset . . 73
8.2.17. Relationship Component Properties . . . . . . . . . . 77
8.2.18. Calendar User Type . . . . . . . . . 46
3.4. iCalendar Object . . . . . . . . 86
8.2.19. Directory Entry Reference . . . . . . . . . . . . 47
3.5. Property . . 87
8.2.20. Recurrence ID . . . . . . . . . . . . . . . . . . . . 87
8.2.21. Related To . . 48
3.6. Calendar Components . . . . . . . . . . . . . . . . . . . 89
8.2.22. Uniform Resource Locator 48
3.6.1. Event Component . . . . . . . . . . . . . . 91
8.2.23. Unique Identifier . . . . . 49
3.6.2. To-do Component . . . . . . . . . . . . . 91
8.2.24. Relationship Type . . . . . . 52
3.6.3. Journal Component . . . . . . . . . . . . 93
8.3. Recurrence Component Properties . . . . . . 54
3.6.4. Free/Busy Component . . . . . . 94
8.3.1. Exception Date/Times . . . . . . . . . . . 55
3.6.5. Time Zone Component . . . . . 94
8.3.2. Exception Rule . . . . . . . . . . . . 58
3.6.6. Alarm Component . . . . . . . 95
8.3.3. Recurrence Date/Times . . . . . . . . . . . . 66
3.7. Calendar Properties . . . . 97
8.3.4. Recurrence Identifier Range . . . . . . . . . . . . . 98
8.3.5. Recurrence Rule . . 72
3.7.1. Calendar Scale . . . . . . . . . . . . . . . . . 99
8.4. Alarm Component Properties . . 72
3.7.2. Method . . . . . . . . . . . . . 110
8.4.1. Action . . . . . . . . . . 73
3.7.3. Product Identifier . . . . . . . . . . . . . 110
8.4.2. Alarm Repeat Count . . . . 74
3.7.4. Version . . . . . . . . . . . . . 111
8.4.3. Alarm Trigger . . . . . . . . . . 75
3.8. Component Properties . . . . . . . . . . 111
8.5. Alarm Trigger Relationship . . . . . . . . 76
3.8.1. Descriptive Component Properties . . . . . . . 114
8.6. Change Management Component Properties . . . 76
3.8.1.1. Attachment . . . . . . 114
8.6.1. Date/Time Created . . . . . . . . . . . . . 76
3.8.1.2. Categories . . . . . 114
8.6.2. Date/Time Stamp . . . . . . . . . . . . . . 77
3.8.1.3. Classification . . . . . 115
8.6.3. Last Modified . . . . . . . . . . . . 78
3.8.1.4. Comment . . . . . . . . 116
8.6.4. Sequence Number . . . . . . . . . . . . . 79
3.8.1.5. Description . . . . . . 117
8.7. Miscellaneous Component Properties . . . . . . . . . . . 118
8.7.1. RSVP Expectation . . 80
3.8.1.6. Geographic Position . . . . . . . . . . . . . . . 81
3.8.1.7. Location . 118
8.7.2. Language . . . . . . . . . . . . . . . . . . . 83
3.8.1.8. Percent Complete . . . 119
8.7.3. Group or List Membership . . . . . . . . . . . . . 84
3.8.1.9. Priority . 120
8.7.4. Alternate Text Representation . . . . . . . . . . . . 121
8.7.5. Inline Encoding . . . . . . . 85
3.8.1.10. Resources . . . . . . . . . . . . 121
8.7.6. Format Type . . . . . . . . 87
3.8.1.11. Status . . . . . . . . . . . . . 122
8.7.7. Non-standard Properties . . . . . . . . 87
3.8.1.12. Summary . . . . . . . 123
8.7.8. Request Status . . . . . . . . . . . . . . 89
3.8.2. Date and Time Component Properties . . . . . 124
9. iCalendar Object Examples . . . . 90
3.8.2.1. Date/Time Completed . . . . . . . . . . . . . . 127
10. Recommended Practices . 90
3.8.2.2. Date/Time End . . . . . . . . . . . . . . . . . . 91
3.8.2.3. Date/Time Due . 132
11. Registration of Content Type Elements . . . . . . . . . . . . 134
11.1. Registration of New and Modified iCalendar Object
Methods . . . . . 92
3.8.2.4. Date/Time Start . . . . . . . . . . . . . . . . . 93
3.8.2.5. Duration . . 134
11.2. Registration of New Properties . . . . . . . . . . . . . 134
11.3. Define the property . . . . . 94
3.8.2.6. Free/Busy Time . . . . . . . . . . . . . 134
11.4. Post the Property definition . . . . 95
3.8.2.7. Time Transparency . . . . . . . . . . 136
11.5. Allow a comment period . . . . . . 96
3.8.3. Time Zone Component Properties . . . . . . . . . . . 136
11.6. Submit the property for approval 97
3.8.3.1. Time Zone Identifier . . . . . . . . . . . . 136
11.7. Property Change Control . . 98
3.8.3.2. Time Zone Name . . . . . . . . . . . . . . 136
12. Property Parameters . . . 99
3.8.3.3. Time Zone Offset From . . . . . . . . . . . . . . 100
3.8.3.4. Time Zone Offset To . . . . 138

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13. Value Data Types . . . . . . . . . . . 101
3.8.3.5. Time Zone URL . . . . . . . . . . . 139
13.1. Binary . . . . . . . 101
3.8.4. Relationship Component Properties . . . . . . . . . . 102
3.8.4.1. Attendee . . . . . . . . 139
13.2. Boolean . . . . . . . . . . . . 102
3.8.4.2. Contact . . . . . . . . . . . . 140
13.3. Calendar User Address . . . . . . . . . 105
3.8.4.3. Organizer . . . . . . . . 140
13.4. Date . . . . . . . . . . . . 106
3.8.4.4. Recurrence ID . . . . . . . . . . . . . . 141
13.5. Date-Time . . . . 108

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3.8.4.5. Related To . . . . . . . . . . . . . . . . . . . 141
13.6. Duration 110
3.8.4.6. Uniform Resource Locator . . . . . . . . . . . . 112
3.8.4.7. Unique Identifier . . . . . . . . . . . . 143
13.7. Period of Time . . . . 112
3.8.5. Recurrence Component Properties . . . . . . . . . . . 114
3.8.5.1. Exception Date/Times . . . . . . 144
13.8. Time Zone Identifier . . . . . . . . 114
3.8.5.2. Exception Rule . . . . . . . . . . 145
13.9. Recurrence Rule . . . . . . . 115
3.8.5.3. Recurrence Date/Times . . . . . . . . . . . . . 146
13.10. Float . 117
3.8.5.4. Recurrence Rule . . . . . . . . . . . . . . . . . 118
3.8.6. Alarm Component Properties . . . . . . . 152
13.11. Integer . . . . . . 127
3.8.6.1. Action . . . . . . . . . . . . . . . . . . 152
13.12. Text . . . 128
3.8.6.2. Repeat Count . . . . . . . . . . . . . . . . . . 128
3.8.6.3. Trigger . . . . . 153
13.13. Time . . . . . . . . . . . . . . . . 129
3.8.7. Change Management Component Properties . . . . . . . 131
3.8.7.1. Date/Time Created . . . . 154
13.14. URI . . . . . . . . . . . . 132
3.8.7.2. Date/Time Stamp . . . . . . . . . . . . . . 156
13.15. UTC Offset . . . 132
3.8.7.3. Last Modified . . . . . . . . . . . . . . . . . . 133
3.8.7.4. Sequence Number . . . . . . . . . . . . . . . . . 134
3.8.8. Miscellaneous Component Properties . . . . . . . . . 136
3.8.8.1. Non-standard Properties . . . . . . . . . . . . . 136
3.8.8.2. Request Status . . . . . . . . . . . . . . . . . 137
4. iCalendar Object Examples . . . . . . . . . . . . . . . . . . 140
5. Recommended Practices . . . . . . . . . . . . . . . . . . . . 144
6. Registration of Content Type Elements . . . . . . . . . . . . 145
6.1. Registration of New and Modified iCalendar Object
Methods . . . . . . . . . . . . . . . . . . . . . . . . . 145
6.2. Registration of New Properties . . . . . . . . . . . . . 145
6.2.1. Define the property . . . . . . . . . . . . . . . . . 146
6.2.2. Post the Property definition . . . . . . . . . . . . 147
6.2.3. Allow a comment period . . . . . . . . . . . . . . . 147
6.2.4. Submit the property for approval . . . . . . . . . . 147
6.3. Property Change Control . . . . . . . . . . . . . . . . . 148
7. Internationalization Considerations . . . . . . . . . . 157
14. . . . 148
8. Security Considerations . . . . . . . . . . . . . . . . . . . 159
15. 148
9. IANA MIME Consideration . . . . . . . . . . . . . . . . . . . . . 149
9.1. Media Type Registration Information . . . . . . . . . . . 149
10. Acknowledgments . . . . . . . . . . . . . . . . . . 160
16. Acknowledgements . . . . . 152
11. References . . . . . . . . . . . . . . . . . . . . . . 163
17. . . . 152
11.1. Normative References . . . . . . . . . . . . . . . . . . 152
11.2. Informative References . . . . . . . . . . . . . . . . . 153
Author's Address . 163
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 165 155
Intellectual Property and Copyright Statements . . . . . . . . . 166 156

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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 [5] 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 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. [[Comment.1: Removed forward
reference to ITIP (unnecessary) --Lisa D]] Such a scheduling protocol is
defined in the iCalendar Transport-independent Interoperability
Protocol (iTIP) defined in [I-D.ietf-calsify-2446bis].

The memo also includes a formal grammar for the content type based on
the Internet ABNF defined in RFC 2234 [8]. [RFC2234]. 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.

1.1. Related Memos

Implementers will need to be familiar with several other memos that,
along with this memo, form a framework for Internet calendaring

2. Basic Grammar and
scheduling standards. This memo, [ICAL], specifies a core
specification of objects, data types, properties Conventions

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

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parameters.

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

[IMIP] specifies an Internet email 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. [[Comment.2: If we keep this section on
related memos, we have to think about whether ITIP and IMIP are
progressing to Draft at the same time, whether to update those
references and whether to add CalDAV or other references. --Lisa D]]

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2. Overview

This draft section provides a high-level overview of the concepts of
iCalendar and the organization of this document.

An iCalendar object contains a set of calendar properties and a set
of components. Components consist of a set of component properties.
Properties consist of a property name, a set of parameters, and a
property value.

The preliminary material of this document includes the introduction,
this overview, some document conventions and the considerations for
internationalization.

Section 5 provides the general syntax rules used by all of iCalendar,
such as character set, line length and line break rules, and which
characters are separators.

Section 6 defines the iCalendar object itself, and Section 7 covers
the components that appear in iCalendar objects.

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3. Document Conventions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY" and
"OPTIONAL" in this document are to be interoperated as described in
RFC 2119 [7]. June 2006

"OPTIONAL" in this document are to be interoperated as described in
[RFC2119].

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 [8]. [RFC2234].
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 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. 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 is not essential to the building of an implementation
conformant with this memo. The information is provided to
highlight a particular feature or characteristic of the memo. [[Comment.3: This section can
be deleted because it provides practically no information and is not
a normative reference:

The format for the iCalendar object is based on the syntax of the RFC 2425
[RFC2425] content type. While the iCalendar object is not a profile
of the RFC 2425 [RFC2425] content type, it does reuse a number of the elements
from the RFC 2425 [RFC2425] specification. --Lisa D]]

3.1.

2.1. Formatting Conventions

The mechanisms defined in this memo are defined in 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, core
object (this memo) or interoperability protocol [ITIP] [I-D.ietf-calsify-
2446bis] some formatting conventions have been used. Calendaring and
scheduling roles 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]. [I-D.ietf-calsify-2446bis]. 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] iTIP
[I-D.ietf-calsify-2446bis] are referred to with capitalized, quoted-strings quoted-
strings of text. For example, "REQUEST" refers to the method for

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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 lowercase, quoted-strings
of text, 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.

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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 specifies a core specification of
objects, data types, properties and property parameters.

o iTIP [I-D.ietf-calsify-2446bis] specifies an interoperability
protocol for scheduling between different implementations;

o iMIP [I-D.ietf-calsify-rfc2447bis] specifies an Internet email
binding for [I-D.ietf-calsify-2446bis].

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.

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5. General Syntax

5.1. Character Set

The default character set for an June 2006

3. iCalendar object is UTF-8 as defined
in RFC 2279 [9]. Object Specification

The "charset" Content-Type parameter 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 can be used in
MIME transports to specify any other IANA registered character set.
[[Comment.4: I think we need to say something about interoperability
problems which result from using any other charset. --Lisa D]]

5.2. Case Sensitivity

All names independent 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.

5.3. 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.

3.1. Content Lines

The iCalendar object is organized into individual lines of text,
called content lines. Content lines are delimited by a line break,
which is a CRLF sequence (US-ASCII decimal 13, followed by US-ASCII
decimal 10).

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

Figure 1

Can be represented as:

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

Figure 2

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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 octets SHOULD be
folded according to the folding procedure described above. Content
lines are CRLF-separated. [[Comment.5: Removed reference

The content information associated with an iCalendar object is

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formatted using a syntax similar to 2425
again and simply stated that lines are defined by [RFC2425]. That
is, the content information consists of CRLF-separated --Lisa]] content lines.

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

contentline = name *(";" 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 octets SHOULD be folded according to
; the folding procedure described above.

name = x-name / iana-token

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

x-name = "X-" [vendorid "-"] 1*(ALPHA / DIGIT / "-")
; Reservered Reserved 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

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value = *VALUE-CHAR

quoted-string = DQUOTE *QSAFE-CHAR DQUOTE

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

QSAFE-CHAR = WSP / %x21 / %x23-7E / NON-US-ASCII

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; Any character except CTLs and DQUOTE

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

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

CR = %x0D
; carriage return

LF = %x0A
; line feed

CRLF = CR LF
; Internet standard newline

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

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

DIGIT = %x30-39
; 0-9

DQUOTE = %x22
; Quotation Mark

WSP = SPACE / HTAB

SPACE = %x20

HTAB = %x09

Figure 3

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

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a definition of this format.

5.4.

3.1.1. List and Field Separators

Some properties and parameters allow a list of values. Values in a
list of values MUST be separated by a COMMA character (US-ASCII

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decimal 44). There is no significance to the order 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 parts. These
structured property values MUST have their value parts separated by a
SEMICOLON character (US-ASCII decimal 59).

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

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

For example, in the following properties a SEMICOLON is used to
separate property parameters from each other, and a COMMA is used to
separate property values in a value list.

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

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

5.5.

3.1.2. Multiple Property Values

Some properties defined in the iCalendar object can have multiple
values. The general rule for encoding multi-valued items is to
simply create a new content line for each 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 (US-ASCII decimal 44). Individual
property definitions should be consulted for determining whether a
specific property allows multiple values and in which of these two
forms.

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5.6.

3.1.3. 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
can be included within an iCalendar object, but only after first
encoding it into text using the "BASE64" encoding method defined in
[RFC 2045].
[RFC2045]. Inline binary contact SHOULD only be used in applications
whose special circumstances demand that an iCalendar object be

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expressed as a single entity. 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

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

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

ATTACH;FMTTYPE=image/basic;ENCODING=BASE64;VALUE=BINARY:
MIICajCCAdOgAwIBAgICBEUwDQYJKoZIhvcNAQEEBQAwdzELMAkGA1U
EBhMCVVMxLDAqBgNVBAoTI05ldHNjYXBlIENvbW11bmljYXRpb25zIE
[...remainder
<...remainder of "BASE64" encoded binary data...]

5.7. data...>

3.1.4. 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 as defined in [RFC2279].

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

3.2. Property Parameter Syntax Parameters

A property can have attributes associated with it. These "property
parameters" contain meta-information about the property or the
property value. Property parameters 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, the data type
of the property value and other attributes.

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

DESCRIPTION;ALTREP="http://www.wiz.org":The Fall'98 Wild Wizards

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Conference - - Las Vegas, NV, USA

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

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6. iCalendar Objects

The Calendaring and Scheduling Core Object is a collection of
calendaring and scheduling information. Typically, general property parameters defined by 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 = 1*("BEGIN" ":" "VCALENDAR" CRLF
icalbody
"END" ":" "VCALENDAR" CRLF)

Figure 8

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

Figure 9

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7. Calendar Components

The body of an iCalendar object consists of a sequence of calendar
properties and one or more calendar components. The calendar
properties are attributes that apply to the calendar as a whole. The
calendar components memo are collections of properties that express a
particular calendar semantic. For example, the calendar component
can specify an event, a to-do, a journal entry, time zone
information, or free/busy time information, or an alarm.

The body of the iCalendar object is defined by
the following notation:

icalbody = calprops component

calprops

parameter = 2*(

; 'prodid' and 'version' are both REQUIRED, altrepparam ; but MUST NOT occur more than once

prodid /version Alternate text representation
/ cnparam ; 'calscale' and 'method' are optional,
; but MUST NOT occur more than once

calscale Common name
/
method cutypeparam ; Calendar user type
/

x-prop

)

component = 1*(eventc delfromparam ; Delegator
/ todoc deltoparam ; Delegatee
/ journalc dirparam ; Directory entry
/ freebusyc encodingparam ; Inline encoding
/ fmttypeparam ; Format type
/ timezonec fbtypeparam ; Free/busy time type
/ iana-comp languageparam ; Language for text
/ x-comp)

iana-comp 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
/ valuetypeparam ; Property value data type
/ ianaparam
; Some other IANA registered iCalendar parameter.
/ xparam
; A non-standard, experimental parameter.

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

1*contentline

"END" ":" iana-token CRLF

x-comp "=" param-value *("," param-value)

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

1*contentline

"END" ":" x-name CRLF "=" param-value *("," param-value)

3.2.1. Alternate Text Representation

Parameter Name: ALTREP

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

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

altrepparam = "ALTREP" "=" DQUOTE uri DQUOTE

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Figure 10

An iCalendar object June 2006

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 "PRODID" and "VERSION" calendar
properties. In addition, it default representation of the text value. The individual URI
parameter values MUST each be specified in a quoted-string.

Example:

DESCRIPTION;ALTREP="CID:<part3.msg.970415T083000@host.com>":Project
XYZ Review Meeting will include at least one calendar
component. Special forms of iCalendar objects are possible the following agenda items: (a)
Market Overview, (b) Finances, (c) Project Management

The "ALTREP" property parameter value might point to
publish just busy time (i.e., only a "VFREEBUSY" "text/html"
content portion.

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:<ol><li>Market
Overview</li><li>Finances</li><li>Project Management</li></ol></p>
</body></html>

3.2.2. Common Name

Parameter Name: CN

Purpose: To specify the common name to be associated with the
calendar component)
or time zone (i.e., only user specified by the property.

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

cnparam = "CN" "=" param-value

Description: This parameter can be specified on properties with a "VTIMEZONE"
CAL-ADDRESS value type. The parameter specifies the common name
to be associated with the calendar component)
information. In addition, a complex iCalendar object is possible
that user specified by the property.
The parameter value is text. The parameter value can be used for
display text to capture a complete snapshot of be associated with the contents of a
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.

7.1. Event Component

Component Name: VEVENT

Purpose: Provide a grouping of component properties that describe an
event. address specified
by the property.

Example:

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

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Formal Definition: A "VEVENT" June 2006

3.2.3. Calendar User Type

Parameter Name: CUTYPE

Purpose: To specify the type of calendar component user specified by the
property.

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

eventc = "BEGIN" ":" "VEVENT" CRLF
eventprop *alarmc
"END" ":" "VEVENT" CRLF

eventprop

cutypeparam = *(

; the following are optional, "CUTYPE" "="
("INDIVIDUAL" ; but MUST NOT occur more than once

class / created An individual
/ description / dtstart / geo /

last-mod / location / organizer / priority /
dtstamp / seq / status / summary / transp /
uid / url / recurid "GROUP" ; A group of individuals
/ "RESOURCE" ; either 'dtend' or 'duration' may appear in A physical resource
/ "ROOM" ; a 'eventprop', but 'dtend' and 'duration' A room resource
/ "UNKNOWN" ; MUST NOT occur in the same 'eventprop'

dtend Otherwise not known
/ duration x-name ; Experimental type
/ iana-token) ; the following are optional, Other IANA registered
; and MAY occur more than once

attach / attendee / categories / comment /
contact / exdate / exrule / rstatus / related /
resources / rdate / rrule / x-prop

)

Figure 11

Description: A "VEVENT" calendar component type
; Default is a grouping of component
properties, and possibly including "VALARM" calendar components, that
represents a scheduled amount of time on a calendar. For example, it INDIVIDUAL

Description: This parameter 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 specified on an individual calendar. Hence, the event will appear as an opaque
interval in properties with a search for busy time. Alternately, the event can have
its Time Transparency set to "TRANSPARENT" in order to prevent
blocking of the event in searches for busy time.
CAL-ADDRESS value type. The "VEVENT" is also parameter identifies the calendar component used to specify an
anniversary or daily reminder within a calendar. These events have a

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DATE value type for the "DTSTART" property instead of
calendar user specified by the default
data type of DATE-TIME. property. If such a "VEVENT" has a "DTEND" property,
it MUST be not specified as a DATE value also. The anniversary type of
"VEVENT" can span more than one date (i.e, "DTEND" property value is
set to on a calendar date after the "DTSTART" property value).

The "DTSTART"
property for a "VEVENT" specifies that allows this parameter, the inclusive start
of default is INDIVIDUAL.

Example:

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

3.2.4. Delegators

Parameter Name: DELEGATED-FROM

Purpose: To specify the event. For recurring events, it also specifies calendar users that have delegated their
participation to the very first
instance in calendar user specified by the recurrence set. property.

Format Definition: The "DTEND" property for a "VEVENT"
calendar component specifies the non-inclusive end of parameter is defined by the event. For
cases where following
notation:

delfromparam = "DELEGATED-FROM" "=" DQUOTE cal-address DQUOTE
*("," DQUOTE cal-address DQUOTE)

Description: This parameter can be specified on properties with a "VEVENT" calendar component specifies
CAL-ADDRESS value type. This parameter can be specified on a "DTSTART"
property with that has a DATE data value type but no "DTEND" property, the events
non-inclusive end is the end of the calendar date specified by the
"DTSTART" property. For cases where a "VEVENT" calendar component address. This
parameter specifies those calendar users that have delegated their
participation in a "DTSTART" property with a DATE-TIME data type but no
"DTEND" property, the group scheduled event ends on or to-do to the same calendar date and time
of day

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user specified by the "DTSTART" property. The "VEVENT" calendar component cannot value MUST be nested within another
calendar component. However, "VEVENT" calendar components can be
related to a MAILTO URI as
defined in [RFC1738]. The individual calendar address parameter
values MUST each other or to be specified in a "VTODO" or quoted-string.

Example:

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

3.2.5. Delegatees

Parameter Name: DELEGATED-TO

Purpose: To specify the calendar users to a "VJOURNAL" whom the calendar
component with user
specified by the "RELATED-TO" property.

Example 1: property has delegated participation.

Format Definition: The following property parameter is an example of defined by the "VEVENT" following
notation:

deltoparam = "DELEGATED-TO" "=" DQUOTE cal-address DQUOTE
*("," DQUOTE cal-address DQUOTE)

Description: This parameter can be specified on properties with a
CAL-ADDRESS value type. This parameter specifies those calendar
component used to represent
users whom have been delegated participation in a meeting that will also be opaque 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

Figure 12

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Example 2: The following is an example of group scheduled
event or to-do by the "VEVENT" calendar
component used to represent a reminder that will not user specified by the property.
The value MUST be opaque, but
rather transparent, to searches for busy time:

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

Figure 13

Example 3: [RFC1738]. The following is an example of the "VEVENT"
individual calendar
component used to represent an anniversary that will occur annually.
Since it takes up no time, it will not appear as opaque address parameter values MUST each be
specified in a search
for busy time; no matter what the value of 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

Figure 14

7.2. To-do Component

Component quoted-string.

Example:

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

3.2.6. Directory Entry Reference

Parameter Name: VTODO DIR

Purpose: Provide To specify reference to a grouping of directory entry associated with
the calendar properties that describe a
to-do. user specified by the property.

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

dirparam = "DIR" "=" DQUOTE uri DQUOTE

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Formal Definition: A "VTODO" June 2006

Description: This parameter can be specified on properties with a
CAL-ADDRESS value type. The parameter specifies a reference to
the directory entry associated with the calendar component user specified by
the property. The parameter value is a URI. The individual URI
parameter values MUST each be specified in a quoted-string.

Example:

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

3.2.7. Inline Encoding

Parameter Name: ENCODING

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

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

todoc = "BEGIN" ":" "VTODO" CRLF
todoprop *alarmc
"END" ":" "VTODO" CRLF

todoprop

encodingparam = *(

; the following are optional,
; but MUST NOT occur more than once

class / completed / created / description / dtstamp /
dtstart / geo / last-mod / location / organizer /
percent / priority / recurid / seq / status /
summary / uid / url / "ENCODING" "="
("8BIT"
; either 'due' or 'duration' may appear "8bit" text encoding is defined in [RFC2045]
/ "BASE64"
; a 'todoprop', but 'due' and 'duration'
; MUST NOT occur "BASE64" binary encoding format is defined in the same 'todoprop'

due [RFC2045]
/ duration iana-token
; Some other IANA registered iCalendar encoding type
/ x-name)
; the following are optional,
; and MAY occur more than once
attach / attendee / categories / comment / contact /
exdate / exrule / rstatus / related / resources /
rdate / rrule / x-prop

)

Figure 15

Description: A "VTODO" calendar component is a grouping of component
properties and possibly "VALARM" calendar components that represent
an action-item or assignment. For example, it can be non-standard, experimental encoding type

Description: The property parameter identifies the inline encoding
used to
represent an item of work assigned to an individual; such as "turn in
travel expense today". a property value. The "VTODO" calendar component cannot be nested within another
calendar component. However, "VTODO" calendar components can be
related to each other or default encoding is "8BIT",
corresponding to a "VTODO" or property value consisting of text. The
"BASE64" encoding type corresponds to a "VJOURNAL" calendar
component with property value encoded
using the "RELATED-TO" property.

A "VTODO" calendar component without "BASE64" encoding defined in [RFC2045].

If the "DTSTART" and "DUE" (or
"DURATION") properties specifies a to-do that will value type parameter is ";VALUE=BINARY", then the inline
encoding parameter MUST be associated specified with
each successive calendar date, until it is completed. the value
";ENCODING=BASE64".

Example:

ATTACH;FMTYPE=IMAGE/JPEG;ENCODING=BASE64;VALUE=BINARY:MIICajC
CAdOgAwIBAgICBEUwDQYJKoZIhvcNAQEEBQAwdzELMAkGA1UEBhMCVVMxLDA
qBgNVBAoTI05ldHNjYXBlIENvbW11bmljYXRpb25zIENvcnBvcmF0aW9uMRw
<...remainder of "BASE64" encoded binary data...>

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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:VTODO

Figure 16

7.3. Journal Component

Component June 2006

3.2.8. Format Type

Parameter Name: VJOURNAL FMTTYPE

Purpose: Provide a grouping To specify the content type of component properties that describe a
journal entry.

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Formal referenced object.

Format Definition: A "VJOURNAL" calendar component The property parameter is defined by the following
notation:

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

jourprop

fmttypeparam = *(

; the following are optional, "FMTTYPE" "=" iana-token
; but MUST NOT occur more than once

class / created / description / dtstart / dtstamp /
last-mod / organizer / recurid / seq / status /
summary / uid / url A IANA registered content type
/ x-name
; the following are optional,
; and MAY occur more than once

attach / attendee / categories / comment /
contact / exdate / exrule / related / rdate /
rrule / rstatus / x-prop

)

Figure 17

Description: A "VJOURNAL" calendar component is a grouping of
component non-standard content type

Description: This parameter can be specified on properties that represent one or more descriptive text
notes associated with a particular calendar date. The "DTSTART"
property is are
used to specify reference an object. The parameter specifies the calendar date that content
type of the journal entry
is associated with. Generally, it will have a DATE value data type,
but it can also be used to specify referenced object. For example, on the "ATTACH"
property, a DATE-TIME FTP type URI 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 does not, by itself, necessarily
convey the day
or an ordered list type of accomplishments for content associated with the day. resource. The "VJOURNAL"
calendar component can also
parameter value MUST be used to associate a document with a
calendar date.

The "VJOURNAL" calendar component does not take up time on a
calendar. Hence, it does not play the TEXT for either an IANA registered
content type or a role in non-standard content type.

Example:

ATTACH;FMTTYPE=application/msword:ftp://domain.com/pub/docs/
agenda.doc

3.2.9. Free/Busy Time Type

Parameter Name: FBTYPE

Purpose: To specify the free or busy time
searches - - it type.

Format Definition: The property parameter is as though it has a defined by the following
notation:

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

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Description: The parameter specifies the free or busy time transparency type. The
value of
TRANSPARENT. It FREE indicates that the time interval is transparent to any such searches. free for
scheduling. The "VJOURNAL" calendar component cannot be nested within another
calendar component. However, "VJOURNAL" calendar components value 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 interval can not be
related to each other or to a "VEVENT" scheduled. The
value BUSY-TENTATIVE indicates that the time interval is busy
because one or to more events have been tentatively scheduled for
that interval. If not specified on a "VTODO" calendar

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component, with property that allows this
parameter, the "RELATED-TO" property. default is BUSY.

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 parameter on Tuesday.\n
2. Telephone Conference: ABC Corp. sales representative called
to discuss new printer. Promised to get us a demo by Friday.\n
3. Henry Miller (Handsoff Insurance): Car was totaled by tree.
Is looking into a loaner car. 654-2323 (tel).
END:VJOURNAL

Figure 18

7.4. Free/Busy Component

Component FREEBUSY
property.

FREEBUSY;FBTYPE=BUSY:19980415T133000Z/19980415T170000Z

3.2.10. Language

Parameter Name: VFREEBUSY LANGUAGE

Purpose: Provide a grouping of component properties that describe
either a request To specify the language for free/busy time, describe a response to text values in a request
for free/busy time property or describe a published set of busy time.

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Formal
property parameter.

Format Definition: A "VFREEBUSY" calendar component The property parameter is defined by the following
notation:

freebusyc

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

fbprop "LANGUAGE" "=" language

language = *(

; the following are optional,
; but MUST NOT occur more than once

contact / dtstart / dtend / duration / dtstamp /
organizer / uid / url /

; the following are optional,
; and MAY occur more than once

attendee / comment / freebusy / rstatus / x-prop

)

Figure 19

Description: A "VFREEBUSY" calendar component is <Text identifying a grouping of
component language, as defined in [RFC1766]>

Description: This parameter can be specified on properties that represents either a request for, a reply to
a request for free or busy time information or with a published set
text value type. The parameter identifies the language of
busy time information.

When used to request free/busy time information, the "ATTENDEE"
property specifies the calendar users whose free/busy time is being
requested;
text in the "ORGANIZER" property specifies the calendar user who
is requesting the free/busy time; the "DTSTART" and "DTEND"
properties specify the window or property parameter value. The value of time for which
the free/busy time "language" property parameter is
being requested; the "UID" and "DTSTAMP" properties are specified to
assist that defined in [RFC1766].

For transport in proper sequencing of multiple free/busy time requests.

When used to reply to a request for free/busy time, the "ATTENDEE"
property specifies MIME entity, the calendar user responding Content-Language header field
can be used to set the free/busy time
request; the "ORGANIZER" property specifies the calendar user that
originally requested the free/busy time; the "FREEBUSY" property
specifies the free/busy time information (if it exists); and default language for the

"UID" and "DTSTAMP" properties are specified to assist in proper
sequencing 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 example makes use of multiple free/busy time replies.

When used to publish busy time, the "ORGANIZER" property specifies Quoted-Printable encoding

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the calendar user associated with the published busy time; the
"DTSTART" and "DTEND" properties June 2006

in order to represent non-ASCII characters.

LOCATION;LANGUAGE=3Dda:K=C3=B8benhavn

LOCATION;LANGUAGE=en:Copenhagen

3.2.11. Group or List Membership

Parameter Name: MEMBER

Purpose: To specify an inclusive time window
that surrounds the busy time information; the "FREEBUSY" property
specifies group or list membership of the published busy time information; and calendar user
specified by the "DTSTAMP" property.

Format Definition: The property specifies parameter is defined by the date/time that iCalendar object was created.

The "VFREEBUSY" calendar component cannot be nested within another
calendar component. Multiple "VFREEBUSY" calendar components following
notation:

memberparam = "MEMBER" "=" DQUOTE cal-address DQUOTE
*("," DQUOTE cal-address DQUOTE)

Description: This parameter can be specified within an iCalendar object. This permits on properties with a
CAL-ADDRESS value type. The parameter identifies the grouping of
Free/Busy information into logical collections, such as monthly groups of busy time information.

The "VFREEBUSY" calendar component is intended for use in iCalendar
object methods involving requests for free time, requests for busy
time, requests or
list membership for both free and busy, and the associated replies.

Free/Busy information is represented with calendar user specified by the "FREEBUSY" property.
This property provides
The parameter value either a terse representation of time periods. One
or more "FREEBUSY" properties can be specified single calendar address in the "VFREEBUSY" a quoted-
string or a COMMA character (US-ASCII decimal 44) list of calendar component.

When present
addresses, each in a "VFREEBUSY" quoted-string. The individual calendar component, the "DTSTART" and
"DTEND" properties SHOULD
address parameter values MUST each be specified prior to any "FREEBUSY"
properties. In a free time request, these properties can be used in
combination with the "DURATION" property to represent a request 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

3.2.12. Participation Status

Parameter Name: PARTSTAT

Purpose: To specify the participation status for a
duration of free time within a specified window of time.

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

Example 1:

Format Definition: The following is an example of a "VFREEBUSY" 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
END:VFREEBUSY

Figure 20

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Example 2: 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 information for
the next three months.
END:VFREEBUSY

Figure 21

Example 3: a "VFREEBUSY" calendar component used to publish 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

Figure 22

7.5. Time Zone Component

Component Name: VTIMEZONE

Purpose: Provide a grouping of component properties that defines a
time zone.

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

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

2*(

; 'tzid' is required, but MUST NOT occur more
; than once

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tzid June 2006

partstatparam = "PARTSTAT" "="
("NEEDS-ACTION" ; Event needs action
/ "ACCEPTED" ; 'last-mod' and 'tzurl' are optional,
but MUST NOT occur more than once

last-mod Event accepted
/ tzurl "DECLINED" ; Event declined
/ "TENTATIVE" ; one of 'standardc' or 'daylightc' MUST occur
..; and each MAY occur more than once.

standardc Event tentatively
; accepted
/ daylightc "DELEGATED" ; Event delegated
/ x-name ; Experimental status
/ iana-token) ; Other IANA registered
; status
; These are the following participation statuses for a "VEVENT". Default is optional,
; and MAY occur more than once

x-prop

)

"END" ":" "VTIMEZONE" CRLF

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

tzprop

"END" ":" "STANDARD" CRLF

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

tzprop

"END" ":" "DAYLIGHT" CRLF

tzprop = 3*( NEEDS-ACTION
partstatparam /= "PARTSTAT" "="
("NEEDS-ACTION" ; the following are each REQUIRED, To-do needs action
/ "ACCEPTED" ; but MUST NOT occur more than once

dtstart To-do accepted
/ tzoffsetto "DECLINED" ; To-do declined
/ tzoffsetfrom "TENTATIVE" ; To-do tentatively
; accepted
/ "DELEGATED" ; the following To-do delegated
/ "COMPLETED" ; To-do completed.
; COMPLETED property has
;date/time completed.
/ "IN-PROCESS" ; To-do in process of
; being completed
/ x-name ; Experimental status
/ iana-token) ; Other IANA registered
; status
; These are optional, the participation statuses for a "VTODO". Default is
; and MAY occur more than once

comment NEEDS-ACTION

partstatparam /= "PARTSTAT" "="
("NEEDS-ACTION" ; Journal needs action
/ rdate "ACCEPTED" ; Journal accepted
/ rrule "DECLINED" ; Journal declined
/ tzname x-name ; Experimental status
/ x-prop

)

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Figure 23

Description: A time zone is unambiguously defined by the set of time
measurement rules determined by iana-token) ; Other IANA registered
; status
; These are the governing body participation statuses for a given
geographic area. These rules describe at "VJOURNAL". Default is
; NEEDS-ACTION

Description: This parameter can be specified on properties with a minimum
CAL-ADDRESS value type. The parameter identifies the base offset
from UTC
participation status for the time zone, often referred to as calendar user specified by the Standard Time
offset. Many locations adjust their Standard Time forward
property value. The parameter values differ depending on whether
they are associated with a group scheduled "VEVENT", "VTODO" or
backward by
"VJOURNAL". The values MUST match one hour, in order to accommodate seasonal changes in
number of daylight hours, often referred to as Daylight Saving Time.
Some locations adjust their time by the values allowed for
the given calendar component. If not specified on a fraction of an hour. Standard
Time is also known as Winter Time. Daylight Saving Time property that
allows this parameter, the default value is also
known as Advanced Time, Summer Time, or Legal Time in certain
countries. NEEDS-ACTION.

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Example:

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

3.2.13. Recurrence Identifier Range

Parameter Name: RANGE

Purpose: To specify the effective range of recurrence instances from
the instance specified by the recurrence identifier specified by
the property.

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

rangeparam = "RANGE" "=" ("THISANDPRIOR"
; To specify all instances prior to the changes in time zone rules
in effect for New York City starting from 1967. Each line represents recurrence identifier
/ "THISANDFUTURE")
; To specify the instance specified by the recurrence identifier
; and all subsequent recurrence instances

Description: The parameter can be specified on a description or rule for property that
specifies a particular observance.

Effective Observance Rule

+-----------+-------------------------+--------+--------------+
| Date | (Date/Time) | Offset | Abbreviation |
+-----------+-------------------------+--------+--------------+
| 1967-* | last Sun 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 |
+-----------+-------------------------+--------+--------------+

Note: recurrence identifier. The specification parameter specifies the
effective range of a global time zone registry recurrence instances that is not
addressed specified by this document and the
property. The effective range is left for future study. However,
implementers may find from the Olson time zone database [TZ] a useful
reference. It recurrence identified
specified by the property. If this parameter is not specified an informal, public-domain collection of time zone
information, which
allowed property, then the default range is currently being maintained the single instance
specified by volunteer
Internet participants, and is used in several operating systems.
This database contains current and historical time zone information
for the recurrence identifier value of the property. The
parameter value can be "THISANDPRIOR" to indicate a wide variety range defined
by the recurrence identified value of locations around the globe; it provides property and all prior
instances. The parameter value can also be "THISANDFUTURE" to
indicate a time
zone range defined by the recurrence identifier for every unique time zone rule set in actual use
since 1970, and all
subsequent instances.

Example:

RECURRENCE-ID;RANGE=THISANDPRIOR:19980401T133000Z

3.2.14. Alarm Trigger Relationship

Parameter Name: RELATED

Purpose: To specify the relationship of the alarm trigger with historical data going back
respect to the introduction of
standard time.

Interoperability between two calendaring and scheduling applications,
especially for recurring events, to-dos start or journal entries, is end of the calendar component.

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dependent on the ability to capture and convey date and time
information in an unambiguous format. June 2006

Format Definition: The specification of current
time zone information property parameter is integral to this behavior.

If present, the "VTIMEZONE" calendar component defines defined by the set following
notation:

trigrelparam = "RELATED" "="
("START" ; Trigger off of
Standard Time and Daylight Saving Time observances (or rules) for a
particular time zone for a given interval start
/ "END") ; Trigger off of time. end

Description: The "VTIMEZONE"
calendar component cannot be nested within other calendar components.
Multiple "VTIMEZONE" calendar components parameter can exist in be specified on properties that
specify an iCalendar
object. In this situation, each "VTIMEZONE" MUST represent alarm trigger with a unique
time zone definition. This is necessary for some classes of events,
such as airline flights, that DURATION value type. The
parameter specifies whether the alarm will trigger relative to the
start in one time zone and or end in
another.

The "VTIMEZONE" of the calendar component MUST be present if component. The parameter value START
will set the iCalendar
object contains an RRULE that generates dates on both sides alarm to trigger off the start of a time
zone shift (e.g. both in Standard Time and Daylight Saving Time)
unless the iCalendar object intends calendar
component; the parameter value END will set the alarm to convey a floating time (See
Section 13.13 for proper interpretation trigger
off the end of floating time). It can be
present if the iCalendar object does calendar component. If the parameter is not contain such a RRULE. In
addition, if a RRULE
specified on an allowable property, then the default is present, there MUST be valid time zone
information for all recurrence instances.

The "VTIMEZONE" START.

Example:

TRIGGER;RELATED=END:PT5M

3.2.15. Relationship Type

Parameter Name: RELTYPE

Purpose: To specify the type of hierarchical relationship associated
with the calendar component MUST include specified by the "TZID" property.

Format Definition: The property
and at least one definition of parameter is defined by the following
notation:

reltypeparam = "RELTYPE" "="
("PARENT" ; Parent relationship. Default.
/ "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 standard or daylight component. property that
references another related calendar. The
standard or daylight component MUST include parameter specifies the
hierarchical relationship type of the "DTSTART",
"TZOFFSETFROM" and "TZOFFSETTO" properties.

An individual "VTIMEZONE" calendar component MUST be specified for
each unique "TZID"
referenced by the property. The parameter value specified in can be PARENT, to
indicate that the iCalendar object.

Each "VTIMEZONE" referenced calendar component consists of is a collection superior of one
or more sub-components
calendar component; CHILD to indicate that describe the rule for a particular
observance (either a Standard Time or a Daylight Saving Time
observance). The "STANDARD" sub-component consists of referenced calendar
component is a collection subordinate of properties the calendar component; SIBLING to
indicate that describe Standard Time. The "DAYLIGHT" sub- the referenced calendar component consists of is a collection of properties that describe
Daylight Saving Time. In general this collection peer of properties
consists of:

the first onset date-time for the observance

the last onset date-time for the observance, if a last onset
calendar component. If this parameter is
known.

the offset to be applied for the observance not specified on an

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a rule that describes June 2006

allowable property, the day and time when default relationship type is PARENT.

Example:

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

3.2.16. Participation Role

Parameter Name: ROLE

Purpose: To specify the observance takes
effect

an optional name participation role for the observance

For a given time zone, there may be multiple unique definitions calendar user
specified by the property.

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

roleparam = "ROLE" "="
("CHAIR" ; Indicates chair of the observances over
; calendar entity
/ "REQ-PARTICIPANT" ; Indicates a period of time. Each observance participant whose
; participation is described
using either required
/ "OPT-PARTICIPANT" ; Indicates a "STANDARD" or "DAYLIGHT" sub-component. The
collection of these sub-components participant whose
; participation is used to describe the time zone optional
/ "NON-PARTICIPANT" ; Indicates a participant who is
; copied for information
; purposes only
/ x-name ; Experimental role
/ iana-token) ; Other IANA role
; Default is REQ-PARTICIPANT

Description: This parameter can be specified on properties with a given period of time.
CAL-ADDRESS value type. The offset to apply at any given time is
found by locating parameter specifies the observance that has participation
role for the last onset date and
time before calendar user specified by the time property in question, and using the offset value from
that observance.

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

The mandatory "TZID" 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

3.2.17. RSVP Expectation

Parameter Name: RSVP

Purpose: To specify whether there is an expectation of a text value that uniquely
identifies favor of a
reply from the VTIMZONE calendar component within user specified by the scope of an property value.

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Format Definition: The optional "LAST-MODIFIED" property parameter is defined by the following
notation:

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

Description: This parameter can be specified on properties with a UTC
CAL-ADDRESS value that specifies
the date and time that this time zone definition was last updated. type. The optional "TZURL" parameter identifies the expectation
of a reply from the calendar user specified by the property value.
This parameter is url value that points used by the "Organizer" to request a published
VTIMEZONE definition. TZURL SHOULD refer to
participation status reply from an "Attendee" of a resource group scheduled
event or to-do. If not specified on a property that allows this
parameter, the default value is
accessible by anyone who might need to interpret FALSE.

Example:

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

3.2.18. Sent By

Parameter Name: SENT-BY

Purpose: To specify the object. This
SHOULD NOT normally be a file: URL or other URL calendar user that is not widely-
accessible.

The collection acting on behalf of properties that are used to define the STANDARD and
DAYLIGHT sub-components include:
calendar user specified by the property.

Format Definition: The mandatory "DTSTART" property gives the effective onset date and
local time for parameter is defined by the time zone sub-component definition. "DTSTART" in
this usage MUST following
notation:

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

Description: This parameter can be specified as on properties with a local DATE-TIME value.
CAL-ADDRESS value type. The mandatory "TZOFFSETFROM" property gives parameter specifies the UTC offset which calendar user
that is
in use when the onset acting on behalf of this time zone observance begins.
"TZOFFSETFROM" is combined with "DTSTART" to define the effective
onset for the time zone sub-component definition. For example, the
following represents the time at which calendar user specified by the observance of Standard
Time took effect
property. The parameter value MUST be a MAILTO URI as defined in Fall 1967 for New York City:

DTSTART:19671029T020000

TZOFFSETFROM:-0400

Figure 24
[RFC1738]. The individual calendar address parameter values MUST
each be specified in a quoted-string.

Example:

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

3.2.19. Time Zone Identifier

Parameter Name: TZID

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The mandatory "TZOFFSETTO " property gives June 2006

Purpose: To specify the UTC offset identifier for the time zone sub-component (Standard Time or Daylight Saving Time) when
this observance is in use.

The optional "TZNAME" property is the customary name for the time
zone. It may be specified multiple times, to allow definition for specifying
multiple language variants of the a
time zone names. This could be
used for displaying dates.

If specified, the onset for the observance defined by component in the time zone
sub-component property value.

Format Definition: The property parameter is defined by either the "RRULE" or "RDATE" property.
If neither is specified, only one sub-component can following
notation:

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

tzidprefix = "/"

Description: The parameter MUST be specified in on the "VTIMEZONE" calendar component "DTSTART",
"DTEND", "DUE", "EXDATE" and it "RDATE" properties when either a
DATE- TIME or TIME value type is assumed that the single
observance specified is always in effect.

The "RRULE" property defines the recurrence rule for the onset of the
observance defined by this time zone sub-component. Some specific
requirements for and when the usage of RRULE for this purpose include:

If observance value is known to have an effective end date, the "UNTIL"
recurrence rule parameter MUST be used
not either a UTC or a "floating" time. Refer to specify the last valid
onset DATE-TIME or
TIME value type definition for a description of this observance (i.e., the UNTIL date-time will be equal
to the last instance generated by the recurrence pattern). It
MUST be specified in UTC time.

The "DTSTART" and "floating
time" formats. This property parameter specifies a text value
which uniquely identifies the "TZOFFSETTO" properties MUST "VTIMEZONE" calendar component to be
used when
generating evaluating the onset date-time values (instances) from time portion of the RRULE.

Alternatively, property. The value
of the "RDATE" TZID property can parameter will be used equal to define the onset value of the observance by giving
TZID property for the matching time zone definition. An
individual onset date and times.
"RDATE" "VTIMEZONE" calendar component MUST be specified for
each unique "TZID" parameter value specified in this usage the iCalendar
object.

The parameter MUST be specified as on properties with a local DATE-TIME
value in if the DATE-TIME is not either a UTC or a "floating" time.

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

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

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Example 1: Time zone information for the Eastern United States using
"RDATE" property. Note SOLIDUS character (US-ASCII decimal 47) as a
prefix, indicates that this TZID represents a unique ID in a
globally defined time zone registry (when such registry is only suitable for
defined).

Note: This document does not define 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 naming convention for EST
time zone identifiers. Implementers may want to use the naming
conventions defined in existing time zone specifications such
as the public-domain Olson database [TZDB]. The specification
of globally unique time zone identifiers is not addressed by
this scenario). For example, document and is left for future study.

The following are examples of this can property parameter:

DTSTART;TZID=US-Eastern:19980119T020000

DTEND;TZID=US-Eastern:19980119T030000

The TZID property parameter MUST NOT be used for a
recurring event that occurs every Friday, 8am-9:00 AM, starting June
1, 1997, ending December 31, 1997.

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

Figure 25 applied to DATE-TIME or

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Example 2: Current June 2006

TIME properties whose time zone rules for the Eastern United States
using values are specified in UTC.

The use of local time in a RRULE recurrence pattern. Note that there DATE-TIME or TIME value without the
TZID property parameter is no effective
end date to either of the Standard Time or Daylight Time rules. This
information would be valid for interpreted as a recurring event starting today and
continuing indefinitely.

BEGIN:VTIMEZONE
TZID:US-Eastern
LAST-MODIFIED:19870101T000000Z
TZURL:http://zones.stds_r_us.net/tz/US-Eastern
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

Figure 26

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Example 3: A fictitious set local time
value, regardless of rules for the 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:US- -Fictitious-Eastern
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

Figure 27

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Example 4: A fictitious set existence of rules for "VTIMEZONE" calendar
components in the Eastern United States,
where iCalendar object.

For more information see the first Daylight Time rule has an effective end date. There
is a second Daylight Time rule that picks up where sections on the other left
off.

Figure 28

7.6. Alarm Component

Component data types DATE-TIME
and TIME.

3.2.20. Value Data Types

Parameter Name: VALARM VALUE

Purpose: Provide To explicitly specify the data type format for a grouping of component properties that define an
alarm.

Formal property
value.

Format Definition: A "VALARM" calendar component The property parameter is defined by the following
notation:

alarmc

valuetypeparam = "BEGIN" ":" "VALARM" CRLF
(audioprop "VALUE" "=" valuetype

valuetype = ("BINARY"
/ dispprop "BOOLEAN"
/ emailprop "CAL-ADDRESS"
/ procprop)
"END" ":" "VALARM" CRLF

audioprop = 2*(

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; 'action' and 'trigger' are both REQUIRED,
; but MUST NOT occur more than once

action "DATE"
/ trigger "DATE-TIME"
/

; 'duration' and 'repeat' are both optional,
; and MUST NOT occur more than once each,
; but if one occurs, so MUST the other

duration "DURATION"
/ repeat "FLOAT"
/

; the following is optional,
; but MUST NOT occur more than once

attach "INTEGER"
/

; the following is optional,
; and MAY occur more than once

x-prop

)

dispprop = 3*(

; the following are all REQUIRED,
; but MUST NOT occur more than once

action / description / trigger "PERIOD"
/

; 'duration' and 'repeat' are both optional,
; and MUST NOT occur more than once each,
; but if one occurs, so MUST the other

duration "RECUR"
/ repeat "TEXT"
/

; the following is optional,

; and MAY occur more than once

*x-prop

)

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emailprop = 5*(

; the following are all REQUIRED,
; but MUST NOT occur more than once

action "TIME"
/ description "URI"
/ trigger "UTC-OFFSET"
/ summary

; the following is REQUIRED, x-name
; and MAY occur more than once

attendee Some experimental iCalendar data type.
/ iana-token)
; 'duration' and 'repeat' are both optional,
; and MUST NOT occur more than once each,
; but if one occurs, so MUST the Some other

duration / repeat /

; the following are optional,
; and MAY occur more than once

attach / x-prop

)

procprop = 3*(

; IANA registered iCalendar data type.

Description: The parameter specifies the following are all REQUIRED,
; but MUST NOT occur more than once

action / attach / trigger /

; 'duration' and 'repeat' are both optional,
; data type and MUST NOT occur more than once each,
; but if one occurs, so MUST format of the other

duration / repeat /

; 'description' is optional,
; and
property value. The property values MUST NOT occur more than once

description /

; the following is optional,
; be of a single value
type. For example, a "RDATE" property cannot have a combination
of DATE- TIME and MAY occur more than once TIME value types.

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x-prop

)

Figure 29

Description: A "VALARM" calendar component June 2006

If the property's value is a grouping of component
properties that the default value type, then this
parameter need not be specified. However, if the property's
default value type is a reminder or alarm for an event or a to-do. For
example, it may overridden by some other allowable value
type, then this parameter MUST be used to define a reminder for a pending event or
an overdue to-do. specified.

3.3. Property Value Data Types

The "VALARM" calendar component MUST include the "ACTION" and
"TRIGGER" properties. properties in an iCalendar object are strongly typed. The "ACTION"
definition of each property further constrains restricts the
"VALARM" calendar component value to be one of the
value data types, or simply value types, defined in this section.
The value type for a property will either be specified implicitly as
the following ways:

When default value type or will be explicitly specified with the action is "AUDIO",
"VALUE" parameter. If the alarm can also include one and only
one "ATTACH" property, which MUST point to value type of a sound resource, which is
rendered when the alarm is triggered.

When the action property is "DISPLAY", one of the alarm
alternate valid types, then it MUST also include a
"DESCRIPTION" property, which contains the text to be displayed when explicitly specified with the alarm
"VALUE" parameter.

3.3.1. Binary

Value Name: BINARY

Purpose: This value type is triggered.

When the action is "EMAIL", the alarm MUST include a "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 one or more "ATTENDEE" properties, which identify properties that contain the
email address
a character encoding of attendees to receive inline binary data. For example, an
inline attachment of an object code might be included in an
iCalendar object.

Format Definition: The value type is defined by the message. It can following
notation:

binary = *(4b-char) [b-end]
; A "BASE64" encoded character string, as defined by [RFC2045].

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

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

Description: Property values with this value type MUST also include one or more "ATTACH" properties, which are intended to
the inline encoding parameter sequence of ";ENCODING=BASE64".
That is, all inline binary data MUST first be
sent as message attachments. When character encoded
using the alarm "BASE64" encoding method defined in [RFC2045]. No
additional content value encoding (i.e., BACKSLASH character
encoding) is triggered, the email
message defined for this value type.

Example: The following is sent.

When the action an abridged example of a "BASE64" encoded
binary value data.

ATTACH;VALUE=BINARY;ENCODING=BASE64:MIICajCCAdOgAwIBAgICBEUwDQY
JKoZIhvcNAQEEBQAwdzELMAkGA1UEBhMCVVMxLDAqBgNVBAoTI05ldHNjYXBlI
ENvbW11bmljYXRpb25zIENvcnBvcmF0aW9uMRwwGgYDVQQLExNJbmZv

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<...remainder of "BASE64" encoded binary data...>

3.3.2. Boolean

Value Name: BOOLEAN

Purpose: This value type is "PROCEDURE", the alarm MUST include one and only
one "ATTACH" property, which MUST point used to identify properties that contain
either a procedure resource,
which "TRUE" or "FALSE" Boolean value.

Format Definition: The value type is invoked when defined by the alarm following
notation:

boolean = "TRUE" / "FALSE"

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

Example: The "VALARM" calendar component MUST only appear within either following is an example of a
"VEVENT" or "VTODO" calendar component. "VALARM" calendar components
cannot be nested. Multiple mutually independent "VALARM" calendar
components can be specified for hypothetical property that
has a BOOLEAN value type:

GIBBERISH:TRUE

3.3.3. Calendar User Address

Value Name: CAL-ADDRESS

Purpose: This value type is used to identify properties that contain
a single "VEVENT" or "VTODO" calendar
component. user address.

Format Definition: The "TRIGGER" property specifies when value type is defined by the alarm will be triggered. following
notation:

cal-address = uri

Description: The "TRIGGER" property specifies value is a duration prior to the start of an
event URI as defined by [RFC1738] or any other
IANA registered form for a to-do. The "TRIGGER" edge may be explicitly set to be
relative URI. When used to address an Internet
email transport address for a calendar user, the "START" or "END" of the event or to-do with the
"RELATED" parameter of the "TRIGGER" property. The "TRIGGER"
property value type can alternatively MUST be set to an absolute calendar a
MAILTO URI, as defined by [RFC1738]. No additional content value
encoding (i.e., BACKSLASH character encoding) is defined for this
value type.

Example:

ATTENDEE:MAILTO:jane_doe@host.com

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date and time of day value.

In an alarm set June 2006

3.3.4. Date

Value Name: DATE

Purpose: This value type is used to trigger on the "START" of an event or to-do, the
"DTSTART" property MUST be present in the associated event or to-do.
In an alarm in identify values that contain a "VEVENT"
calendar component set to trigger date.

Format 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
"END" property permits, multiple "date" values are
specified as a COMMA character (US-ASCII decimal 44) separated
list of values. The format for the event, either the "DTEND" property MUST be present, or value type is expressed as the "DTSTART" and "DURATION" properties MUST both be present. In an
alarm in
[ISO.8601.1988] complete representation, basic format for a "VTODO"
calendar component set to trigger on the "END" date. The textual format specifies a four-digit year,
two-digit month, and two-digit day of the to-do, either the "DUE" property MUST be present, or month. There are no
separator characters between the
"DTSTART" year, month and "DURATION" properties MUST both be present.

The alarm can be day component
text.

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

Example: The following represents July 14, 1997:

19970714

3.3.5. Date-Time

Value Name: DATE-TIME

Purpose: This value type is used to identify values that it triggers repeatedly. A
definition of an alarm with specify a repeating trigger MUST include both the
"DURATION"
precise calendar date and "REPEAT" properties. time of day.

Format Definition: The "DURATION" property
specifies value type is defined by the delay period, after which following
notation:

date-time = date "T" time ;As specified in the alarm will repeat. The
"REPEAT" property specifies date and time
;value definitions

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Description: If the number property permits, multiple "date-time" values are
specified as a COMMA character (US-ASCII decimal 44) separated
list of values. No additional repetitions that
the alarm will triggered. This repitition count content value encoding (i.e.,
BACKSLASH character encoding) is in addition to
the initial triggering of the alarm. Both of these properties MUST
be present in order defined for this value type.

The "DATE-TIME" data type is used to specify identify values that contain
a repeating alarm. If one precise calendar date and time of these
two properties day. The format is absent, then the alarm will not repeat beyond based on
the
initial trigger. [ISO.8601.1988] complete representation, basic format for a
calendar date and time of day. The "ACTION" property text format is used within a concatenation
of the "VALARM" calendar component
to specify "date", followed by the LATIN CAPITAL LETTER T character
(US-ASCII decimal 84) time designator, followed by the "time"
format.

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

The form of action invoked when date and time with UTC offset MUST NOT be used. For
example, the alarm following is triggered.
The "VALARM" properties provide enough information not valid for a specific
action to be invoked. It date-time value:

DTSTART:19980119T230000-0800 ;Invalid time format

FORM #1: DATE WITH LOCAL TIME

The date with local time form is typically the responsibility of simply a
"Calendar User Agent" (CUA) to deliver the alarm in the specified
fashion. An "ACTION" property date-time value of AUDIO specifies an alarm that
causes a sound to be played to alert
does not contain the user; DISPLAY specifies an
alarm that causes UTC designator nor does it reference a text message time
zone. For example, the following represents Janurary 18, 1998, at
11 PM:

DTSTART:19980118T230000

Date-time values of this type are said to be displayed "floating" and are
not bound to any time zone in particular. They are used to
represent the user; EMAIL
specifies same hour, minute, and second value regardless of
which time zone is currently being observed. For example, an alarm
event can be defined that indicates that causes an electronic email message to individual will be
delivered
busy from 11:00 AM to one or more email addresses; and PROCEDURE specifies an
alarm that causes 1:00 PM every day, no matter which time zone
the person is in. In these cases, a procedure to local time can be executed. specified.
The "ACTION" property
MUST specify one and only one recipient of these values.

In an AUDIO alarm, if the optional "ATTACH" iCalendar object with a property is included, it
MUST specify an audio sound resource. The intention is that value
consisting of a local time, without any relative time zone
information, SHOULD interpret the
sound will be played value as the alarm effect. If an "ATTACH" property is
specified that does not refer being fixed to a sound resource, or if whatever
time zone the
specified sound resource cannot be rendered (because its format ATTENDEE is
unsupported, or because it cannot be retrieved), then the CUA or
other entity responsible for playing in at any given moment. This means that
two ATTENDEEs, in different time zones, receiving the sound may choose a fallback
action, such same event
definition as playing a built-in default sound, or playing no sound
at all.

In a DISPLAY alarm, the intended alarm effect is for the text value
of floating time, may be participating in the "DESCRIPTION" property to event
at different actual times. Floating time SHOULD only be displayed to used
where that is the user. reasonable behavior.

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In an EMAIL alarm, the intended alarm effect most cases, a fixed time is for an email message
to be composed and delivered to all the addresses specified by the
"ATTENDEE" properties desired. To properly communicate a
fixed time in the "VALARM" calendar component. The
"DESCRIPTION" a property of the "VALARM" calendar component value, either UTC time or local time with
time zone reference MUST be
used as the body text specified.

The use of the message, and the "SUMMARY" property MUST
be used as the subject text. Any "ATTACH" properties local time in the "VALARM"
calendar component SHOULD be sent as attachments to the message.

In a PROCEDURE alarm, DATE-TIME value without the "ATTACH" TZID
property in the "VALARM" calendar
component MUST specify a procedure or program that parameter is intended to be
invoked interpreted as floating time,
regardless of the alarm effect. If existence of "VTIMEZONE" calendar components in
the procedure iCalendar object.

FORM #2: DATE WITH UTC TIME

The date with UTC time, or program absolute time, is in identified by a
format that cannot be rendered, then no procedure alarm will be
invoked. If the "DESCRIPTION" property is present, its value
specifies LATIN
CAPITAL LETTER Z suffix character (US-ASCII decimal 90), the argument string UTC
designator, appended to the time value. For example, the
following represents January 19, 1998, at 0700 UTC:

DTSTART:19980119T070000Z

The TZID property parameter MUST NOT be passed applied to the procedure or
program. "Calendar User Agents" that receive an iCalendar object 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 this category of alarm, can disable or allow the "Calendar User" reference to disable, or otherwise ignore this type of alarm. While a very
useful alarm capability, the PROCEDURE type of alarm SHOULD be
treated time zone information is
identified by the "Calendar User Agent" as a potential security risk.

Example 1: A "VALARM" calendar 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;FMTTYPE=audio/basic:ftp://host.com/pub/sounds/bell-01.aud
END:VALARM

Figure 30

Example 2: A "VALARM" calendar component that specifies a display
alarm that will trigger 30 minutes before use the scheduled start of TZID property parameter to reference the
event or
appropriate time zone definition. TZID is discussed in detail in
the due date/time of section on Time Zone. For example, the to-do it is associated with and
will repeat following represents 2 more times at 15 minute intervals:

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

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DTSTART;TZID=US-Eastern:19980119T020000

Example: The following represents July 14, 2006 [Page 43]

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Figure 31

Example 3: A "VALARM" calendar component that specifies an email
alarm that will trigger 2 days before the scheduled due date/time 1997, at 1:30 PM in New
York City in each of
a to-do it is associated with. It does not repeat. The email has a
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 attendees
to three time formats, using the weekly managers meeting (MGR-LIST). Attached is a
pointer "DTSTART"
property.

DTSTART:19970714T133000 ;Local time
DTSTART:19970714T173000Z ;UTC time
DTSTART;TZID=US-Eastern:19970714T133000 ;Local time and time
; zone reference

A time value MUST ONLY specify 60 seconds when specifying the document template for
periodic "leap second" in the agenda file.
ATTACH;FMTTYPE=application/msword:http://host.com/templates/agen
da.doc
END:VALARM

Figure 32

Example 4: 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 procedure
file.

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

Figure 33 time value. For example:

COMPLETED:19970630T235960Z

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8. Properties

A property June 2006

3.3.6. Duration

Value Name: DURATION

Purpose: This value type is the definition of an individual attribute describing a
calendar or used to identify properties that contain
a calendar component. A property takes the form duration of time.

Format Definition: The value type is defined by the "contentline" notation defined in section 4.1.1.

The following is an example of a property:

DTSTART:19960415T133000Z

This memo imposes no ordering of 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=US-Eastern:19980714T120000 is the
same as DtStart;TzID=US-Eastern:19980714T120000.

8.1. Calendar Properties

The Calendar Properties are attributes that apply to the iCalendar
object, as a whole. These properties do not appear within a calendar
component. They SHOULD be specified after
notation:

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 the "BEGIN:VCALENDAR"
property and prior to any calendar component.

8.1.1. Calendar Scale

Property Name: CALSCALE

Purpose: This property defines permits, multiple "duration" values are
specified by a COMMA character (US-ASCII decimal 44) separated
list of values. The format is expressed as the calendar scale used [ISO.8601.1988]
basic format for the
calendar information specified in the iCalendar object.

Value Type: TEXT

do Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: Property duration of time. The format can be specified represent
durations in an iCalendar object. The
default terms of weeks, days, hours, minutes, and seconds.

No additional content value is "GREGORIAN".

Description: encoding (i.e., BACKSLASH character
encoding) are defined for this value type.

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

P15DT5H0M20S

A duration of 7 weeks would be:

P7W

3.3.7. Float

Value Name: FLOAT

Purpose: This memo value type is based on the Gregorian calendar scale. used to identify properties that contain
a real number value.

Format Definition: The
Gregorian calendar scale is assumed if this property is not specified
in the iCalendar object. It value type is expected that other calendar scales
will be defined in other specifications or by future versions of this
memo. the following
notation:

float = (["+"] / "-") 1*DIGIT ["." 1*DIGIT]

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Description: If the property permits, multiple "float" values are
specified by a COMMA character (US-ASCII decimal 44) separated
list of values.

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

Example:

1000000.0000001
1.333
-3.14

3.3.8. Integer

Value Name: INTEGER

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

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

calscale = "CALSCALE" calparam ":" calvalue CRLF

calparam = *(";" xparam)

calvalue

integer = "GREGORIAN" (["+"] / iana-token

Figure 35

Example: The following is an example of this property:

CALSCALE:GREGORIAN

Figure 36

8.1.2. Method

Property Name: METHOD

Purpose: This property defines the iCalendar object method associated
with "-") 1*DIGIT

Description: If the calendar object.

Value Type: TEXT

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: The property can be permits, multiple "integer" values are
specified in an iCalendar object.

Description: When used in by a MIME message entity, the value COMMA character (US-ASCII decimal 44) separated
list of this
property MUST be the same as the Content-Type "method" parameter
value. This property can only appear once within the iCalendar
object. values. The valid range for "integer" is -2147483648 to
2147483647. If either the "METHOD" property or the Content-Type "method"
parameter sign is not specified, then the other MUST also value is
assumed to be specified. positive.

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

Example:

1234567890
-1234567890
+1234567890
432109876

3.3.9. Period of conveying a scheduling
semantic. Time

Value Name: PERIOD

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

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

method = "METHOD" metparam ":" metvalue CRLF

metparam

period = *(";" xparam)

metvalue period-explicit / period-start

period-explicit = iana-token

Example: date-time "/" date-time
; [ISO.8601.1988] complete representation basic format for a
; period of time consisting of a start and end. The following is start MUST
; be before the end.

period-start = date-time "/" dur-value
; [ISO.8601.1988] complete representation basic format for a hypothetical example
; period of this property to
convey that time consisting of a start and positive duration
; of time.

Description: If the iCalendar object is property permits, multiple "period" values are
specified by a request for COMMA character (US-ASCII decimal 44) separated
list of values. There are two forms of a meeting:

METHOD:REQUEST

Figure 38

8.1.3. Product Identifier

Property Name: PRODID

Purpose: period of time. First,
a period of time is identified by its start and its end. This property specifies
format is expressed as the identifier [ISO.8601.1988] complete
representation, basic format for "DATE-TIME" start of the product that
created period,
followed by a SOLIDUS character (US-ASCII decimal 47), followed by
the iCalendar object.

Value Type: TEXT

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: "DATE-TIME" of the end of the period. The property start of the period
MUST be specified once in an iCalendar
object.

Description: The vendor before the end of the implementation SHOULD assure that this
is period. Second, a globally unique identifier; using some technique such as an FPI
value, as defined in [ISO 9070].

This property SHOULD not period of time
can also be used to alter defined by a start and a positive duration of time.
The format is expressed as the interpretation [ISO.8601.1988] complete
representation, basic format for the "DATE-TIME" start of an
iCalendar object beyond the semantics specified in this memo. For
example, it is not to be used to further
period, followed by a SOLIDUS character (US-ASCII decimal 47),
followed by the understanding [ISO.8601.1988] basic format for "DURATION" of non-
standard properties. 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 value encoding (i.e., BACKSLASH character
encoding) is defined for this value type.

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3.3.10. Recurrence Rule

Value Name: RECUR

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

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

prodid = "PRODID" pidparam ":" pidvalue CRLF
pidparam = *(";" xparam)

pidvalue

recur = text
;Any text that describes the product and version
;and that is generally assured of being unique.

Figure 39

Example: The following is an example of this property. It does not
imply that English is the default language.

PRODID:-//ABC Corporation//NONSGML My Product//EN

Figure 40

8.1.4. Version

Property Name: VERSION

Purpose: This property specifies the identifier corresponding to the
highest version number "FREQ"=freq *(

; either UNTIL or the minimum COUNT may appear in a 'recur',
; but UNTIL and maximum range of the
iCalendar specification that is required COUNT MUST NOT occur in order to interpret the
iCalendar object.

Value Type: TEXT

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This property MUST be specified by an iCalendar object, same 'recur'

( ";" "UNTIL" "=" enddate ) /
( ";" "COUNT" "=" 1*DIGIT ) /

; the rest of these keywords are optional,
; but MUST only be specified once.

Description: A NOT occur more than once

( ";" "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 )
)

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

enddate = date
enddate =/ date-time ;An UTC value of "2.0" corresponds

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

seconds = 1DIGIT / 2DIGIT ;0 to this memo. 59

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

minutes = 1DIGIT / 2DIGIT ;0 to 59

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

version June 2006

byhrlist = "VERSION" verparam ":" vervalue CRLF

verparam hour / ( hour *("," hour) )

hour = *(";" xparam)

vervalue 1DIGIT / 2DIGIT ;0 to 23

bywdaylist = "2.0" ;This memo weekdaynum / maxver ( weekdaynum *("," weekdaynum) )

weekdaynum = [([plus] ordwk / (minver ";" maxver)

minver minus ordwk)] weekday

plus = [A IANA registered iCalendar version identifier]
;Minimum iCalendar version needed "+"

minus = "-"

ordwk = 1DIGIT / 2DIGIT ;1 to parse the iCalendar object

maxver 53

weekday = [A IANA registered iCalendar version identifier]
;Maximum iCalendar version needed "SU" / "MO" / "TU" / "WE" / "TH" / "FR" / "SA"
;Corresponding to parse the iCalendar object

Example: The following is an example SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY,
;FRIDAY, SATURDAY and SUNDAY days of this property:

VERSION:2.0

8.2. Descriptive Component Properties

The following properties can appear within calendar components, as
specified by each component property definition. These specify
descriptive information about calendar components.

8.2.1. Attachment

Property Name: ATTACH

Purpose: The property provides the capability to associate a document
object with a calendar component.

Value Type: The default value type for this property is URI. The
value type can also be set to BINARY week.

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

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

ordmoday = 1DIGIT / 2DIGIT ;1 to indicate inline binary
encoded content information.

Property Parameters: Non-standard, inline encoding, format type and
value data type property parameters can be specified on this
property.

Conformance: The property can be specified in a "VEVENT", "VTODO",
"VJOURNAL" or "VALARM" calendar components.

Description: The property can be specified within "VEVENT", "VTODO",
"VJOURNAL", or "VALARM" calendar components. This property can be
specified multiple times within an iCalendar object.

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

attach 31

byyrdaylist = "ATTACH" attparam ":" uri CRLF

attach =/ "ATTACH" attparam ";" "ENCODING" "=" "BASE64"
";" "VALUE" "=" "BINARY" ":" binary

attparam yeardaynum / ( yeardaynum *("," yeardaynum) )

yeardaynum = *(

; the following is optional,
; but MUST NOT occur more than once

(";" fmttypeparam) ([plus] ordyrday) /

; the following is optional,
; and MAY occur more than once

(";" xparam) (minus ordyrday)

ordyrday = 1DIGIT / 2DIGIT / 3DIGIT ;1 to 366

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

Example: The following are examples of this property:

ATTACH:CID:jsmith.part3.960817T083000.xyzMail@host1.com

ATTACH;FMTTYPE=application/postscript:ftp://xyzCorp.com/pub/
reports/r-960812.ps

8.2.2. Categories

Property Name: CATEGORIES

Purpose: This property defines

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

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

monthnum = 1DIGIT / 2DIGIT ;1 to 12

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

setposday = yeardaynum

Description: If the categories for a calendar
component.

Value Type: TEXT

Property Parameters: Non-standard and language property parameters
can be specified on this property.

Conformance: The property can be permits, multiple "recur" values are
specified within "VEVENT", "VTODO"
or "VJOURNAL" calendar components.

Description: This property is used to specify categories or subtypes by a COMMA character (US-ASCII decimal 44) separated
list of the calendar component. values. The categories are useful in searching
for value type is a calendar component structured value consisting
of a particular type and category. Within
the "VEVENT", "VTODO" list of one or "VJOURNAL" calendar components, more than
one category can be specified as recurrence grammar parts. Each rule part
is defined by a list of categories NAME=VALUE pair. The rule parts are separated
from each other by the SEMICOLON character (US-ASCII decimal 59).

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the COMMA character (US-ASCII decimal 44).

categories = "CATEGORIES" catparam ":" text *("," text)
CRLF

catparam = *(

; the following is optional,
; but MUST NOT occur more than once

(";" languageparam ) /

; the following is optional,
; and MAY occur more than once

(";" xparam)

) June 2006

The following rule parts are examples of categories.

CATEGORIES:APPOINTMENT,EDUCATION

CATEGORIES:MEETING

8.2.3. Classification

Property Name: CLASS

Purpose: This property defines the access classification for a
calendar component.

Value Type: TEXT

Property Parameters: Non-standard property parameters can not ordered in any particular sequence.
Individual rule parts MUST only be specified on this property.

Conformance: once.

The property can FREQ rule part identifies the type of recurrence rule. This
rule part MUST be specified once in the recurrence rule. Valid values
include SECONDLY, to specify repeating events based on an interval
of a "VEVENT",
"VTODO" second or "VJOURNAL" calendar components.

Description: An access classification is only one component more; MINUTELY, to specify repeating events based
on an interval of the
general security system within a calendar application. It provides a
method of capturing the scope of the access the calendar owner
intends for information within minute or more; HOURLY, to specify repeating
events based on an individual calendar entry. The
access classification interval of an individual iCalendar component is useful
when measured along with the other security components hour or more; DAILY, to specify
repeating events based on an interval of a calendar
system (e.g., calendar user authentication, authorization, access
rights, access role, etc.). Hence, the semantics day or more; WEEKLY, to
specify repeating events based on an interval of the individual

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access classifications cannot be completely defined by this memo
alone. Additionally, due a week or more;
MONTHLY, to the "blind" nature specify repeating events based on an interval of most exchange
processes using this memo, these access classifications cannot serve
as a
month or more; and YEARLY, to specify repeating events based on an enforcement statement
interval of a year or more.

The INTERVAL rule part contains a positive integer representing
how often the recurrence rule repeats. The default value is "1",
meaning every second for a system receiving SECONDLY rule, or every minute for a
MINUTELY rule, every hour for an iCalendar
object. Rather, they provide HOURLY rule, every day for a method
DAILY rule, every week for capturing the intention of
the calendar owner a WEEKLY rule, every month for a
MONTHLY rule and every year for a YEARLY rule.

The UNTIL rule part defines a date-time value which bounds the access to
recurrence rule in an inclusive manner. If the calendar component.

Formal Definition: The property is defined value specified 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
UNTIL is an example of this property:

CLASS:PUBLIC

8.2.4. Comment

Property Name: COMMENT

Purpose: This property specifies non-processing information intended
to provide a comment to synchronized with the calendar user.

Value Type: TEXT

Property Parameters: Non-standard, alternate text representation and
language property parameters can be specified on recurrence, this property.

Conformance: This property can be specified in "VEVENT", "VTODO",
"VJOURNAL", "VTIMEZONE" date or "VFREEBUSY" calendar components.

Description: The property can be specified multiple times.

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Formal Definition: The property is defined by
date-time becomes the following notation:

comment = "COMMENT" commparam ":" text CRLF

commparam = *(

; last instance of the following are optional,
; but recurrence. If
specified as a date-time value, then it MUST NOT occur more than once

(";" altrepparam) / (";" languageparam) /

; be specified in an
UTC time format. If not present, and the following COUNT rule part is optional,
; and MAY occur more than once

(";" xparam)

)

Example: The following also
not present, the RRULE is an example of this property:

COMMENT:The meeting really needs considered to include both ourselves
and repeat forever.

The COUNT rule part defines the customer. We can't hold this meeting without them.
As a matter number of fact\, occurrences at which to
range-bound the venue for recurrence. The "DTSTART" property value, if
specified, counts as the meeting ought to be at
their site. - - John

8.2.5. Description

Property Name: DESCRIPTION

Purpose: This property provides first occurrence.

The BYSECOND rule part specifies a more complete description COMMA character (US-ASCII
decimal 44) separated list of the
calendar component, than that provided by the "SUMMARY" property.

Value Type: TEXT

Property Parameters: Non-standard, alternate text representation and
language property parameters can be specified on this property.

Conformance: The property can be specified in the "VEVENT", "VTODO",
"VJOURNAL" or "VALARM" calendar components. The property can be
specified multiple times only seconds within a "VJOURNAL" calendar component.

Description: This property is used in the "VEVENT" and "VTODO" minute. Valid
values are 0 to
capture lengthy textual decriptions associated with the activity.

This property is used in the "VJOURNAL" calendar component 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 capture
one more textual journal entries.

This property is used in 59. The BYHOUR rule part
specifies a COMMA character (US- ASCII decimal 44) separated list
of hours of the "VALARM" calendar component day. Valid values are 0 to capture 23.

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

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the display text for June 2006

Each BYDAY value can also be preceded by a DISPLAY category of alarm, to capture positive (+n) or
negative (-n) integer. If present, this indicates the body
text for an EMAIL category nth
occurrence of alarm and to capture the argument
string for specific day within the MONTHLY or YEARLY RRULE.
For example, within a PROCEDURE category of alarm.

Formal Definition: The property is defined by MONTHLY rule, +1MO (or simply 1MO)
represents the following notation:

description = "DESCRIPTION" descparam ":" text CRLF

descparam = *(

; first Monday within the following are optional,
; but MUST NOT occur more than once

(";" altrepparam) / (";" languageparam) /

; month, whereas -1MO
represents the following is optional,
; and MAY occur more than once

(";" xparam)

)

Example: The following is an example last Monday 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.

The following is month. If an example integer modifier
is not present, it means all days of this type within the property with folding
specified frequency. For example, within a MONTHLY rule, MO
represents all Mondays within the month.

The BYMONTHDAY rule part specifies a COMMA character (ASCII
decimal 44) separated list of long
lines:

DESCRIPTION:Last draft days of the new novel is month. Valid values are
1 to be completed
for 31 or -31 to -1. For example, -10 represents the editor's proof today.

8.2.6. Geographic Position

Property Name: GEO

Purpose: This property specifies information related tenth to
the global
position for last day of the activity specified by a calendar component.

Value Type: FLOAT. month.

The value MUST be two SEMICOLON BYYEARDAY rule part specifies a COMMA character (US-ASCII
decimal 44) separated FLOAT
values.

Property Parameters: Non-standard property parameters can be
specified on this property.

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Conformance: This property can be specified in "VEVENT" or "VTODO"
calendar components.

Description: The property value specifies latitude and longitude, in
that order (i.e., "LAT LON" ordering). The longitude represents the
location east or west list of days of the prime meridian as a positive or negative
real number, respectively. The longitude and latitude year. Valid values MAY be
specified up are
1 to six decimal places, which will allow for accuracy 366 or -366 to
within one meter of geographical position. Receiving applications
MUST accept values of this precision and MAY truncate values -1. For example, -1 represents the last day
of
greater precision.

Values for latitude the year (December 31st) and longitude shall be expressed as decimal
fractions of degrees. Whole degrees of latitude shall be represented
by a two-digit decimal number ranging from 0 through 90. Whole
degrees -306 represents the 306th to the
last day of longitude shall be represented by a decimal number ranging
from 0 through 180. When the year (March 1st).

The BYWEEKNO rule part specifies a COMMA character (US-ASCII
decimal fraction of a degree is
specified, it shall be 44) separated from the whole number list of degrees by
a decimal point.

Latitudes north ordinals specifying weeks of the equator shall be specified by a plus sign (+),
year. Valid values are 1 to 53 or by the absence of -53 to -1. This corresponds to
weeks according to week numbering as defined in [ISO.8601.1988].
A week is defined as a minus sign (-), preceding seven day period, starting on the digits
designating degrees. Latitudes south day of
the Equator shall week defined to be
designated by a minus sign (-) preceding the digits designating
degrees. A point on week start (see WKST). Week number one
of the Equator shall be assigned to calendar year is the Northern
Hemisphere.

Longitudes east first week which contains at least
four (4) days in that calendar year. This rule part is only valid
for YEARLY rules. For example, 3 represents the third week of the prime meridian shall be specified by
year.

Note: Assuming a plus
sign (+), Monday week start, week 53 can only occur when
Thursday is January 1 or by the absence of if it is a minus sign (-), preceding the digits
designating degrees. Longitudes west 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 meridian shall be
designated by minus sign (-) preceding the digits designating
degrees. A point on the prime meridian shall be assigned year. Valid values
are 1 to 12.

The WKST rule part specifies the
Eastern Hemisphere. A point day on which the 180th meridian shall be assigned
to the Western Hemisphere. One exception to this last convention workweek starts.
Valid values are MO, TU, WE, TH, FR, SA and SU. This is
permitted. For the special condition of describing
significant when a band of
latitude around the earth, the East Bounding Coordinate data element
shall be assigned the value +180 (180) degrees.

Any spatial address with WEEKLY RRULE has an interval greater than 1,
and a latitude of +90 (90) or -90 degrees will
specify the position at the North or South Pole, respectively. The
component for longitude may have any legal value.

With the exception of the special condition described above, this
form BYDAY rule part is specified specified. This is also significant when
in Department of Commerce, 1986, Representation of
geographic point locations for information interchange (Federal
Information Processing Standard 70-1): Washington, Department of
Commerce, National Institute of Standards and Technology. a YEARLY RRULE when a BYWEEKNO rule part is specified. The
default value is MO.

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The simple formula for converting degrees-minutes-seconds into
decimal degrees is: BYSETPOS rule part specifies a COMMA character (US-ASCII
decimal = degrees + minutes/60 + seconds/3600.

Formal Definition: The property is defined 44) separated list of values which corresponds to the nth
occurrence within the set of events specified by the following notation:

geo = "GEO" geoparam ":" geovalue CRLF

geoparam = *(";" xparam)

geovalue = float ";" float
;Latitude and Longitude components

Example: The following is an 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 represented as:

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

Each BYSETPOS value can include a positive (+n) or negative (-n)
integer. If present, this property:

GEO:37.386013;-122.082932

8.2.7. Location

Property Name: LOCATION

Purpose: The property defines indicates the intended venue for nth occurrence of the activity
defined
specific occurrence within the set of events specified by a calendar component.

Value Type: TEXT

Property Parameters: Non-standard, alternate text representation the
rule.

If BYxxx rule part values are found which are 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 and
language property parameters can be specified on this property.

Conformance: dates are derived from
the Start Time (DTSTART) entry attribute. For example,
"FREQ=YEARLY;BYMONTH=1" doesn't specify a specific day within the
month or a time. This property can information would be the same as what is
specified for DTSTART.

BYxxx rule parts modify the recurrence in "VEVENT" some manner. BYxxx rule
parts for a period of time which is the same or "VTODO"
calendar component.

Description: Specific venues such as conference greater than the
frequency generally reduce or meeting rooms may
be explicitly specified using this property. An alternate
representation may be specified that is a URI that points to
directory information with more structured specification limit the number of occurrences of
the
location. recurrence generated. For example, "FREQ=DAILY;BYMONTH=1"
reduces the alternate representation may specify
either an LDAP URI pointing to an LDAP server entry or a CID URI
pointing number of recurrence instances from all days (if
BYMONTH tag is not present) to a MIME body part containing a vCard [RFC 2426] all days in January. BYxxx rule
parts for a period of time less than the
location.

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Format Definition: The property is defined by frequency generally
increase or expand the following notation:

location = "LOCATION locparam ":" text CRLF

locparam = *(

; number of occurrences of the following are optional,
; but MUST NOT occur more than once

(";" altrepparam) / (";" languageparam) /

; recurrence.
For example, "FREQ=YEARLY;BYMONTH=1,2" increases the following is optional,
; and MAY occur more than once

(";" 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

8.2.8. Percent Complete

Property Name: PERCENT-COMPLETE

Purpose: This property is used by an assignee or delegatee number of a to-do
to convey
days within the percent completion of a to-do yearly recurrence set from 1 (if BYMONTH tag is
not present) to 2.

If multiple BYxxx rule parts are specified, then after evaluating
the Organizer.

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 FREQ and one hundred. A value of "0" indicates INTERVAL rule parts, the to-do has not yet been
started. A value of "100" indicates that BYxxx rule parts
are applied to the to-do has been
completed. Integer values current set of evaluated occurrences in between indicate the percent partially
complete.

When a to-do
following order: BYMONTH, BYWEEKNO, BYYEARDAY, BYMONTHDAY, BYDAY,
BYHOUR, BYMINUTE, BYSECOND and BYSETPOS; then COUNT and UNTIL are
evaluated.

Here is assigned to multiple individuals, the property value
indicates the percent complete for that portion an example of the to-do assigned evaluating multiple BYxxx rule parts.

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

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to June 2006

First, the assignee or delegatee. For example, if a to-do is assigned "INTERVAL=2" would be applied to
both individuals "A" "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 "B". A reply 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 "A" with a percent
complete of "70" indicates that "A" has completed 70% of RRULE, the to-do
assigned second is derived from DTSTART, to them. A reply end
up in "every Sunday in January at 8:30:00 AM and 9:30:00 AM, every
other year". Similarly, if the BYMINUTE, BYHOUR, BYDAY,
BYMONTHDAY or BYMONTH rule part were missing, the appropriate
minute, hour, day or month would have been retrieved from "B" with the
"DTSTART" property.

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

Example: The following is a percent complete of "50"
indicates "B" has completed 50% of rule which specifies 10 meetings which
occur every other day:

FREQ=DAILY;COUNT=10;INTERVAL=2

There are other examples specified in the to-do assigned "RRULE" specification.

3.3.11. Text

Value Name: TEXT

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

Format Definition: The property character sets supported by this revision of
iCalendar are UTF-8 and US-ASCII thereof. The applicability to
other character sets is for future work. The value type is
defined by the following notation:

percent notation.

text = "PERCENT-COMPLETE" pctparam *(TSAFE-CHAR / ":" integer CRLF

pctparam / DQUOTE / ESCAPED-CHAR)
; Folded according to description above

ESCAPED-CHAR = *(";" xparam)

Example: The following is an example "\\" / "\;" / "\," / "\N" / "\n")
; \\ encodes \, \N or \n encodes newline
; \; encodes ;, \, encodes ,

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

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Note: Certain other character sets may require modification of
the above definitions, but this property to show 39%
completion:

PERCENT-COMPLETE:39

8.2.9. Priority

Property Name: PRIORITY

Purpose: The property defines is beyond the relative priority for a calendar
component.

Value Type: INTEGER

Property Parameters: Non-standard property parameters can be
specified on scope of this property.

Conformance: The
document.

Description: If the property can be permits, multiple "text" values are
specified in by a "VEVENT" or "VTODO"
calendar component.

Description: The priority is specified as an integer in the range
zero to nine. A value of zero (US-ASCII decimal 48) specifies an
undefined priority. A value of one COMMA character (US-ASCII decimal 49) is the
highest priority. A value 44) separated
list of two (US-ASCII decimal 50) is values.

The language in which the second
highest priority. Subsequent numbers specify a decreasing ordinal
priority. A value of nine (US-ASCII decimal 58) text is represented can be controlled by
the lowest
priority.

A CUA with a three-level priority scheme of "HIGH", "MEDIUM" and
"LOW" is mapped into this "LANGUAGE" property such that parameter.

An intentional formatted text line break MUST only be included in
a "TEXT" property value in by representing the
range line break with the
character sequence of one BACKSLASH (US-ASCII decimal 49) to four 92), followed by
a LATIN SMALL LETTER N (US-ASCII decimal 52)
specifies "HIGH" priority. A value of five 110) or a LATIN CAPITAL
LETTER N (US-ASCII decimal 53) 78), that is
the normal "\n" or "MEDIUM" priority. A value in the range of six (US-
ASCII decimal 54) "\N".

The "TEXT" property values may also contain special characters
that are used to nine (US-ASCII decimal 58) is "LOW" priority.

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A CUA with signify delimiters, such as a priority schema COMMA character for
lists of "A1", "A2", "A3", "B1", "B2", ...,
"C3" is mapped into this property such that values or a property value SEMICOLON character for structured values.
In order to support the inclusion of one these special characters in
"TEXT" property values, they MUST be escaped with a BACKSLASH
character. A BACKSLASH character (US-ASCII decimal 49) specifies "A1", 92) in a
"TEXT" property value of two (US-
ASCII decimal 50) specifies "A2", MUST be escaped with another BACKSLASH
character. A COMMA character in a "TEXT" property value of three MUST be
escaped with a BACKSLASH character (US-ASCII decimal 51) specifies "A3", and so forth up to 92). A
SEMICOLON character in a "TEXT" property value of 9 MUST be escaped
with a BACKSLASH character (US-ASCII decimal 58) specifies "C3".

Other integer values are reserved for future use.

Within 92). However, a "VEVENT" calendar component, this property specifies
COLON character in a
priority for the event. This "TEXT" property may value SHALL NOT be useful when more than
one event is scheduled for a given time period.

Within a "VTODO" calendar component, this property specified escaped
with a
priority for the to-do. 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\nConference Room - 3B\nCome Prepared.

3.3.12. Time

Value Name: TIME

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Purpose: This property value type is useful in prioritizing
multiple action items for used to identify values that contain a given
time period. of day.

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

priority

time = "PRIORITY" prioparam ":" privalue CRLF
;Default is zero

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

time-hour = *(";" xparam)

privalue 2DIGIT ;00-23
time-minute = integer ;Must be in 2DIGIT ;00-59
time-second = 2DIGIT ;00-60
;The "60" value is used to account for "leap" seconds.

time-utc = "Z"

Description: If the range [0..9]
; All other property permits, multiple "time" values are reserved
specified by a COMMA character (US-ASCII decimal 44) separated
list of values. No additional content value encoding (i.e.,
BACKSLASH character encoding) is defined for future use this value type.

The following "TIME" data type is an example of used to identify values that contain a property with the highest priority:

PRIORITY:1
time of day. The following format is an example of a property with based on the [ISO.8601.1988] complete
representation, basic format for a next highest
priority:

PRIORITY:2

Example: time of day. The following is an example text format
consists of a property with no priority.
This is equivalent to not specifying two-digit 24-hour of the "PRIORITY" property:

PRIORITY:0

8.2.10. Resources

Property Name: RESOURCES

Purpose: This property defines day (i.e., values 0-23),
two- digit minute in the equipment or resources anticipated
for an activity specified by a calendar entity..

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Value Type: TEXT

Property Parameters: Non-standard, alternate text representation hour (i.e., values 0-59), and
language property parameters can be specified on this property.

Conformance: This property can be specified two-digit
seconds in "VEVENT" or "VTODO"
calendar component.

Description: the minute (i.e., values 0-60). The property seconds value is an arbitrary text. More than one
resource can of
60 MUST only to be specified as a list used to account for "leap" seconds. Fractions
of resources separated by the
COMMA character (US-ASCII decimal 44).

Format Definition: The property is defined a second are not supported by this format.

In parallel to the following notation:

resources = "RESOURCES" resrcparam ":" text *("," text) CRLF

resrcparam = *(

; "DATE-TIME" definition above, the following are optional,
; but "TIME" data
type expresses time values in three forms:

The form of time with UTC offset MUST NOT occur more than once

(";" altrepparam) / (";" languageparam) /

; be used. For example,
the following is optional,
; and MAY occur more than once

(";" xparam)

)

Example: The following is an example of this property:

RESOURCES:EASEL,PROJECTOR,VCR

RESOURCES;LANGUAGE=fr:1 raton-laveur

8.2.11. Free/Busy Time Type

Parameter Name: FBTYPE

Purpose: To specify the free or busy NOT VALID for a time type.

Description: The parameter specifies the free or busy value:

230000-0800 ;Invalid time type. format

FORM #1 LOCAL TIME

The
value FREE indicates that the local time interval form is free for scheduling.
The simply a time value BUSY indicates that the time interval is busy because one does not contain
the UTC designator nor does it reference a time zone. For
example, 11:00 PM:

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or more events have been scheduled for that interval. The value
BUSY-UNAVAILABLE indicates that June 2006

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, and second value regardless of which time interval
zone is busy and currently being observed. For example, 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 interval person is
in. In these cases, a local time can not be scheduled. specified. The recipient
of an iCalendar object with a property value BUSY-TENTATIVE
indicates that consisting of a local
time, without any relative time zone information, SHOULD interpret
the value as being fixed to whatever time interval zone the ATTENDEE is busy because one or more events
have been tentatively scheduled for that interval. If not specified
on a property in
at any given moment. This means that allows this parameter, two ATTENDEEs may
participate in the default same event at different UTC times; floating
time SHOULD only be used where that is BUSY.

Format Definition: The property parameter reasonable behavior.

In most cases, a fixed time is defined by the following
notation:

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

; Some other IANA registered iCalendar data type.

Example: 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 is an example use of this parameter on local time in a FREEBUSY
property.

FREEBUSY;FBTYPE=BUSY:19980415T133000Z/19980415T170000Z

8.2.12. Participation Status

Parameter Name: PARTSTAT

Purpose: To specify the participation status for the calendar user
specified by TIME value without the property.

Description: This TZID property
parameter can is to be specified on properties with interpreted as a
CAL-ADDRESS value type. The parameter identifies the participation
status for local time value, regardless
of the existence of "VTIMEZONE" calendar user specified components in the
iCalendar object.

FORM #2: UTC TIME

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

070000Z

The TZID property parameter MUST NOT be applied to TIME properties
whose time values differ depending on whether they are associated with
a group scheduled "VEVENT", "VTODO" or "VJOURNAL". specified in UTC.

FORM #3: LOCAL TIME AND TIME ZONE REFERENCE

The values MUST
match one of local time with reference to time zone information form is
identified by the values allowed for use the given calendar component. If
not specified on a TZID property that allows this parameter, parameter to reference the default
value
appropriate time zone definition. TZID is NEEDS-ACTION. discussed in detail in
the section on Time Zone.

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Format Definition: June 2006

Example: The property parameter is defined by the 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 "VEVENT".
; Default is 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 has
;date/time completed.
/ "IN-PROCESS" ; To-do represents 8:30 AM in process New York in Winter, five
hours behind UTC, in each of
; being completed
/ x-name ; Experimental status
/ iana-token) ; Other IANA registered
; status
; These are the participation statuses for a "VTODO". Default is
; 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 three formats using the participation statuses for a "VJOURNAL".
; Default is NEEDS-ACTION

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Example:

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

8.2.13. Status

Property "X-
TIMEOFDAY" non-standard property:

X-TIMEOFDAY:083000

X-TIMEOFDAY:133000Z

X-TIMEOFDAY;TZID=US-Eastern:083000

3.3.13. URI

Value Name: STATUS URI

Purpose: This property defines the overall status or confirmation for
the calendar component.

Value Type: TEXT

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This property can be specified in "VEVENT", "VTODO" or
"VJOURNAL" calendar components.

Description: In value type is used to identify values that contain a group scheduled calendar component,
uniform resource identifier (URI) type of reference to the
property value.

Format Definition: The data type is
used defined by the "Organizer" following
notation:

uri = <As defined by any IETF RFC>

Description: This data type might be used to provide a confirmation of the event reference binary
information, for values that are large, or otherwise undesirable
to the
"Attendees". For example include directly in a "VEVENT" calendar component, the
"Organizer" iCalendar object.

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

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

When a meeting property parameter value is tentative, confirmed or
cancelled. In a "VTODO" calendar component, URI value type, the "Organizer" can
indicate that an action item needs action, URI MUST
be specified as a quoted-string value.

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

Example: The following is in
process or being worked on, or has been cancelled. In a "VJOURNAL"
calendar component, the "Organizer" can indicate that URI for a journal entry
is draft, final or has been cancelled or removed. network file:

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

3.3.14. UTC Offset

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Value Name: UTC-OFFSET

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

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

status

utc-offset = "STATUS" statparam] ":" statvalue CRLF

statparam time-numzone ;As defined above in time data type

time-numzone = *(";" xparam)

statvalue = "TENTATIVE" ;Indicates event is
;tentative.
/ "CONFIRMED" ;Indicates event is
;definite. ("+" / "CANCELLED" ;Indicates event was
;cancelled.
;Status values "-") time-hour time-minute [time-
second]

Description: The PLUS SIGN character MUST be specified for a "VEVENT"

statvalue =/ "NEEDS-ACTION" ;Indicates to-do needs action.
/ "COMPLETED" ;Indicates to-do completed.
/ "IN-PROCESS" ;Indicates to-do in process positive
UTC offsets (i.e., ahead of
/ "CANCELLED" ;Indicates to-do was cancelled.
;Status values UTC). The MINUS SIGN character MUST
be specified for "VTODO".

statvalue =/ "DRAFT" ;Indicates journal is draft.
/ "FINAL" ;Indicates journal is final.
/ "CANCELLED" ;Indicates journal negative UTC offsets (i.e., behind of UTC). The
value of "-0000" and "-000000" are not allowed. The time-second,
if present, may not be 60; if absent, it defaults to zero.

No additional content value encoding (i.e., BACKSLASH character
encoding) is removed.
;Status values defined for "VJOURNAL". this value type.

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

-0500

+0100

3.4. iCalendar Object

The Calendaring and Scheduling Core Object is an example a collection of
calendaring and scheduling information. Typically, this property for information
will consist of a "VEVENT"
calendar component:

STATUS:TENTATIVE 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 = 1*("BEGIN" ":" "VCALENDAR" CRLF
icalbody
"END" ":" "VCALENDAR" CRLF)

The following is an a simple example of this an iCalendar object:

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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

3.5. Property

A property for is the definition of an individual attribute describing a "VTODO"
calendar
component:

STATUS:NEEDS-ACTION or a calendar component. A property takes the form defined
by the "contentline" notation defined in Section 3.1.

The following is an example of this property for a "VJOURNAL"
calendar component:

STATUS:DRAFT

8.2.14. Summary

Property Name: SUMMARY

Purpose: property:

DTSTART:19960415T133000Z

This property defines a short summary or subject for the
calendar component.

Value Type: TEXT

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object.

Property Parameters: Non-standard, alternate text representation names, parameter names and
language enumerated parameter values are
case insensitive. For example, the property parameters can be specified on this property.

Conformance: name "DUE" is the same
as "due" and "Due", DTSTART;TZID=US-Eastern:19980714T120000 is the
same as DtStart;TzID=US-Eastern:19980714T120000.

3.6. Calendar Components

The property can be specified in "VEVENT", "VTODO",
"VJOURNAL" body of the iCalendar object consists of a sequence of calendar
properties and one or "VALARM" more calendar components.

Description: This property is used in The calendar
properties are attributes that apply to the "VEVENT", "VTODO" and
"VJOURNAL" calendar as a whole. The
calendar components to capture are collections of properties that express a short, one line summary
about the activity or journal entry.

This property is used in
particular calendar semantic. For example, the "VALARM" calendar component to capture
the subject of
can specify an event, a to-do, a journal entry, time zone
information, or free/busy time information, or an EMAIL category of alarm.

Format Definition:

The property body of the iCalendar object is defined by the following
notation:

summary = "SUMMARY" summparam ":" text CRLF

summparam = *(

; the following

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icalbody = calprops component

calprops = 2*(

; 'prodid' and 'version' are optional, both REQUIRED,
; but MUST NOT occur more than once

(";" altrepparam) / (";" languageparam)

prodid /version /

; the following is 'calscale' and 'method' are optional,
; and MAY but MUST NOT occur more than once

(";" xparam)

calscale /
method /

x-prop
)

Example: The following is an example of this property:

SUMMARY:Department Party

8.2.15. Date and Time Component Properties

The following properties specify date and time related information in
calendar components.

8.2.15.1. Date/Time Completed

Property Name: COMPLETED

Purpose: This property defines the date and time that a to-do was
actually completed.

Value Type: DATE-TIME

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Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: The property can be specified in a "VTODO" calendar
component.

Description: The date and time MUST be in a UTC format.

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

completed

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

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

compparam

1*contentline

"END" ":" iana-token CRLF

x-comp = *(";" xparam)

Example: The following is an example of this property:

COMPLETED:19960401T235959Z

8.2.15.2. Date/Time End

Property Name: DTEND

Purpose: This property specifies "BEGIN" ":" x-name CRLF

1*contentline

"END" ":" x-name CRLF

An iCalendar object MUST include the date "PRODID" and time that a "VERSION" calendar
component ends.

Value Type: The default value type is DATE-TIME. The value type can
be set
properties. In addition, it MUST include at least one calendar
component. Special forms of iCalendar objects are possible to
publish just busy time (i.e., only a DATE value type.

Property Parameters: Non-standard, value data type, "VFREEBUSY" calendar component)
or time zone
identifier property parameters can be specified on this property.

Conformance: This property can be specified in "VEVENT" or
"VFREEBUSY" (i.e., only a "VTIMEZONE" calendar components.

Description: Within component)
information. In addition, a complex iCalendar object is possible
that is used to capture a complete snapshot of the "VEVENT" contents of a
calendar component, this property
defines the date and time by which the event ends. The value MUST be
later in time than the value (e.g., composite of the "DTSTART" property.

Within the "VFREEBUSY" many different calendar component, this property defines the
end date and time for the free or busy time information. The time
MUST be specified in the UTC time format. The value MUST be later in
time than the value components).
More commonly, an iCalendar object will consist of the "DTSTART" property. just a single
"VEVENT", "VTODO" or "VJOURNAL" calendar component.

3.6.1. Event Component

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Component Name: VEVENT

Purpose: Provide a grouping of component properties that describe an
event.

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

dtend

eventc = "DTEND" dtendparam":" dtendval "BEGIN" ":" "VEVENT" CRLF

dtendparam
eventprop *alarmc
"END" ":" "VEVENT" CRLF

eventprop = *(

; the following are optional,
; but MUST NOT occur more than once

(";" "VALUE" "=" ("DATE-TIME"

class / "DATE")) created /
(";" tzidparam) description /

; the following is optional,
; and MAY occur more than once

(";" xparam)

)

dtendval = date-time dtstart / geo /
last-mod / location / organizer / priority /
dtstamp / seq / status / summary / transp /
uid / url / recurid / date
;Value MUST match value type

Example: The following is an example of this property:

DTEND:19960401T235959Z

DTEND;VALUE=DATE:19980704

8.2.15.3. Date/Time Due

Property Name: DUE

Purpose: This property defines the date and time that a to-do is
expected to be completed.

Value Type: The default value type is DATE-TIME. The value type can
be set to a DATE value type.

Property Parameters: Non-standard, value data type, time zone
identifier property parameters can be specified on this property.

Conformance: The property can be specified once in a "VTODO" calendar
component.

Description: The value MUST be a date/time equal to or after the
DTSTART value, if specified.

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

due = "DUE" dueparam":" dueval CRLF

dueparam = *(

; the following are optional, either 'dtend' or 'duration' may appear in
; a 'eventprop', but 'dtend' and 'duration'
; MUST NOT occur more than once

(";" "VALUE" "=" ("DATE-TIME" / "DATE")) in the same 'eventprop'

dtend /
(";" tzidparam) duration /

; the following is are optional,
; and MAY occur more than once

*(";" xparam)

)

dueval = date-time

attach / date
;Value MUST match value type

Example: The following is an example of this property:

DUE:19980430T235959Z

8.2.15.4. Date/Time Start

Property Name: DTSTART

Purpose: This property specifies when the attendee / categories / comment /
contact / exdate / exrule / rstatus / related /
resources / rdate / rrule / x-prop

)

Description: A "VEVENT" calendar component begins.

Value Type: The default value type is DATE-TIME. The a grouping of component
properties, and possibly including "VALARM" calendar components,
that represents a scheduled amount of time value MUST on a calendar. For
example, it can be one of 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 forms defined
event will appear as an opaque interval in a search for busy time.
Alternately, the DATE-TIME value type. The value
type event can be have its Time Transparency set to
"TRANSPARENT" in order to prevent blocking of the event in
searches for busy time.

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The "VEVENT" is also the calendar component used to specify an
anniversary or daily reminder within a calendar. These events
have a DATE value type.

Property Parameters: Non-standard, value data type, time zone
identifier type for the "DTSTART" property parameters can instead of the
default data type of DATE-TIME. If such a "VEVENT" has a "DTEND"
property, it MUST be specified on this property.

Conformance: This property as a DATE value also. The
anniversary type of "VEVENT" can be specified in the "VEVENT", "VTODO",
"VFREEBUSY", or "VTIMEZONE" span more than one date (i.e,
"DTEND" property value is set to a calendar components.

Description: Within date after the "VEVENT" calendar component, this
"DTSTART" property
defines value).

The "DTSTART" property for a "VEVENT" specifies the inclusive
start date and time for of the event. For recurring events, it also specifies the
very first instance in the recurrence set. The "DTEND" property is
REQUIRED in
for a "VEVENT" calendar components. Events can have a start
date/time but no component specifies the non-inclusive end date/time. In that case,
of the event does not

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take up any time.

Within the "VFREEBUSY" event. For cases where a "VEVENT" calendar component, this component
specifies a "DTSTART" property defines with a DATE data type but no
"DTEND" property, the
start date and time for events non-inclusive end is the free or busy time information. The time
MUST be end of the
calendar date specified in UTC time.

Within by the "VTIMEZONE" "DTSTART" property. For cases
where a "VEVENT" calendar component, this component specifies a "DTSTART" property defines
with a DATE-TIME data type but no "DTEND" property, the
effective start event ends
on the same calendar date and time of day specified by the
"DTSTART" property.

The "VEVENT" calendar component cannot be nested within another
calendar component. However, "VEVENT" calendar components can be
related to each other or to a "VTODO" or to a "VJOURNAL" calendar
component with the "RELATED-TO" property.

Example: The following is an example of the "VEVENT" calendar
component used to represent a meeting that will also be opaque to
searches for busy time:

BEGIN:VEVENT
UID:19970901T130000Z-123401@host.com
DTSTAMP:19970901T130000Z
DTSTART:19970903T163000Z
DTEND:19970903T190000Z
SUMMARY:Annual Employee Review
CLASS:PRIVATE
CATEGORIES:BUSINESS,HUMAN RESOURCES
END:VEVENT

The following is an example of the "VEVENT" calendar component
used to represent a time zone specification. This
property reminder that will not be opaque, but rather
transparent, to searches for busy time:

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BEGIN:VEVENT
UID:19970901T130000Z-123402@host.com
DTSTAMP:19970901T130000Z
DTSTART:19970401T163000Z
DTEND:19970402T010000Z
SUMMARY:Laurel is REQUIRED within each STANDARD and DAYLIGHT part included in "VTIMEZONE" sensitivity awareness class.
CLASS:PUBLIC
CATEGORIES:BUSINESS,HUMAN RESOURCES
TRANSP:TRANSPARENT
END:VEVENT

The following is an example of the "VEVENT" calendar components and MUST be specified component
used to represent an anniversary that will occur annually. Since
it takes up no time, it will not appear as opaque in a local
DATE-TIME without search for
busy time; no matter what the "TZID" value of the "TRANSP" property parameter.
indicates:

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

3.6.2. To-do Component

Component Name: VTODO

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

Format Definition: The property A "VTODO" calendar component is defined by the
following notation:

dtstart

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todoc = "DTSTART" dtstparam "BEGIN" ":" dtstval "VTODO" CRLF

dtstparam
todoprop *alarmc
"END" ":" "VTODO" CRLF

todoprop = *(

; the following are optional,
; but MUST NOT occur more than once

(";" "VALUE" "=" ("DATE-TIME"

class / "DATE")) completed /
(";" tzidparam) created / description / dtstamp /
dtstart / geo / last-mod / location / organizer /
percent / priority / recurid / seq / status /
summary / uid / url /

; either 'due' or 'duration' may appear in
; a 'todoprop', but 'due' and 'duration'
; MUST NOT occur in the same 'todoprop'

due / duration /

; the following is are optional,
; and MAY occur more than once

*(";" xparam)

)

dtstval = date-time
attach / date
;Value MUST match value type

Example: The following attendee / categories / comment / contact /
exdate / exrule / rstatus / related / resources /
rdate / rrule / x-prop

)

Description: A "VTODO" calendar component is an example of this property:

DTSTART:19980118T073000Z

8.2.15.5. Duration

Property Name: DURATION

Purpose: The property specifies a positive duration grouping of time.

Value Type: DURATION

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Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: The property can be specified in "VEVENT", "VTODO",
"VFREEBUSY" or component
properties and possibly "VALARM" calendar components.

Description: In a "VEVENT" calendar component the property may components that
represent an action-item or assignment. For example, it can be
used to specify a duration of the event, instead represent an item of work assigned to an explicit end
date/time. In a individual; such
as "turn in travel expense today".

The "VTODO" calendar component the property may cannot be used nested within another
calendar component. However, "VTODO" calendar components can be
related to each other or to specify a duration for the to-do, instead of an explicit due date/
time. In "VTODO" or to a "VFREEBUSY" "VJOURNAL" calendar
component with the property may be used
to specify the interval of free time being requested. In a "VALARM" "RELATED-TO" property.

A "VTODO" calendar component without the property may "DTSTART" and "DUE" (or
"DURATION") properties specifies a to-do that will be used to specify the delay
period prior to repeating an alarm.

Format Definition: The property associated
with each successive calendar date, until it is defined by the following notation:

duration = "DURATION" durparam ":" dur-value CRLF
;consisting of a positive duration of time.

durparam = *(";" xparam) completed.

Example: 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

The following is an example of this property that specifies an
interval of time of 15 minutes.

DURATION:PT15M

8.2.15.6. Free/Busy Time

Property Name: FREEBUSY

Purpose: The property defines one or more free or busy time
intervals.

Value Type: 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: The property can be specified in a "VFREEBUSY" "VTODO" calendar
component. component:

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Property Parameter: "FBTYPE" and non-standard parameters can be
specified on this property.

Description: These time periods can be specified as either a start
and end date-time or a start date-time and duration. The date and
time MUST be June 2006

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

3.6.3. Journal Component

Component Name: VJOURNAL

Purpose: Provide a UTC time format.

"FREEBUSY" properties within the "VFREEBUSY" calendar component
SHOULD be sorted in ascending order, based on start time and then end
time, with the earliest periods first.

The "FREEBUSY" property can specify more than one value, separated by
the COMMA character (US-ASCII decimal 44). In such cases, the
"FREEBUSY" property values SHOULD all be of the same "FBTYPE"
property parameter type (e.g., all values grouping of component properties that describe a particular "FBTYPE"
listed together in a single property).
journal entry.

Format Definition: The property A "VJOURNAL" calendar component is defined by the
following notation:

freebusy

journalc = "FREEBUSY" fbparam "BEGIN" ":" fbvalue "VJOURNAL" CRLF

fbparam
jourprop
"END" ":" "VJOURNAL" CRLF

jourprop = *(

; the following is are optional,
; but MUST NOT occur more than once

(";" fbtypeparam)

class / created / description / dtstart / dtstamp /
last-mod / organizer / recurid / seq / status /
summary / uid / url /

; the following is are optional,
; and MAY occur more than once

(";" xparam)

attach / attendee / categories / comment /
contact / exdate / exrule / related / rdate /
rrule / rstatus / x-prop
)

fbvalue = period *["," period]
;Time value MUST be in the UTC time format.

Example: The following are some examples

Description: A "VJOURNAL" calendar component is a grouping of this property:

FREEBUSY;FBTYPE=BUSY-UNAVAILABLE:19970308T160000Z/PT8H30M

FREEBUSY;FBTYPE=FREE:19970308T160000Z/PT3H,19970308T200000Z/PT1H

FREEBUSY;FBTYPE=FREE:19970308T160000Z/PT3H,19970308T200000Z/PT1H,
19970308T230000Z/19970309T000000Z
component properties that represent one or more descriptive text
notes associated with a particular calendar date. The "DTSTART"
property is used to specify the calendar date that the journal
entry is associated with. Generally, it will have a DATE value

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8.2.15.7. Time Transparency

Property Name: TRANSP

Purpose: This property defines whether an event is transparent or not
to busy time searches.

Value Type: TEXT

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This property June 2006

data type, but it can also be specified once in used to specify a "VEVENT"
calendar component.

Description: Time Transparency is the characteristic DATE-TIME value
data type. Examples of an event that
determines whether it appears to consume time on a calendar. Events
that consume actual time journal entry include a daily record of
a legislative body or a journal entry of individual telephone
contacts for the individual day or resource associated

with an ordered list of accomplishments for the
day. The "VJOURNAL" calendar SHOULD component can also be recorded as OPAQUE, allowing them used to be
detected by free-busy time searches. Other events, which do
associate a document with a calendar date.

The "VJOURNAL" calendar component does not take up the individual's (or resource's) time SHOULD be recorded as
TRANSPARENT, making them invisible to free-busy time searches.

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

transp = "TRANSP" tranparam ":" transvalue CRLF

tranparam = *(";" xparam)

transvalue = "OPAQUE" ;Blocks or opaque on a
calendar. Hence, it does not play a role in free or busy time searches.
/ "TRANSPARENT" ;Transparent on busy
searches - - it is as though it has a time searches.
;Default transparency value is OPAQUE

Example: The following is an example of this property for an event
that
TRANSPARENT. It is transparent to any such searches.

The "VJOURNAL" calendar component cannot be nested within another
calendar component. However, "VJOURNAL" calendar components can
be related to each other or does not block on free/busy time searches:

TRANSP:TRANSPARENT to a "VEVENT" or to a "VTODO" calendar
component, with the "RELATED-TO" property.

Example: The following is an example of this property for an event that the "VJOURNAL" calendar
component:

BEGIN:VJOURNAL
UID:19970901T130000Z-123405@host.com
DTSTAMP:19970901T130000Z
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
opaque or blocks 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 demo by Friday.\n
3. Henry Miller (Handsoff Insurance): Car was totaled by tree.
Is looking into a loaner car. 654-2323 (tel).
END:VJOURNAL

3.6.4. Free/Busy Component

Component Name: VFREEBUSY

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 searches:

TRANSP:OPAQUE or describe a published set of busy
time.

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

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8.2.16. Time Zone Component Properties

The following properties specify time zone information in calendar
components.

8.2.16.1. Time Zone Identifier

Property Name: TZID

Purpose: This property specifies the text value that uniquely
identifies the "VTIMEZONE" calendar component.

Value Type: TEXT

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This property MUST be specified in a "VTIMEZONE"
calendar component.

Description: This is the label by which a time zone calendar
component is referenced by any iCalendar properties whose data type
is either DATE-TIME or TIME and not intended to specify a UTC or a
"floating" time. The presence of the SOLIDUS character (US-ASCII
decimal 47) as a prefix, indicates that this TZID represents an
unique ID in a globally defined time zone registry (when such
registry is defined).

Note: This document does not define a naming convention for time zone
identifiers. Implementers may want to use the naming conventions
defined in existing time zone specifications such as the public-
domain Olson database [TZ]. The specification of globally unique
time zone identifiers is not addressed by this document and is left
for future study.

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

tzid June 2006

freebusyc = "TZID" tzidpropparam "BEGIN" ":" [tzidprefix] text "VFREEBUSY" CRLF

tzidpropparam = *(";" xparam)

;tzidprefix = "/"
; Defined previously. Just listed here for reader convenience.

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Example: The following are examples of non-globally unique time zone
identifiers:

TZID:US-Eastern

TZID:California-Los_Angeles

The following is an example of a fictitious globally unique time zone
identifier:

TZID:/US-New_York-New_York

8.2.16.2. Time Zone Name

Property Name: TZNAME

Purpose: This property specifies the customary designation for a time
zone description.

Value Type: TEXT

Property Parameters: Non-standard and language property parameters
can be specified on this property.

Conformance: This property can be specified in a "VTIMEZONE" calendar
component.

Description: This property may be specified in multiple languages; in
order to provide for different language requirements.

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

tzname = "TZNAME" tznparam
fbprop
"END" ":" text "VFREEBUSY" CRLF

tznparam

fbprop = *(

; the following is are optional,
; but MUST NOT occur more than once

(";" languageparam)

contact / dtstart / dtend / duration / dtstamp /
organizer / uid / url /

; the following is are optional,
; and MAY occur more than once

(";" xparam)

attendee / comment / freebusy / rstatus / x-prop
)

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Example: The following are example of this property:

TZNAME:EST

Figure 97

The following

Description: A "VFREEBUSY" calendar component is an example a grouping of this property when two different
languages
component properties that represents either a request for, a reply
to a request for the free or busy time zone name are specified:

TZNAME;LANGUAGE=en:EST
TZNAME;LANGUAGE=fr-CA:HNE

8.2.16.3. Time Zone Offset From

Property Name: TZOFFSETFROM

Purpose: This property specifies the offset which is in use prior information or a published set
of busy time information.

When used to
this request free/busy 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.

Description: This information, the "ATTENDEE"
property specifies the offset which is in use prior
to this calendar users whose free/busy time observance. It is used to calculate
being requested; the absolute time
at which "ORGANIZER" property specifies the transition to a given observance takes place. This
property MUST only be specified in a "VTIMEZONE" calendar component.
A "VTIMEZONE" calendar component MUST include this property. The
property value
user who is a signed numeric indicating requesting the number of hours free/busy time; the "DTSTART" and
possibly minutes from UTC. Positive numbers represent time zones
east of
"DTEND" properties specify the prime meridian, or ahead window of UTC. Negative numbers
represent time zones west of for which the prime meridian, or behind UTC.

Format Definition: The property free/
busy time is defined by being requested; the following notation:

tzoffsetfrom = "TZOFFSETFROM" frmparam ":" utc-offset
CRLF

frmparam = *(";" xparam)

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Example: The following "UID" and "DTSTAMP" properties
are examples specified to assist in proper sequencing of this property:

TZOFFSETFROM:-0500

TZOFFSETFROM:+1345

Figure 100

8.2.16.4. Time Zone Offset To

Property Name: TZOFFSETTO

Purpose: This multiple free/busy
time requests.

When used to reply to a request for free/busy time, the "ATTENDEE"
property specifies the offset which is in use in this calendar user responding to the free/busy
time zone observance.

Value Type: UTC-OFFSET

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This request; the "ORGANIZER" property MUST be specified in a "VTIMEZONE" specifies the calendar component.

Description: This user
that originally requested the free/busy time; the "FREEBUSY"
property specifies the offset which is in use free/busy time information (if it exists);
and the "UID" and "DTSTAMP" properties are specified to assist in
this
proper sequencing of multiple free/busy time zone observance. It is replies.

When used to calculate the absolute time
for publish busy time, the new observance. The "ORGANIZER" property value is a signed numeric
indicating specifies
the number of hours calendar user associated with the published busy time; the
"DTSTART" and possibly minutes from UTC.
Positive numbers represent "DTEND" properties specify an inclusive time zones east of window
that surrounds the prime meridian, or
ahead of UTC. Negative numbers represent busy time zones west of information; the
prime meridian, or behind UTC.

Format Definition: The "FREEBUSY" property is defined by
specifies the following notation:

tzoffsetto = "TZOFFSETTO" toparam ":" utc-offset CRLF

toparam = *(";" xparam)

Example: The following are examples of this property:

TZOFFSETTO:-0400

TZOFFSETTO:+1245

Figure 102 published busy time information; and the "DTSTAMP"
property specifies the date/time that iCalendar object was
created.

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8.2.16.5. Time Zone URL

Property Name: TZURL

Purpose: June 2006

The TZURL provides a means for a VTIMEZONE "VFREEBUSY" calendar component to
point to a network location that can cannot be used to retrieve an up-to-
date version of itself.

Value Type: URI

Property Parameters: Non-standard property parameters nested within another
calendar component. Multiple "VFREEBUSY" calendar components can
be specified on this within an iCalendar object. This permits the
grouping of Free/Busy information into logical collections, such
as monthly groups of busy time information.

The "VFREEBUSY" 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 the
associated replies.

Free/Busy information is represented with the "FREEBUSY" property.

Conformance:
This property provides a terse representation of time periods.
One or more "FREEBUSY" properties can be specified in a "VTIMEZONE" the
"VFREEBUSY" calendar component.

Description: The TZURL provides a means for a VTIMEZONE component to
point to

When present in a network location that can "VFREEBUSY" calendar component, the "DTSTART"
and "DTEND" properties SHOULD be used specified prior to retrieve an up-to-
date version of itself. This provides any "FREEBUSY"
properties. In a hook to handle changes
government bodies impose upon free time zone definitions. Retrieval of
this resource results request, these properties can be used
in an iCalendar object containing a single
VTIMEZONE component and a METHOD combination with the "DURATION" property set to PUBLISH.

Format Definition: represent a request
for a duration of free time within a specified window of time.

The property is defined by 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 following notation:

tzurl = "TZURL" tzurlparam ":" uri CRLF

tzurlparam = *(";" xparam) "FREEBUSY" property.

Example: The following is an example of this property:

TZURL:http://timezones.r.us.net/tz/US-California-Los_Angeles.ics

8.2.17. Relationship Component Properties

The following properties specify relationship information in a "VFREEBUSY" calendar
components.

8.2.17.1. Attendee

Property Name: ATTENDEE

Purpose:
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
END:VFREEBUSY

The property defines following is an "Attendee" within example of a "VFREEBUSY" calendar
component.

Value Type: CAL-ADDRESS

Property Parameters: Non-standard, language, calendar user type, component
used to reply to the request with busy time information:

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group or list membership, participation role, participation status,
RSVP expectation, delegatee, delegator, sent by, common name or
directory entry reference 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
NOT be specified in an June 2006

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 object when publishing the calendar file contains busy time information (e.g., NOT in an iCalendar object that specifies for
the
publication next three months.
END:VFREEBUSY

The following is an example of a "VFREEBUSY" calendar user's component
used to publish busy time, event, to-do or journal).
This property is not 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 information.

3.6.5. Time Zone Component

Component Name: VTIMEZONE

Purpose: Provide a single
user's calendar.

Description: The property MUST only be specified within calendar
components to specify participants, non-participants and the chair grouping of component properties that defines a group scheduled calendar entity. The property is specified within
an "EMAIL" category of the "VALARM"
time zone.

Format Definition: A "VTIMEZONE" calendar component to specify an
email address that is to receive defined by the email type of iCalendar alarm.

The property parameter CN
following notation:

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

2*(

; 'tzid' is for the common required, but MUST NOT occur more
; than once

tzid /

; 'last-mod' and 'tzurl' are optional,
but MUST NOT occur more than once

last-mod / tzurl /

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; one of 'standardc' or displayable name
associated with the calendar address; ROLE, for the intended role
that the attendee will have in 'daylightc' MUST occur
; and each MAY occur more than once.

standardc / daylightc /

; the calendar component; PARTSTAT, for
the status of the attendee's participation; RSVP, for indicating
whether the favor of a 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 was delegated to; and DELEGATED-FROM, to
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 that points to the directory information corresponding to the
attendee. These property parameters can be specified on an
"ATTENDEE"

property in either a "VEVENT", "VTODO" or "VJOURNAL" calendar
component. They MUST not be specified in an "ATTENDEE" property in a
"VFREEBUSY" or "VALARM" calendar component. If the LANGUAGE property
parameter following is specified, the identified language applies to the CN
parameter.

A recipient delegated a request MUST inherit the RSVP optional,
; and ROLE values
from the attendee that delegated the request to them.

Multiple attendees can be specified by including multiple "ATTENDEE"
properties within the calendar component.

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

attendee MAY occur more than once

x-prop

)

"END" ":" "VTIMEZONE" CRLF

standardc = "ATTENDEE" attparam "BEGIN" ":" cal-address "STANDARD" CRLF

attparam

tzprop

"END" ":" "STANDARD" CRLF

daylightc = *( "BEGIN" ":" "DAYLIGHT" CRLF

tzprop

"END" ":" "DAYLIGHT" CRLF

tzprop = 3*(

; the following are optional, each REQUIRED,
; but MUST NOT occur more than once

(";" cutypeparam) / (";"memberparam) /
(";" roleparam) / (";" partstatparam) /
(";" rsvpparam) / (";" deltoparam) /
(";" delfromparam) / (";" sentbyparam) /
(";"cnparam)

dtstart / (";" dirparam) tzoffsetto /
(";" languageparam) tzoffsetfrom /

; the following is are optional,
; and MAY occur more than once

(";" xparam)

comment / rdate / rrule / tzname / x-prop

)

Example: The following are examples

Description: A time zone is unambiguously defined by the set of this property's use time
measurement rules determined by the governing body 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:janedoe@host1.com

The following is an example of this property used given
geographic area. These rules describe at a minimum the base
offset from UTC for specifying
multiple attendees the time zone, often referred to an event:

ORGANIZER:MAILTO:jsmith@host1.com
ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=TENTATIVE;CN=Henry Cabot
:MAILTO:hcabot@host2.com
ATTENDEE;ROLE=REQ-PARTICIPANT;DELEGATED-FROM=
"MAILTO:bob@host.com"
;PARTSTAT=ACCEPTED;CN=Jane Doe:MAILTO:jdoe@host1.com

The following is an example 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 this property with a URI daylight hours, often referred to the
directory information associated with the attendee:

ATTENDEE;CN=John Smith;DIR="ldap://host.com:6666/o=eDABC%
20Industries,c=3DUS??(cn=3DBJim%20Dolittle)":MAILTO:jimdo@
host1.com as Daylight
Saving Time. Some locations adjust their time by a fraction of an

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The following June 2006

hour. Standard Time 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;PARTSTAT=TENTATIVE;DELEGATED-FROM=
"MAILTO:iamboss@host2.com";CN=Henry Cabot:MAILTO:hcabot@
host2.com
ATTENDEE;ROLE=NON-PARTICIPANT;PARTSTAT=DELEGATED;DELEGATED-TO=
"MAILTO:hcabot@host2.com";CN=The Big Cheese:MAILTO:iamboss
@host2.com
ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=ACCEPTED;CN=Jane Doe
:MAILTO:jdoe@host1.com

Example: also known as Winter Time. Daylight
Saving Time is also known as Advanced Time, Summer Time, or Legal
Time in certain countries. The following is an example of this property's use when
another calendar user is acting on behalf of table shows the "Attendee":

ATTENDEE;SENT-BY=MAILTO:jan_doe@host1.com;CN=John Smith:MAILTO:
jsmith@host1.com

8.2.17.2. 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 can be specified changes
in time zone rules in effect for New York City starting from 1967.
Each line represents a "VEVENT", "VTODO",
"VJOURNAL" description or "VFREEBUSY" calendar component.

Description: rule for a particular
observance.

Effective Observance Rule

+-----------+-------------------------+--------+--------------+
| Date | (Date/Time) | Offset | Abbreviation |
+-----------+-------------------------+--------+--------------+
| 1967-* | last Sun 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 |
+-----------+-------------------------+--------+--------------+

Effective Observance Rule

Date (Date/Time) Offset Abbreviation

1967-* last Sun 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

Note: The property value consists specification of textual contact
information. An alternative representation a global time zone registry is not
addressed by this document and is left for future study.
However, implementers may find the property value
can also be specified that refers to Olson time zone database
[TZDB] a URI pointing to useful reference. It is an alternate
form, such as a vCard [RFC 2426], informal, public-domain
collection of time zone information, which is currently being
maintained by volunteer Internet participants, and is used in
several operating systems. This database contains current and
historical time zone information for the contact information. a wide variety of

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

contact = "CONTACT" contparam ":" text CRLF

contparam = *(
; June 2006

locations around the following are optional,
; but MUST NOT occur more than once

(";" altrepparam) / (";" languageparam) /

; globe; it provides a time zone identifier
for every unique time zone rule set in actual use since 1970,
with historical data going back to the following is optional,
; introduction of standard
time.

Interoperability between two calendaring and MAY occur more than once

(";" xparam)

)

Example: The following 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 of this property referencing
textual contact information:

CONTACT:Jim Dolittle\, ABC Industries\, +1-919-555-1234 unambiguous format. The following is an example specification
of current time zone information is integral to this property with an alternate
representation behavior.

If present, the "VTIMEZONE" calendar component defines the set of
Standard Time and Daylight Saving Time observances (or rules) for
a LDAP URI to particular time zone for 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 given interval of a MIME body part containing the contact
information, such as a vCard [RFC 2426] embedded in a [MIME-DIR]
content-type:

CONTACT;ALTREP="CID:part3.msg970930T083000SILVER@host.com":Jim
Dolittle\, ABC Industries\, +1-919-555-1234 time. The following is
"VTIMEZONE" calendar component cannot be nested within other
calendar components. Multiple "VTIMEZONE" calendar components can
exist in an example of iCalendar object. In this property referencing situation, each "VTIMEZONE"
MUST represent a network
resource, unique time zone definition. This is necessary
for some classes of events, such as a vCard [RFC 2426] object containing the contact
information:

CONTACT;ALTREP="http://host.com/pdi/jdoe.vcf":Jim
Dolittle\, ABC Industries\, +1-919-555-1234

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8.2.17.3. Organizer

Property Name: ORGANIZER

Purpose: airline flights, that start in
one time zone and end in another.

The property defines the organizer for a "VTIMEZONE" 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 component MUST be specified in an present if the
iCalendar object contains an RRULE that specifies generates dates on both
sides of a group scheduled calendar entity. This property MUST
be specified time zone shift (e.g., both in an Standard Time and
Daylight Saving Time) unless the iCalendar object that specifies the publication of intends to
convey a calendar user's busy time. This property MUST NOT floating time ( see Section 3.3.12 for proper
interpretation of floating time). It can be specified in
an present if the
iCalendar object that specifies only does not contain such a RRULE. In addition, if a
RRULE is present, there MUST be valid 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: information for
all recurrence instances.

The property is specified within the "VEVENT", "VTODO",
"VJOURNAL "VTIMEZONE" calendar components to specify component MUST include the organizer "TZID"
property and at least one definition of a group
scheduled calendar entity. standard or daylight
component. The property is specified within standard or daylight component MUST include the
"VFREEBUSY"
"DTSTART", "TZOFFSETFROM" and "TZOFFSETTO" properties.

An individual "VTIMEZONE" calendar component to specify MUST be specified for
each unique "TZID" parameter value specified in the iCalendar
object.

Each "VTIMEZONE" calendar user
requesting component consists of a collection of
one or more sub-components that describe the free rule for a particular
observance (either a Standard Time or busy time. When publishing a "VFREEBUSY"
calendar component, the property is used to specify the calendar Daylight Saving Time
observance). The "STANDARD" sub-component consists of a
collection of properties that
the published busy time came from. describe Standard Time. The property has
"DAYLIGHT" sub-component consists of a collection of properties
that describe Daylight Saving Time. In general this collection of
properties consists of:

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the property parameters CN, first onset date-time for specifying the
common or display name associated with observance

the "Organizer", DIR, last onset date-time for
specifying the observance, if a pointer last onset is
known.

the offset to be applied for the directory information associated with observance

a rule that describes the
"Organizer", SENT-BY, day and time when the observance
takes effect

an optional name for specifying another calendar user that is
acting on behalf of the "Organizer". The non-standard parameters observance

For a given time zone, there may
also be specified on this property. If the LANGUAGE property
parameter is specified, multiple unique definitions of
the identified language applies 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 CN
parameter value.

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Format Definition:
time zone for a given period of time. The property offset to apply at any
given time is defined found by locating the following notation:

organizer = "ORGANIZER" orgparam ":"
cal-address CRLF

orgparam = *(

; observance that has the following are optional,

; but MUST NOT occur more than once

(";" cnparam) / (";" dirparam) / (";" sentbyparam) /
(";" languageparam) /

; last
onset date and time before the following 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 optional,
; a text value that uniquely
identifies the VTIMEZONE; and each MAY occur more than once

(";" xparam)

)

Example: The following is an example once.
calendar component within the scope of this property:

ORGANIZER;CN=John Smith:MAILTO:jsmith@host1.com an iCalendar object.

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

The optional "TZURL" property with is a pointer url value that points 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 a
published VTIMEZONE definition. TZURL SHOULD refer to a resource
that is an example of this property used accessible by another calendar
user anyone who is acting on behalf of the organizer, with responses
intended to be sent back might need to interpret the organizer,
object. This SHOULD NOT normally be a "file" URL or other URL
that is not widely-accessible.

The collection of properties that are used to define the other calendar
user:

ORGANIZER;SENT-BY="MAILTO:jane_doe@host.com":
MAILTO:jsmith@host1.com

8.2.17.4. Participation Role

Parameter Name: ROLE

Purpose: To specify STANDARD
and DAYLIGHT sub-components include:

The mandatory "DTSTART" property gives the participation role effective onset date
and local time for the calendar user
specified by the property.

Description: This parameter can time zone sub-component definition.
"DTSTART" in this usage MUST be specified on properties with as a
CAL-ADDRESS value type. The parameter specifies the participation local DATE-TIME
value.

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role for the calendar user specified by the June 2006

The mandatory "TZOFFSETFROM" property gives the UTC offset which
is in use when the group
schedule calendar component. If not specified on a property that
allows onset of this parameter, the default value is REQ-PARTICIPANT.

Format Definition: The property parameter time zone observance begins.
"TZOFFSETFROM" is defined by combined with "DTSTART" to define the effective
onset for the time zone sub-component definition. For example,
the following
notation:

roleparam = "ROLE" "="
("CHAIR" ; Indicates chair represents the time at which the observance of
Standard Time took effect in Fall 1967 for New York City:

DTSTART:19671029T020000

TZOFFSETFROM:-0400

The mandatory "TZOFFSETTO " property gives the
; calendar entity
/ "REQ-PARTICIPANT" ; Indicates a participant whose
; participation is required
/ "OPT-PARTICIPANT" ; Indicates a participant whose
; participation UTC offset for the
time zone sub-component (Standard Time or Daylight Saving Time)
when this observance is in use.

The optional
/ "NON-PARTICIPANT" ; Indicates a participant who "TZNAME" property is
; copied the customary name for information
; purposes only
/ x-name ; Experimental role
/ iana-token) ; Other IANA role
; Default is REQ-PARTICIPANT

Example:

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

Figure 121

8.2.17.5. Sent By

Parameter Name: SENT-BY

Purpose: To specify the calendar user that is acting on behalf of the
calendar user time
zone. It may be specified by multiple times, to allow for specifying
multiple language variants of the property.

Description: time zone names. This parameter can could be specified on properties with a
CAL-ADDRESS value type. The parameter specifies
used for displaying dates.

If specified, the calendar user
that is acting on behalf of onset for the calendar user specified observance defined by the time
zone sub-component is defined by either the "RRULE" or "RDATE"
property. The parameter value MUST If neither is specified, only one sub-component can be a MAILTO URI as defined
specified in
[RFC 1738]. The individual the "VTIMEZONE" calendar address parameter values MUST
each be component and it is assumed
that the single observance specified is always in a quoted-string.

Format Definition: effect.

The "RRULE" property parameter is defined by defines the following
notation:

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

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Example:

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

Figure 123

8.2.17.6. Delegators

Parameter Name: DELEGATED-FROM

Purpose: To specify recurrence rule for the calendar users that have delegated their
participation to onset of
the calendar user specified observance defined by this time zone sub-component. Some
specific requirements for the property.

Description: This parameter can be specified on properties with a
CAL-ADDRESS value type. This usage of RRULE for this purpose
include:

If observance is known to have an effective end date, the
"UNTIL" recurrence rule parameter can MUST be specified on a
property that has a value type used to specify the
last valid onset of calendar address. This parameter
specifies those calendar uses that have delegated their participation
in a group scheduled event or to-do this observance (i.e., the UNTIL date-time
will be equal to the calendar user specified last instance generated by the property. The value MUST be a MAILTO URI as defined in [RFC
1738]. The individual calendar address parameter values recurrence
pattern). It MUST each be specified in a quoted-string.

Format Definition: UTC time.

The property parameter is defined by "DTSTART" and the following
notation:

delfromparam = "DELEGATED-FROM" "="
DQUOTE cal-address DQUOTE
*("," DQUOTE cal-address DQUOTE)

Example:

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

Figure 125

8.2.17.7. Delegatees

Parameter Name: DELEGATED-TO

Purpose: To specify "TZOFFSETTO" properties MUST be used when
generating the calendar users to whom onset date-time values (instances) from the calendar user
specified by
RRULE.

Alternatively, the "RDATE" property has delegated participation.

Description: This parameter can be specified on properties with a
CAL-ADDRESS value type. This parameter specifies those calendar
users whom have been delegated participation in a group scheduled
event or to-do by used to define the calendar user specified
onset of the observance by giving the property. The
value individual onset date and
times. "RDATE" in this usage MUST be a MAILTO URI specified as defined a local DATE-
TIME value in [RFC 1738]. The individual UTC time.

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calendar address parameter values MUST each be specified in a quoted-
string.

Format Definition: June 2006

The optional "COMMENT" property parameter is defined by the following
notation:

deltoparam = "DELEGATED-TO" "=" DQUOTE cal-address DQUOTE
*("," DQUOTE cal-address DQUOTE) also allowed for descriptive
explanatory text.

Example:

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

8.2.17.8. Common Name

Parameter Name: CN

Purpose: To specify the common name to be associated with The following are examples of the "VTIMEZONE" calendar user specified by the property.

Description:
component:

This parameter can be specified on properties with a
CAL-ADDRESS value type. The parameter specifies the common name to
be associated with the calendar user specified by is an example showing time zone information for the Eastern
United States using "RDATE" property. The
parameter value Note that this is text. The parameter value 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 display
text to be associated with the calendar address specified by the
property.

Format Definition: The property parameter a recurring event that occurs every
Friday, 8:00AM-9:00 AM, starting June 1, 1997, ending December 31,
1997.

This is defined by a simple example showing the following
notation:

cnparam = "CN" "=" param-value

Example:

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

8.2.18. Calendar User Type

Parameter Name: CUTYPE

Purpose: To specify current time zone rules for
the type Eastern United States using a RRULE recurrence pattern. Note
that there is no effective end date to either of calendar user specified by the
property.

Description: Standard Time
or Daylight Time rules. This parameter can information would be specified on properties with valid for a
CAL-ADDRESS value type. The parameter identifies the type
recurring event starting today and continuing indefinitely.

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BEGIN:VTIMEZONE
TZID:US-Eastern
LAST-MODIFIED:19870101T000000Z
TZURL:http://zones.example.com/tz/US-Eastern.ics
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 is an example showing a fictitious set of
calendar user specified by rules for the property. If not specified on a
property that allows this parameter,
Eastern United States, where the default Daylight Time rule has an
effective end date (i.e., after that date, Daylight Time is INDIVIDUAL. no
longer observed).

BEGIN:VTIMEZONE
TZID:US--Fictitious-Eastern
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

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This is an example showing a fictitious set of rules for the
Eastern United States, where the first Daylight Time rule has an
effective end date. There is a second Daylight Time rule that
picks up where the other left off.

BEGIN:VTIMEZONE
TZID:US--Fictitious-Eastern
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
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
END:DAYLIGHT
END:VTIMEZONE

3.6.6. Alarm Component

Component Name: VALARM

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

Format Definition: The property parameter A "VALARM" calendar component is defined by the
following notation:

cutypeparam

alarmc = "CUTYPE" "="
("INDIVIDUAL" ; An individual "BEGIN" ":" "VALARM" CRLF
(audioprop / "GROUP" ; A group of individuals dispprop / "RESOURCE" ; A physical resource emailprop / "ROOM" procprop)
"END" ":" "VALARM" CRLF

audioprop = 2*(

; A room resource
/ "UNKNOWN" 'action' and 'trigger' are both REQUIRED,

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; Otherwise not known but MUST NOT occur more than once

action / x-name ; Experimental type trigger / iana-token)

; Other IANA registered 'duration' and 'repeat' are both optional,
; type and MUST NOT occur more than once each,
; Default is INDIVIDUAL

Example:

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

8.2.19. Directory Entry Reference

Parameter Name: DIR

Purpose: To specify reference to a directory entry associated with but if one occurs, so MUST the calendar user specified by other

duration / repeat /

; the property.

Description: This parameter can be specified on properties with a
CAL-ADDRESS value type. The parameter specifies a reference to following is optional,
; but MUST NOT occur more than once

attach /

; the
directory entry associated with following is optional,
; and MAY occur more than once

x-prop

)

dispprop = 3*(

; the calendar user specified by following are all REQUIRED,
; but MUST NOT occur more than once

action / description / trigger /

; 'duration' and 'repeat' are both optional,
; and MUST NOT occur more than once each,
; but if one occurs, so MUST the
property. The parameter value other

duration / repeat /

; the following is a URI. The individual URI
parameter values optional,
; and MAY occur more than once

x-prop

)

emailprop = 5*(

; the following are all REQUIRED,
; but MUST each be specified in a quoted-string.

Format Definition: The property parameter NOT occur more than once

action / description / trigger / summary /

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; the following is defined by REQUIRED,
; and MAY occur more than once

attendee /

; 'duration' and 'repeat' are both optional,
; and MUST NOT occur more than once each,
; but if one occurs, so MUST the other

duration / repeat /

; the following
notation:

dirparam are optional,
; and MAY occur more than once

attach / x-prop

)

procprop = "DIR" "=" DQUOTE uri DQUOTE

Example:

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

8.2.20. Recurrence ID

Property Name: RECURRENCE-ID

Purpose: This property 3*(

; the following are all REQUIRED,
; but MUST NOT occur more than once

action / attach / trigger /

; 'duration' and 'repeat' are both optional,
; and MUST NOT occur more than once each,
; but if one occurs, so MUST the other

duration / repeat /

; 'description' is used in conjunction with optional,
; and MUST NOT occur more than once

description /

; the "UID" following is optional,
; and
"SEQUENCE" property to identify MAY occur more than once

x-prop

)

Description: A "VALARM" calendar component is a specific instance grouping of component
properties that is a recurring
"VEVENT", "VTODO" reminder or "VJOURNAL" calendar component. The property 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.

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value is the effective value of the "DTSTART" property of June 2006

The "VALARM" calendar component MUST include the
recurrence instance.

Value Type: "ACTION" and
"TRIGGER" properties. The default value type for this "ACTION" property is DATE-TIME.
The time format can be any of further constrains
the valid forms defined for a DATE-TIME
value type. See DATE-TIME value type definition for specific
interpretations of "VALARM" calendar component in the various forms. The value type following ways:

When the action is "AUDIO", the alarm can be set to
DATE.

Property Parameters: Non-standard property, value data type, time
zone identifier also include one and recurrence identifier range parameters can be
specified on this property.

Conformance: This property can be specified in an iCalendar object
containing a recurring calendar component.

Description: The full range of calendar components specified by
only one "ATTACH" property, which MUST point to a
recurrence set sound resource,
which is referenced by referring to just rendered when the "UID" property
value corresponding to alarm is triggered.

When the calendar component. The "RECURRENCE-ID"
property allows action is "DISPLAY", the reference to an individual instance within alarm MUST also include a
"DESCRIPTION" property, which contains the
recurrence set.

If text to be displayed
when the value of alarm is triggered.

When the "DTSTART" property action is a DATE type value, then "EMAIL", the
value alarm MUST include a "DESCRIPTION"
property, which contains the text to be used as the calendar date for message body,
a "SUMMARY" property, which contains the recurrence instance.

The date/time value is set text to be used as the time when the original recurrence
instance would occur; meaning that if
message subject, and one or more "ATTENDEE" properties, which
contain the intent is email address of attendees to change a
Friday meeting receive the message. It
can also include one or more "ATTACH" properties, which are
intended to Thursday, be sent as message attachments. When the date/time alarm is still set to
triggered, the
original Friday meeting.

The "RECURRENCE-ID" property email message is used in conjunction with sent.

When the "UID" action is "PROCEDURE", the alarm MUST include one and "SEQUENCE" property
only one "ATTACH" property, which MUST point 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 procedure
resource, which is fixed. When the definition of invoked when the recurrence
set alarm is triggered.

The "VALARM" calendar component MUST only appear within either a
"VEVENT" or "VTODO" calendar component. "VALARM" calendar
components cannot be nested. Multiple mutually independent
"VALARM" calendar components can be specified for a single
"VEVENT" or "VTODO" calendar component changes, and hence the "SEQUENCE" component.

The "TRIGGER" property value changes, specifies when the "RECURRENCE-ID" for alarm will be triggered.
The "TRIGGER" property specifies a given recurrence
instance might also change.The "RANGE" parameter is used duration prior to specify the effective range start of recurrence instances from
an event or a to-do. The "TRIGGER" edge may be explicitly set to
be relative to the instance
specified by "START" or "END" of the "RECURRENCE-ID" property value. The default value
for event or to-do with the range
"RELATED" parameter is of the single recurrence instance only. "TRIGGER" property. The "TRIGGER"
property value type can also alternatively be "THISANDPRIOR" set to indicate a range defined by the
given recurrence instance an absolute
calendar date and all prior instances time of day value.

In an alarm set to trigger on the "START" of an event or to-do,
the value can "DTSTART" property MUST be
"THISANDFUTURE" to indicate present in the associated event or
to-do. In an alarm in a range defined by "VEVENT" calendar component set to
trigger on the given recurrence
instance "END" of the event, either the "DTEND" property
MUST be present, or the "DTSTART" and all subsequent instances. "DURATION" properties MUST
both be present. In an alarm in a "VTODO" calendar component set
to trigger on the "END" of the to-do, either the "DUE" property
MUST be present, or the "DTSTART" and "DURATION" properties MUST
both be present.

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Format Definition: June 2006

The property is alarm can be defined by the following notation:

recurid = "RECURRENCE-ID" ridparam ":" ridval CRLF

ridparam = *(

; the following are optional,
; but such that it triggers repeatedly. A
definition of an alarm with a repeating trigger MUST NOT occur more than once

(";" "VALUE" "=" ("DATE-TIME" / "DATE)) /
(";" tzidparam) / (";" rangeparam) /
; include both
the following is optional,
; "DURATION" and MAY occur more than once

(";" xparam)

)

ridval = date-time / date
;Value MUST match value type

Example: The following are examples of this property:

RECURRENCE-ID;VALUE=DATE:19960401

RECURRENCE-ID;RANGE=THISANDFUTURE:19960120T120000Z

Figure 135

8.2.21. Related To

Property Name: RELATED-TO

Purpose: "REPEAT" properties. The "DURATION" property is used to represent a relationship or
reference between one calendar component and another.

Value Type: TEXT

Property Parameters: Non-standard and relationship type property
parameters can be specified on this property.

Conformance:
specifies the delay period, after which the alarm will repeat.
The "REPEAT" property can specifies the number of additional
repetitions that the alarm will be specified one or more times triggered. This repetition
count is in addition to the
"VEVENT", "VTODO" or "VJOURNAL" calendar components.

Description: The property value consists initial triggering of the persistent, globally
unique identifier alarm. Both
of another calendar component. This value would these properties MUST be
represented present in a calendar component by the "UID" property.

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By default, the property value points order to another calendar component
that has specify a PARENT relationship to
repeating alarm. If one of these two properties is absent, then
the referencing object. alarm will not repeat beyond the initial trigger.

The
"RELTYPE" "ACTION" property parameter is used to either explicitly state the
default PARENT relationship type to within the referenced "VALARM" calendar
component
or to override specify the default PARENT relationship type and specify
either a CHILD or SIBLING relationship. The PARENT relationship
indicates that of action invoked when the calendar component alarm is
triggered. The "VALARM" properties provide enough information for
a subordinate specific action to be invoked. It is typically the
responsibility of a "Calendar User Agent" (CUA) to deliver the
referenced calendar component. The CHILD relationship indicates that
alarm in the calendar component is a superior specified fashion. An "ACTION" property value of the referenced calendar
component. The SIBLING relationship indicates
AUDIO specifies an alarm that causes a sound to be played to alert
the calendar
component is user; DISPLAY specifies an alarm that causes a peer of text message to
be displayed to the referenced calendar component.

Changes user; EMAIL specifies an alarm that causes an
electronic email message to be delivered to one or more email
addresses; and PROCEDURE specifies an alarm that causes a calendar component referenced by this
procedure to be executed. The "ACTION" property can have MUST specify one
and only one of these values.

In an implicit impact on the related calendar component. For example, AUDIO alarm, 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 optional "ATTACH" property is included,
it MUST specify an implied impact to audio sound resource. The intention is that
the related CHILD calendar components. This sound will be played as the alarm effect. If an "ATTACH"
property is intended
only specified that does not refer to provide information on a sound resource, or
if the relationship of calendar
components. It specified sound resource cannot be rendered (because its
format is up to unsupported, or because it cannot be retrieved), then
the target calendar system to maintain any
property implications of this relationship.

Format Definition: The property is defined by CUA or other entity responsible for playing the following notation:

related = "RELATED-TO" [relparam] ":" text CRLF

relparam = *(

; 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 following intended alarm effect is optional,
; but MUST NOT occur more than once

(";" reltypeparam) /

; for the following is optional,
; and MAY occur more than once

(";" xparm)

)

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The following is an example text
value of this property:

RELATED-TO:jsmith.part7.19960817T083000.xyzMail@host3.com

RELATED-TO:19960401-080045-4000F192713-0052@host1.com

Figure 137

8.2.22. Uniform Resource Locator

Property Name: URL

Purpose: This property defines a Uniform Resource Locator (URL)
associated with the iCalendar object.

Value Type: URI

Property Parameters: Non-standard "DESCRIPTION" property parameters can to be
specified on this property.

Conformance: This property can displayed to the user.

In an EMAIL alarm, the intended alarm effect is for an email
message to be composed and delivered to all the addresses
specified once by the "ATTENDEE" properties in the "VEVENT",
"VTODO", "VJOURNAL" or "VFREEBUSY" "VALARM" calendar components.

Description: This
component. The "DESCRIPTION" property may be used in a calendar component to
convey a location where a more dynamic rendition of the calendar
information associated with the "VALARM" calendar
component can MUST be found.
This memo does not attempt to standardize the form of the URI, nor used as the format body text of the resource pointed to by the property value. If message, and the
URL
"SUMMARY" property and Content-Location MIME header are both specified,
they MUST point to be used as the same resource.

Format Definition: The property is defined by subject text. Any "ATTACH"
properties in the following notation:

url = "URL" urlparam ":" uri CRLF

urlparam = *(";" xparam)

Example: The following is an example of this property:

URL:http://abc.com/pub/calendars/jsmith/mytime.ics

Figure 139

8.2.23. Unique Identifier

Property Name: UID

Purpose: This property defines "VALARM" calendar component SHOULD be sent as
attachments to the persistent, globally unique message.

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identifier for June 2006

In a PROCEDURE alarm, the calendar component.

Value Type: TEXT

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: The "ATTACH" property MUST be specified in the "VEVENT", "VTODO",
"VJOURNAL" or "VFREEBUSY" "VALARM"
calendar components.

Description: The UID itself component MUST be specify a globally unique identifier.
The generator of the identifier MUST guarantee that the identifier is
unique. There are several algorithms procedure or program that can be used to accomplish
this. The identifier is RECOMMENDED
intended to be invoked as the identical syntax to alarm effect. If the [RFC 822] addr-spec. A good method to assure uniqueness is to
put the domain name procedure 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
program is in as a DATE-TIME value) along
with some other currently unique (perhaps sequential) identifier
available on format that cannot be rendered, then no procedure
alarm will be invoked. If the system (for example, a process id number). Using a
date/time "DESCRIPTION" property is present,
its value on the left hand side and a domain name or domain
literal on specifies the right hand side makes it possible argument string to guarantee
uniqueness since no two hosts should be using passed to the same domain name
procedure or
IP address at the same time. Though other algorithms will work, it
is RECOMMENDED program. "Calendar User Agents" that the right hand side contain some domain
identifier (either receive an
iCalendar object with this category of the host itself alarm, can disable or otherwise) such that allow
the
generator "Calendar User" to disable, or otherwise ignore this type of
alarm. While a very useful alarm capability, the message identifier can guarantee the uniqueness PROCEDURE type
of alarm SHOULD be treated by the left hand side within the scope of that domain.

This "Calendar User Agent" as a
potential security risk.

Example: The following example is the method for correlating scheduling messages with the
referenced "VEVENT", "VTODO", or "VJOURNAL" a "VALARM" calendar component. 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;FMTTYPE=audio/basic:ftp://host.com/pub/sounds/bell-01.aud
END:VALARM

The full range of following example is for a "VALARM" calendar components specified by component that
specifies a recurrence set
is referenced by referring to just display alarm that will trigger 30 minutes before the "UID" property value
corresponding to
scheduled start of the calendar component. The "RECURRENCE-ID"
property allows event or the reference to an individual instance within due date/time of the
recurrence set.

This property to-do it
is an important method for group scheduling
applications to match requests associated with later replies, modifications or
deletion requests. Calendaring and scheduling applications MUST
generate this property in "VEVENT", "VTODO" and "VJOURNAL" calendar
components to assure interoperability will repeat 2 more times at 15 minute
intervals:

BEGIN:VALARM
TRIGGER:-PT30M
REPEAT:2
DURATION:PT15M
ACTION:DISPLAY
DESCRIPTION:Breakfast meeting with other group scheduling
applications. This identifier executive\n
team at 8:30 AM EST.
END:VALARM

The following example is created by the for a "VALARM" calendar system component that
generates
specifies an iCalendar object.

Implementations MUST be able to receive and persist values email alarm that will trigger 2 days before the
scheduled due date/time of at a to-do it is associated with. It does
not repeat. The email has a subject, body and attachment link.

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least 255 characters for this property.

Format Definition: The property June 2006

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 attendees
to the weekly managers meeting (MGR-LIST). Attached is defined by a
pointer the following notation:

uid = "UID" uidparam ":" text CRLF

uidparam = *(";" xparam)

Example: document template for the agenda file.
ATTACH;FMTTYPE=application/msword:http://host.com/templates/agen
da.doc
END:VALARM

The following is an example of this property:

UID:19960401T080045Z-4000F192713-0052@host1.com

Figure 141

8.2.24. Relationship Type

Parameter is 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 procedure file.

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

3.7. Calendar Properties

The Calendar Properties are attributes that apply to the iCalendar
object, as a whole. These properties do not appear within a calendar
component. They SHOULD be specified after the "BEGIN:VCALENDAR"
delimiter string and prior to any calendar component.

3.7.1. Calendar Scale

Property Name: RELTYPE CALSCALE

Purpose: To specify This property defines the type of hierarchical relationship associated
with calendar scale used for the
calendar component information specified by in the property.

Description: This parameter iCalendar object.

Value Type: TEXT

Property Parameters: Non-standard property parameters can be
specified on a property that
references another related calendar. The parameter specifies the
hierarchical relationship type of the calendar component referenced
by the this property. The parameter value

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Conformance: Property can be PARENT, to indicate that
the referenced calendar component specified in an iCalendar object. The
default value is a superior of calendar
component; CHILD to indicate that the referenced calendar component "GREGORIAN".

Description: This memo is a subordinate of based on the Gregorian calendar component; SIBLING to indicate that
the referenced scale. The
Gregorian calendar component scale is a peer of the calendar
component. If assumed if this parameter property is not
specified on an allowable
property, in the default relationship type iCalendar object. It is PARENT. expected that other
calendar scales will be defined in other specifications or by
future versions of this memo.

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

reltypeparam

calscale = "RELTYPE" "="
("PARENT" ; Parent relationship. Default.
/ "CHILD" ; Child relationship
/ "SIBLING ; Sibling relationship "CALSCALE" calparam ":" calvalue CRLF

calparam = *(";" xparam)

calvalue = "GREGORIAN" / iana-token ; Some other IANA registered
; iCalendar relationship type
/ x-name) ; A non-standard, experimental
; relationship type

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Example:

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

Figure 143

8.3. Recurrence Component Properties The following properties specify recurrence information in calendar
components.

8.3.1. Exception Date/Times is an example of this property:

CALSCALE:GREGORIAN

3.7.2. Method

Property Name: EXDATE METHOD

Purpose: This property defines the list of date/time exceptions for a
recurring iCalendar object method associated
with the calendar component. object.

Value Type: The default value type for this property is DATE-TIME.
The value type can be set to DATE. TEXT

Property Parameters: Non-standard, value data type and time zone
identifier Non-standard property parameters can be
specified on this property.

Conformance: This The property can be specified in an iCalendar object
that includes a recurring calendar component. object.

Description: The exception dates, if specified, are When used in computing
the recurrence set. The recurrence set is the complete set of
recurrence instances for a calendar component. The recurrence set is
generated by considering MIME message entity, the initial "DTSTART" value of this
property along with MUST be the "RRULE", "RDATE", "EXDATE" and "EXRULE" properties contained same as the Content-Type "method" parameter
value. This property can only appear once within the iCalendar
object. The "DTSTART" property defines If either the
first instance in "METHOD" property or the recurrence set. Multiple instances of Content-Type
"method" parameter is specified, then the
"RRULE" and "EXRULE" properties can other MUST also be specified to define more
sophisticated recurrence sets. The final recurrence set is generated
specified.

No methods are defined by gathering all of this specification. This is the start date-times generated by any subject
of other specifications, such as the
specified "RRULE" and "RDATE" properties, and then excluding any
start date and times which fall within the union of start date and
times generated by any specified "EXRULE" and "EXDATE" properties.
This implies that start date and times within exclusion related
properties (i.e., "EXDATE" and "EXRULE") take precedence over those
specified by inclusion properties (i.e., "RDATE" and "RRULE"). Where
duplicate instances are generated iCalendar Transport-
independent Interoperability Protocol (iTIP) defined by the "RRULE" and "RDATE"
properties, only one recurrence is considered. Duplicate instances [I-D.ietf-
calsify-2446bis].

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are ignored.

The "EXDATE" June 2006

If this property can be used to exclude the value specified in
"DTSTART". However, is not present in such cases the original "DTSTART" date iCalendar object, then a
scheduling transaction MUST
still NOT be maintained by the calendaring and scheduling system because
the original "DTSTART" value has inherent usage dependencies by other
properties assumed. In such as cases, the "RECURRENCE-ID".
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:

exdate

method = "EXDATE" exdtparam "METHOD" metparam ":" exdtval *("," exdtval) metvalue CRLF

exdtparam

metparam = *(

; the following are optional,
; but MUST NOT occur more than once

(";" "VALUE" "=" ("DATE-TIME" / "DATE")) /

(";" tzidparam) /

; the following is optional,
; and MAY occur more than once

(";" *(";" xparam)

)

exdtval

metvalue = date-time / date
;Value MUST match value type iana-token

Example: The following is an a hypothetical example of this property:

EXDATE:19960402T010000Z,19960403T010000Z,19960404T010000Z

Figure 145

8.3.2. Exception Rule property to
convey that the iCalendar object is a request for a meeting:

METHOD:REQUEST

3.7.3. Product Identifier

Property Name: EXRULE PRODID

Purpose: This property defines a rule or repeating pattern specifies the identifier for an
exception to a recurrence set. the product that
created the iCalendar object.

Value Type: RECUR TEXT

Property Parameters: Non-standard property parameters can be

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specified on this property.

Conformance: This The property can MUST be specified once in "VEVENT", "VTODO" or
"VJOURNAL" calendar components. an iCalendar
object.

Description: The exception rule, if specified, is used in computing vendor of the recurrence set. The recurrence set implementation SHOULD assure that this
is the complete set of
recurrence instances for a calendar component. The recurrence set is
generated by considering the initial "DTSTART" globally unique identifier; using some technique such as an
FPI value, as defined in [ISO.9070.1991].

This property along with
the "RRULE", "RDATE", "EXDATE" and "EXRULE" properties contained
within SHOULD not be used to alter the interpretation of an
iCalendar object. The "DTSTART" defines object beyond the first
instance semantics specified in the recurrence set. Multiple instances of the "RRULE"
and "EXRULE" properties can also this memo. For
example, it is not to be specified used to define more
sophisticated recurrence sets. further the understanding of non-
standard properties.

Format Definition: The final recurrence set property is generated defined by gathering all of the start date-times generated by any of following notation:

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prodid = "PRODID" pidparam ":" pidvalue CRLF

pidparam = *(";" xparam)

pidvalue = text
;Any text that describes the
specified "RRULE" and "RDATE" properties, product and excluding any start
date and times which fall within the union version
;and that is generally assured of start date and times
generated by any specified "EXRULE" and "EXDATE" properties. This
implies being unique.

Example: The following is an example of this property. It does not
imply that start date and times within exclusion related properties
(i.e., "EXDATE" and "EXRULE") take precedence over those specified by
inclusion

properties (i.e., "RDATE" and "RRULE"). Where duplicate instances
are generated by English is the "RRULE" default language.

PRODID:-//ABC Corporation//NONSGML My Product//EN

3.7.4. Version

Property Name: VERSION

Purpose: This property specifies the identifier corresponding to the
highest version number or the minimum and "RDATE" properties, only one
recurrence maximum range of the
iCalendar specification that is considered. Duplicate instances are ignored.

The "EXRULE" required in order to interpret the
iCalendar object.

Value Type: TEXT

Property Parameters: Non-standard property parameters can be used to exclude the value
specified in
"DTSTART". However, in such cases the original "DTSTART" date on this property.

Conformance: This property MUST
still be maintained specified by the calendaring and scheduling system because
the original "DTSTART" an iCalendar object,
but MUST only be specified once.

Description: A value has inherent usage dependencies by other
properties such as the "RECURRENCE-ID". of "2.0" corresponds to this memo.

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

exrule

version = "EXRULE" exrparam "VERSION" verparam ":" recur vervalue CRLF

exrparam

verparam = *(";" xparam)

Example: The following are examples of this property. Except every
other week, on Tuesday and Thursday for 4 occurrences:

EXRULE:FREQ=WEEKLY;COUNT=4;INTERVAL=2;BYDAY=TU,TH

Figure 147

vervalue = "2.0" ;This memo
/ maxver
/ (minver ";" 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

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Except daily for 10 occurrences:

EXRULE:FREQ=DAILY;COUNT=10

Except yearly in June and July for 8 occurrences:

EXRULE:FREQ=YEARLY;COUNT=8;BYMONTH=6,7

8.3.3. Recurrence Date/Times 2006

Example: The following is an example of this property:

VERSION:2.0

3.8. Component Properties

The following properties can appear within calendar components, as
specified by each component property definition.

3.8.1. Descriptive Component Properties

The following properties specify descriptive information about
calendar components.

3.8.1.1. Attachment

Property Name: RDATE ATTACH

Purpose: This The property defines provides the list of date/times for capability to associate a
recurrence set. document
object with a calendar component.

Value Type: The default value type for this property is DATE-TIME. URI. The
value type can also be set to DATE or PERIOD. BINARY to indicate inline binary
encoded content information.

Property Parameters: Non-standard, inline encoding, format type and
value data type and time zone
identifier property parameters can be specified on this
property.

Conformance: The property can be specified in a "VEVENT", "VTODO",
"VJOURNAL" or "VTIMEZONE" "VALARM" calendar components.

Description: This The property can appear along with the "RRULE" be specified within "VEVENT", "VTODO",
"VJOURNAL", or "VALARM" calendar components. This property
to define an aggregate set of repeating occurrences. When they both
appear in can be
specified multiple times within an iCalendar object, the recurring events are object.

Format Definition: The property is defined by the union of occurrences defined by both following notation:

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attach = "ATTACH" attparam ":" uri CRLF

attach =/ "ATTACH" attparam ";" "ENCODING" "=" "BASE64"
";" "VALUE" "=" "BINARY" ":" binary

attparam = *(

; the "RDATE" following is optional,
; but MUST NOT occur more than once

(";" fmttypeparam) /

; the following is optional,
; and "RRULE". MAY occur more than once

(";" xparam)

)

Example: The recurrence dates, if specified, following are used in computing the
recurrence set. The recurrence set is the complete set examples of recurrence
instances this property:

ATTACH:CID:jsmith.part3.960817T083000.xyzMail@host1.com

ATTACH;FMTTYPE=application/postscript:ftp://xyzCorp.com/pub/
reports/r-960812.ps

3.8.1.2. Categories

Property Name: CATEGORIES

Purpose: This property defines the categories for a calendar
component. The recurrence set is generated
by considering the initial "DTSTART" property along with the "RRULE",
"RDATE", "EXDATE"

Value Type: TEXT

Property Parameters: Non-standard and "EXRULE" properties contained within the
iCalendar object. The "DTSTART" language property defines the first instance
in the recurrence set. Multiple instances of the "RRULE" and
"EXRULE" properties parameters
can also be specified to define more
sophisticated recurrence sets. on this property.

Conformance: The final recurrence set property can be specified within "VEVENT", "VTODO"
or "VJOURNAL" calendar components.

Description: This property is generated
by gathering all used to specify categories or subtypes
of the start date/times generated by any calendar component. The categories are useful in searching
for a calendar component of the
specified "RRULE" and "RDATE" properties, a particular type and excluding any start
date/times which fall within category.
Within the union of start date/times generated
by any specified "EXRULE" and "EXDATE" properties. This implies that
start date/times within exclusion related properties (i.e., "EXDATE"
and "EXRULE") take precedence over those "VEVENT", "VTODO" or "VJOURNAL" calendar components,
more than one category can be specified by inclusion
properties (i.e., "RDATE" and "RRULE"). Where duplicate instances
are generated as a list of categories
separated by the "RRULE" and "RDATE" properties, only one
recurrence is considered. Duplicate instances are ignored. COMMA character (US-ASCII decimal 44).

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

rdate

categories = "RDATE" rdtparam "CATEGORIES" catparam ":" rdtval text *("," rdtval) text)
CRLF

rdtparam

catparam = *(

; the following are is optional,
; but MUST NOT occur more than once

(";" "VALUE" "=" ("DATE-TIME" / "DATE" / "PERIOD")) /
(";" tzidparam) languageparam ) /

; the following is optional,
; and MAY occur more than once

(";" xparam)

)

rdtval = date-time / date / period
;Value MUST match value type

Example: The following are examples of this property:

RDATE:19970714T123000Z

RDATE;TZID=US-EASTERN:19970714T083000

RDATE;VALUE=PERIOD:19960403T020000Z/19960403T040000Z,
19960404T010000Z/PT3H

RDATE;VALUE=DATE:19970101,19970120,19970217,19970421
19970526,19970704,19970901,19971014,19971128,19971129,19971225

Figure 151

8.3.4. Recurrence Identifier Range

Parameter

CATEGORIES:APPOINTMENT,EDUCATION

CATEGORIES:MEETING

3.8.1.3. Classification

Property Name: RANGE CLASS

Purpose: To specify the effective range of recurrence instances from
the instance specified by This property defines the recurrence identifier access classification for a
calendar component.

Value Type: TEXT

Property Parameters: Non-standard property parameters can be
specified by the on this property.

Description:

Conformance: The parameter property can be specified on once in a property that
specifies "VEVENT",
"VTODO" or "VJOURNAL" calendar components.

Description: An access classification is only one component of the
general security system within a recurrence identifier. The parameter specifies calendar application. It
provides a method of capturing the
effective range scope of recurrence instances that the access the
calendar owner intends for information within an individual
calendar entry. The access classification of an individual
iCalendar component is specified by useful when measured along with the other
security components of a calendar system (e.g., calendar user
authentication, authorization, access rights, access role, etc.).

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property. The effective range is from the recurrence identified
specified by the property. If this parameter is not specified an
allowed property, then the default range is the single instance
specified by June 2006

Hence, the recurrence identifier value semantics of the property. The
parameter value can individual access classifications
cannot be "THISANDPRIOR" to indicate a range completely defined by this memo alone. Additionally,
due to the recurrence identified value "blind" nature of the property and all prior
instances. The parameter value can also be "THISANDFUTURE" to
indicate most exchange processes using this
memo, these access classifications cannot serve as an enforcement
statement for a range system receiving an iCalendar object. Rather,
they provide a method for capturing the intention of the calendar
owner for the access to the calendar component.

Format Definition: The property is defined by the recurrence identifier 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

3.8.1.4. Comment

Property Name: COMMENT

Purpose: This property specifies non-processing information intended
to provide a comment to the calendar user.

Value Type: TEXT

Property Parameters: Non-standard, alternate text representation and all
subsequent instances.
language property parameters can be specified on this property.

Conformance: This property can be specified in "VEVENT", "VTODO",
"VJOURNAL", "VTIMEZONE" or "VFREEBUSY" calendar components.

Description: The property can be specified multiple times.

Format Definition: The property parameter is defined by the following

rangeparam notation:

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comment = "RANGE" "=" ("THISANDPRIOR" "COMMENT" commparam ":" text CRLF

commparam = *(

; To specify all instances prior to the recurrence identifier following are optional,
; but MUST NOT occur more than once

(";" altrepparam) / (";" languageparam) / "THISANDFUTURE")

; To specify the instance specified by the recurrence identifier following is optional,
; and all subsequent recurrence instances MAY occur more than once

(";" xparam)

)

Example:

RECURRENCE-ID;RANGE=THISANDPRIOR:19980401T133000Z

Figure 153

8.3.5. Recurrence Rule 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

3.8.1.5. Description

Property Name: RRULE DESCRIPTION

Purpose: This property defines provides a rule or repeating pattern for
recurring events, to-dos, or time zone definitions. more complete description of the
calendar component, than that provided by the "SUMMARY" property.

Value Type: RECUR TEXT

Property Parameters: Non-standard Non-standard, alternate text representation and
language property parameters can be specified on this property.

Conformance: This The property can be specified one or more times in
recurring the "VEVENT", "VTODO" and "VTODO",
"VJOURNAL" or "VALARM" calendar components. It The property can also be
specified once in each STANDARD or DAYLIGHT sub-component
of the "VTIMEZONE" multiple times only within a "VJOURNAL" calendar
component.

Description: The recurrence rule, if specified, This property is used in computing
the recurrence set. The recurrence set is the complete set of
recurrence instances for a calendar component. The recurrence set is
generated by considering the initial "DTSTART" property along with the "RRULE", "RDATE", "EXDATE" "VEVENT" and "EXRULE" properties contained
within "VTODO" to
capture lengthy textual decriptions associated with the iCalendar object. The "DTSTART" activity.

This property defines the
first instance is used in the recurrence set. Multiple instances of the "VJOURNAL" calendar component to
capture one more textual journal entries.

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"RRULE" and "EXRULE" properties can also be specified to define more
sophisticated recurrence sets. The final recurrence set June 2006

This property is generated
by gathering all of used in the start date/times generated by any "VALARM" calendar component to
capture the display text for a DISPLAY category of alarm, to
capture the
specified "RRULE" and "RDATE" properties, body text for an EMAIL category of alarm and excluding any start
date/times which fall within to
capture the union of start date/times generated
by any specified "EXRULE" and "EXDATE" properties. This implies that
start date/times within exclusion related properties (i.e., "EXDATE"
and "EXRULE") take precedence over those specified argument string for a PROCEDURE category of alarm.

Format Definition: The property is defined by inclusion
properties (i.e., "RDATE" and "RRULE"). Where duplicate instances the following notation:

description = "DESCRIPTION" descparam ":" text CRLF

descparam = *(

; the following are generated by optional,
; but MUST NOT occur more than once

(";" altrepparam) / (";" languageparam) /

; the "RRULE" following is optional,
; and "RDATE" properties, only one
recurrence MAY occur more than once

(";" xparam)

)

Example: The following is considered. Duplicate instances are ignored. an example 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.

The "DTSTART" and "DTEND" following is an example of the property pair or "DTSTART" and "DURATION" with folding of long
lines:

DESCRIPTION:Last draft of the new novel is to be completed
for the editor's proof today.

3.8.1.6. Geographic Position

Property Name: GEO

Purpose: This property pair, specified within specifies information related to the global
position for the activity specified by a calendar component.

Value Type: FLOAT. The value MUST be two SEMICOLON separated FLOAT
values.

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Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This property can be specified in "VEVENT" or "VTODO"
calendar components.

Description: The property value specifies latitude and longitude, in
that order (i.e., "LAT LON" ordering). The longitude represents
the
first instance location east or west of the recurrence. When used with prime meridian as a recurrence rule,
the "DTSTART" positive or
negative real number, respectively. The longitude and "DTEND" properties MUST latitude
values MAY be specified in local time up to six decimal places, which will allow
for accuracy to within one meter of geographical position.
Receiving applications MUST accept values of this precision and
MAY truncate values of greater precision.

Values for latitude and longitude shall be expressed as decimal
fractions of degrees. Whole degrees of latitude shall be
represented by a two-digit decimal number ranging from 0 through
90. Whole degrees of longitude shall be represented by a decimal
number ranging from 0 through 180. When a decimal fraction of a
degree is specified, it shall be separated from the appropriate set whole number
of "VTIMEZONE" calendar components MUST degrees by a decimal point.

Latitudes north of the equator shall be
included. For detail on specified by a plus sign
(+), or by the usage absence of a minus sign (-), preceding the "VTIMEZONE" calendar
component, see digits
designating degrees. Latitudes south of the "VTIMEZONE" calendar component definition.

Any duration associated with Equator shall be
designated by a minus sign (-) preceding the iCalendar object applies digits designating
degrees. A point on the Equator shall be assigned to all
members the Northern
Hemisphere.

Longitudes east of the generated recurrence set. Any modified duration for
specific recurrences MUST prime meridian shall be explicitly specified using the "RDATE"
property.

Format Definition: This property is defined by a plus
sign (+), or by the following
notation:

rrule = "RRULE" rrulparam ":" recur CRLF

rrulparam = *(";" xparam)

Example: All examples assume absence of a minus sign (-), preceding the Eastern United States time zone.

Daily for 10 occurrences:

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=DAILY;COUNT=10

==> (1997 9:00 AM EDT)September 2-11

Daily until December 24, 1997:

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=DAILY;UNTIL=19971224T000000Z

==> (1997 9:00 AM EDT)September 2-30;October 1-25

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(1997 9:00 AM EST)October 26-31;November 1-30;December 1-23

Every other day - forever:

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=DAILY;INTERVAL=2
==> (1997 9:00 AM EDT)September2,4,6,8...24,26,28,30;
October 2,4,6...20,22,24
(1997 9:00 AM EST)October 26,28,30;November
1,3,5,7...25,27,29; Dec 1,3,...

Every 10 days, 5 occurrences:

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=DAILY;INTERVAL=10;COUNT=5

==> (1997 9:00 AM EDT)September 2,12,22;
October 2,12

Everyday in January, for 3 years:

DTSTART;TZID=US-Eastern:19980101T090000
RRULE:FREQ=YEARLY;UNTIL=20000131T090000Z;
BYMONTH=1;BYDAY=SU,MO,TU,WE,TH,FR,SA
or
RRULE:FREQ=DAILY;UNTIL=20000131T090000Z;
BYMONTH=1

==> (1998 9:00 AM EDT)January 1-31
(1999 9:00 AM EDT)January 1-31
(2000 9:00 AM EDT)January 1-31

Weekly for 10 occurrences

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=WEEKLY;COUNT=10

==> (1997 9:00 AM EDT)September 2,9,16,23,30;
October 7,14,21
(1997 9:00 AM EST)October 28;November 4

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Weekly until December 24, 1997

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=WEEKLY;UNTIL=19971224T000000Z

==> (1997 9:00 AM EDT)September 2,9,16,23,30;
October 7,14,21(1997 9:00 AM EST)October 28;
November 4,11,18,25;
December 2,9,16,23

Every other week - forever:

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=WEEKLY;INTERVAL=2;WKST=SU

==> (1997 9:00 AM EDT)September 2,16,30;October 14
(1997 9:00 AM EST)October 28;November 11,25;
December 9,23(1998 9:00 AM EST)January 6,20;February
...

Weekly on Tuesday and Thursday for 5 weeks:

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=WEEKLY;UNTIL=19971007T000000Z;
WKST=SU;BYDAY=TU,TH

RRULE:FREQ=WEEKLY;COUNT=10;WKST=SU;BYDAY=TU,TH

==> (1997 9:00 AM EDT)September 2,4,9,11,16,18,23,25,30;
October 2

Every other week on Monday, Wednesday and Friday until
December 24, 1997, but starting on Tuesday,
September 2, 1997:

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=WEEKLY;INTERVAL=2;UNTIL=19971224T000000Z;
WKST=SU;BYDAY=MO,WE,FR
==> (1997 9:00 AM EDT)September 2,3,5,15,17,19,29;October
1,3,13,15,17
(1997 9:00 AM EST)October 27,29,31;
November 10,12,14,24,26,28;
December 8,10,12,22

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Every other week on Tuesday and Thursday, for 8 occurrences:

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=8;WKST=SU;
BYDAY=TU,TH

==> (1997 9:00 AM EDT)September 2,4,16,18,30;
October 2,14,16

Monthly on
digits designating degrees. Longitudes west of the 1st Friday for ten occurrences:

DTSTART;TZID=US-Eastern:19970905T090000
RRULE:FREQ=MONTHLY;COUNT=10;BYDAY=1FR

==> (1997 9:00 AM EDT)September 5;October 3
(1997 9:00 AM EST)November 7;Dec 5
(1998 9:00 AM EST)January 2;February 6;
March 6;April 3
(1998 9:00 AM EDT)May 1;June 5

Monthly meridian shall
be designated by minus sign (-) preceding the digits designating
degrees. A point on the 1st Friday until December 24, 1997:

DTSTART;TZID=US-Eastern:19970905T090000
RRULE:FREQ=MONTHLY;UNTIL=19971224T000000Z;
BYDAY=1FR

==> (1997 9:00 AM EDT)September 5;October 3
(1997 9:00 AM EST)November 7;December 5

Every other month prime meridian shall be assigned to the
Eastern Hemisphere. A point on the 1st and 180th meridian shall be
assigned to the Western Hemisphere. One exception to this last Sunday
convention is permitted. For the special condition of describing
a band of latitude around the month earth, the East Bounding Coordinate
data element shall be assigned the value +180 (180) degrees.

Any spatial address with a latitude of +90 (90) or -90 degrees
will specify the position at the North or South Pole,
respectively. The component for 10
occurrences:

DTSTART;TZID=US-Eastern:19970907T090000
RRULE:FREQ=MONTHLY;INTERVAL=2;COUNT=10;
BYDAY=1SU,-1SU

==> (1997 9:00 AM EDT)September 7,28
(1997 9:00 AM EST)November 2,30

(1998 9:00 AM EST)January 4,25;March 1,29
(1998 9:00 AM EDT)May 3,31 longitude may have any legal
value.

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Monthly on June 2006

With the second to last Monday exception of the month for 6 months:

DTSTART;TZID=US-Eastern:19970922T090000
RRULE:FREQ=MONTHLY;COUNT=6;BYDAY=-2MO

==> (1997 9:00 AM EDT)September 22;October 20
(1997 9:00 AM EST)November 17;December 22
(1998 9:00 AM EST)January 19;February 16

Monthly on the third to the last day special condition described above, this
form is specified in Department of Commerce, 1986, Representation
of geographic point locations for information interchange (Federal
Information Processing Standard 70-1): Washington, Department of
Commerce, National Institute of Standards and Technology.

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 month, forever:

DTSTART;TZID=US-Eastern:19970928T090000
RRULE:FREQ=MONTHLY;BYMONTHDAY=-3

==> (1997 9:00 AM EDT)September 28
(1997 9:00 AM EST)October 29;November 28;
December 29(1998 9:00 AM EST)January 29;
February 26
...

Monthly on the 2nd following notation:

geo = "GEO" geoparam ":" geovalue CRLF

geoparam = *(";" xparam)

geovalue = float ";" float
;Latitude and 15th Longitude components

Example: The following is an example of this property:

GEO:37.386013;-122.082932

3.8.1.7. Location

Property Name: LOCATION

Purpose: The property defines the month intended venue for 10 occurrences:

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=MONTHLY;COUNT=10;BYMONTHDAY=2,15

==> (1997 9:00 AM EDT)September 2,15;October 2,15
(1997 9:00 AM EST)November 2,15;December 2,15
(1998 9:00 AM EST)January 2,15

Monthly on the first activity
defined by a calendar component.

Value Type: TEXT

Property Parameters: Non-standard, alternate text representation and last day
language property parameters can be specified on this property.

Conformance: This property can be specified in "VEVENT" or "VTODO"
calendar component.

Description: Specific venues such as conference or meeting rooms may
be explicitly specified using this property. An alternate
representation may be specified that is a URI that points to
directory information with more structured specification of the month
location. For example, the alternate representation may specify
either an LDAP URI pointing to an LDAP server entry or a CID URI
pointing to a MIME body part containing a vCard [RFC2426] for 10 occurrences:

DTSTART;TZID=US-Eastern:19970930T090000
RRULE:FREQ=MONTHLY;COUNT=10;BYMONTHDAY=1,-1

==> (1997 9:00 AM EDT)September 30;October 1
(1997 9:00 AM EST)October 31;November 1,30;
December 1,31(1998 9:00 AM EST)January 1,31;
February 1 the
location.

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Every 18 months on the 10th thru 15th of the month for 10
occurrences:

DTSTART;TZID=US-Eastern:19970910T090000
RRULE:FREQ=MONTHLY;INTERVAL=18;COUNT=10;
BYMONTHDAY=10,11,12,13,14,
15

==> (1997 9:00 AM EDT)September 10,11,12,13,14,15

(1999 9:00 AM EST)March 10,11,12,13

Every Tuesday, every other month:

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=MONTHLY;INTERVAL=2;BYDAY=TU

==> (1997 9:00 AM EDT)September 2,9,16,23,30
(1997 9:00 AM EST)November 4,11,18,25
(1998 9:00 AM EST)January 6,13,20,27;
March 3,10,17,24,31
...

Yearly in June and July for 10 occurrences:

DTSTART;TZID=US-Eastern:19970610T090000

RRULE:FREQ=YEARLY;COUNT=10;BYMONTH=6,7
==> (1997 9:00 AM EDT)June 10;July 10
(1998 9:00 AM EDT)June 10;July 10
(1999 9:00 AM EDT)June 10;July 10
(2000 9:00 AM EDT)June 10;July 10
(2001 9:00 AM EDT)June 10;July 10
Note: Since none of 2006

Format Definition: The property is defined by the BYDAY, BYMONTHDAY or
BYYEARDAY components following notation:

location = "LOCATION locparam ":" text CRLF

locparam = *(

; the following are specified, optional,
; but MUST NOT occur more than once

(";" altrepparam) / (";" languageparam) /

; the day following is
gotten from DTSTART

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Every other year on January, February, optional,
; and March
for 10 occurrences:

DTSTART;TZID=US-Eastern:19970310T090000
RRULE:FREQ=YEARLY;INTERVAL=2;COUNT=10;
BYMONTH=1,2,3

==> (1997 9:00 AM EST)March 10
(1999 9:00 AM EST)January 10;February 10;March 10
(2001 9:00 AM EST)January 10;February 10;March 10
(2003 9:00 AM EST)January 10;February 10;March 10

Every 3rd year on MAY occur more than once

(";" 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

3.8.1.8. Percent Complete

Property Name: PERCENT-COMPLETE

Purpose: This property is used by an assignee or delegatee of a to-do
to convey the 1st, 100th and 200th day
for 10 occurrences:

DTSTART;TZID=US-Eastern:19970101T090000
RRULE:FREQ=YEARLY;INTERVAL=3;COUNT=10;
BYYEARDAY=1,100,200

==> (1997 9:00 AM EST)January 1
(1997 9:00 AM EDT)April 10;July 19
(2000 9:00 AM EST)January 1
(2000 9:00 AM EDT)April 9;July 18
(2003 9:00 AM EST)January 1
(2003 9:00 AM EDT)April 10;July 19
(2006 9:00 AM EST)January 1

Every 20th Monday percent completion of a to-do to the year, forever:

DTSTART;TZID=US-Eastern:19970519T090000
RRULE:FREQ=YEARLY;BYDAY=20MO

==> (1997 9:00 AM EDT)May 19
(1998 9:00 AM EDT)May 18
(1999 9:00 AM EDT)May 17
...

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Monday Organizer.

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 one hundred. A value of week number 20 (where "0" indicates the default start to-do has not yet
been started. A value of "100" indicates that the week is Monday), forever:

DTSTART;TZID=US-Eastern:19970512T090000
RRULE:FREQ=YEARLY;BYWEEKNO=20;BYDAY=MO

==> (1997 9:00 AM EDT)May 12
(1998 9:00 AM EDT)May 11
(1999 9:00 AM EDT)May 17
...

Every Thursday to-do has been
completed. Integer values in March, forever:

DTSTART;TZID=US-Eastern:19970313T090000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=TH

==> (1997 9:00 AM EST)March 13,20,27
(1998 9:00 AM EST)March 5,12,19,26
(1999 9:00 AM EST)March 4,11,18,25
...

Every Thursday, but only during June, July, and August,
forever:

DTSTART;TZID=US-Eastern:19970605T090000
RRULE:FREQ=YEARLY;BYDAY=TH;BYMONTH=6,7,8

==> (1997 9:00 AM EDT)June 5,12,19,26;July 3,10,17,24,31;
August 7,14,21,28
(1998 9:00 AM EDT)June 4,11,18,25;July 2,9,16,23,30;
August 6,13,20,27
(1999 9:00 AM EDT)June 3,10,17,24;July 1,8,15,22,29;
August 5,12,19,26
...

Every Friday between indicate the 13th, forever:

DTSTART;TZID=US-Eastern:19970902T090000
EXDATE;TZID=US-Eastern:19970902T090000
RRULE:FREQ=MONTHLY;BYDAY=FR;BYMONTHDAY=13

==> (1998 9:00 AM EST)February 13;March 13;
November 13(1999 9:00 AM EDT)August 13
(2000 9:00 AM EDT)October 13
... percent
partially complete.

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The first Saturday that follows June 2006

When a to-do is assigned to multiple individuals, the first Sunday property
value indicates the percent complete for that portion of the month,
forever:

DTSTART;TZID=US-Eastern:19970913T090000
RRULE:FREQ=MONTHLY;BYDAY=SA;
BYMONTHDAY=7,8,9,10,11,12,13

==> (1997 9:00 AM EDT)September 13;October 11
(1997 9:00 AM EST)November 8;December 13
(1998 9:00 AM EST)January 10;February 7;March 7
(1998 9:00 AM EDT)April 11;May 9;June 13...
...

Every four years, to-do
assigned to the first Tuesday after assignee or delegatee. For example, if a Monday in November,
forever (U.S. Presidential Election day):

DTSTART;TZID=US-Eastern:19961105T090000
RRULE:FREQ=YEARLY;INTERVAL=4;BYMONTH=11;
BYDAY=TU;BYMONTHDAY=2,3,4,
5,6,7,8

==> (1996 9:00 AM EST)November 5
(2000 9:00 AM EST)November 7
(2004 9:00 AM EST)November 2
...

The 3rd instance into the month to-do is
assigned to both individuals "A" and "B". A reply from "A" with a
percent complete of one "70" indicates that "A" has completed 70% of Tuesday, Wednesday or
Thursday, for
the next 3 months:

DTSTART;TZID=US-Eastern:19970904T090000
RRULE:FREQ=MONTHLY;COUNT=3;BYDAY=TU,WE,TH;
BYSETPOS=3

==> (1997 9:00 AM EDT)September 4;October 7
(1997 9:00 AM EST)November 6

The 2nd to-do assigned to last weekday them. A reply from "B" with a percent
complete of "50" indicates "B" has completed 50% of the month:

DTSTART;TZID=US-Eastern:19970929T090000
RRULE:FREQ=MONTHLY;BYDAY=MO,TU,WE,TH,FR;
BYSETPOS=-2

==> (1997 9:00 AM EDT)September 29
(1997 9:00 AM EST)October 30;November 27;December 30
(1998 9:00 AM EST)January 29;February 26;March 30

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...

Every 3 hours from 9:00 AM to 5:00 PM on a specific day:

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=HOURLY;INTERVAL=3;UNTIL=19970902T170000Z

==> (September 2, 1997 EDT)09:00,12:00,15:00

Every 15 minutes for 6 occurrences:

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=MINUTELY;INTERVAL=15;COUNT=6

==> (September 2, 1997 EDT)09:00,09:15,09:30,09:45,10:00,10:15

Every hour and a half for 4 occurrences:

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=MINUTELY;INTERVAL=90;COUNT=4

==> (September 2, 1997 EDT)09:00,10:30;12:00;13:30

Every 20 minutes from 9:00 AM to 4:40 PM every day:

DTSTART;TZID=US-Eastern:19970902T090000
RRULE:FREQ=DAILY;BYHOUR=9,10,11,12,13,14,15,16;BYMINUTE=0,20,40
or
RRULE:FREQ=MINUTELY;INTERVAL=20;BYHOUR=9,10,11,12,13,14,15,16

==> (September 2, 1997 EDT)9:00,9:20,9:40,10:00,10:20,
... 16:00,16:20,16:40
(September 3, 1997 EDT)9:00,9:20,9:40,10:00,10:20,
...16:00,16:20,16:40
...

An example where the days generated makes a difference because of
WKST:

DTSTART;TZID=US-Eastern:19970805T090000
RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=MO

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==> (1997 EDT)Aug 5,10,19,24

changing only WKST from MO to SU, yields different results...

DTSTART;TZID=US-Eastern:19970805T090000
RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=SU
==> (1997 EDT)August 5,17,19,31

8.4. Alarm Component Properties

The following properties specify alarm information in calendar
components.

8.4.1. Action

Property Name: ACTION

Purpose: This property defines the action to-do
assigned to be invoked when an alarm
is triggered.

Value Type: TEXT

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This property MUST be specified once in a "VALARM"
calendar component.

Description: Each "VALARM" calendar component has a particular type
of action associated with it. This property specifies the type of
action them.

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

action

percent = "ACTION" actionparam "PERCENT-COMPLETE" pctparam ":" actionvalue integer CRLF

actionparam

pctparam = *(";" xparam)

actionvalue = "AUDIO" / "DISPLAY" / "EMAIL" / "PROCEDURE"
/ iana-token / x-name

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Example: The following are examples is an example of this property in a "VALARM"
calendar component:

ACTION:AUDIO

ACTION:DISPLAY

ACTION:PROCEDURE

8.4.2. Alarm Repeat Count to show 39%
completion:

PERCENT-COMPLETE:39

3.8.1.9. Priority

Property Name: REPEAT PRIORITY

Purpose: This The property defines the number of time the alarm should be
repeated, after the initial trigger. relative priority for a calendar
component.

Value Type: INTEGER

Property Parameters: Non-standard property parameters can be
specified on this property.

Conformance: This The property can be specified in a "VALARM" "VEVENT" or "VTODO"
calendar component.

Description: If the alarm triggers more than once, then this property
MUST be The priority is specified along with as an integer in the "DURATION" property.

Format Definition: The property range
zero to nine. A value of zero (US-ASCII decimal 48) specifies an
undefined priority. A value of one (US-ASCII decimal 49) is defined by the following notation:

repeatcnt = "REPEAT" repparam ":" integer CRLF
;Default
highest priority. A value of two (US-ASCII decimal 50) is "0", zero.

repparam = *(";" xparam)

Example: The following the
second highest priority. Subsequent numbers specify a decreasing
ordinal priority. A value of nine (US-ASCII decimal 58) is an example the
lowest priority.

A CUA with a three-level priority scheme of "HIGH", "MEDIUM" and
"LOW" is mapped into this property for an alarm such that repeats 4 additional times with a 5 minute delay after property value in
the
initial triggering range of the alarm:

REPEAT:4
DURATION:PT5M

8.4.3. Alarm Trigger

Property Name: TRIGGER

Purpose: This property one (US-ASCII decimal 49) to four (US-ASCII decimal
52) specifies when an alarm will trigger.

Value Type: The default "HIGH" priority. A value type of five (US-ASCII decimal
53) is DURATION. The the normal or "MEDIUM" priority. A value type can in the range of

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six (US- ASCII decimal 54) to a DATE-TIME nine (US-ASCII decimal 58) is "LOW"
priority.

A CUA with a priority schema of "A1", "A2", "A3", "B1", "B2", ...,
"C3" is mapped into this property such that a property value type, in which case the of
one (US-ASCII decimal 49) specifies "A1", a property value MUST
specify of two
(US- ASCII decimal 50) specifies "A2", a UTC formatted DATE-TIME value.

Property Parameters: Non-standard, property value data type, time zone
identifier or trigger relationship of three
(US-ASCII decimal 51) specifies "A3", and so forth up to a
property parameters can be
specified on value of 9 (US-ASCII decimal 58) specifies "C3".

Other integer values are reserved for future use.

Within a "VEVENT" calendar component, this property. The trigger relationship property
parameter MUST only be specified when specifies a
priority for the value type is DURATION.

Conformance: event. This property MUST may be specified in the "VALARM" calendar
component.

Description: useful when more
than one event is scheduled for a given time period.

Within the "VALARM" a "VTODO" calendar component, this property
defines when specified a
priority for the alarm will trigger. The default value type to-do. This property is
DURATION, specifying useful in prioritizing
multiple action items for a relative given time for the trigger of the alarm. period.

Format Definition: The default duration property is relative to the start of an event or to-do
that defined by the alarm following notation:

priority = "PRIORITY" prioparam ":" privalue CRLF
;Default is associated with. The duration can zero

prioparam = *(";" xparam)

privalue = integer ;Must be explicitly
set to trigger from either the end or in the start range [0..9]
; All other values are reserved for future use

The following is an example of the associated
event or to-do a property with the "RELATED" parameter. A value of START will
set the alarm to trigger off the start of the associated event or
to-do. A value of END will set the alarm to trigger off the end highest
priority:

PRIORITY:1

The following is an example of
the associated event or to-do.

Either a positive or negative duration may be specified for the
"TRIGGER" property. An alarm property with a positive duration next highest
priority:

PRIORITY:2

Example: The following is triggered
after the associated start or end an example of the event or to-do. An alarm
with a negative duration is triggered before the associated start or
end of the event or to-do.

The "RELATED" property parameter with no priority.

This is equivalent to not valid if the value type of specifying the "PRIORITY" property:

PRIORITY:0

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3.8.1.10. Resources

Property Name: RESOURCES

Purpose: This property is set to DATE-TIME (i.e., defines the equipment or resources anticipated
for an absolute date and time
alarm trigger). If activity specified by a value type of DATE-TIME is specified, then the calendar entity..

Value Type: TEXT

Property Parameters: Non-standard, alternate text representation and
language property value MUST parameters can be specified in the UTC time format. If an
absolute trigger is specified on an alarm for a recurring event or
to-do, then the alarm will only trigger for the specified absolute
date/time, along with any specified repeating instances.

If the trigger is set relative to START, then the "DTSTART" this property.

Conformance: This property
MUST can be present specified in the associated "VEVENT" or "VTODO"
calendar component. If an alarm is specified for an event with the trigger
set relative to the END, then the "DTEND"

Description: The property or the "DSTART"
and "DURATION' properties MUST be present in the associated "VEVENT"
calendar component. If the alarm value is specified for a to-do with a
trigger set relative to the END, then either the "DUE" property or
the "DSTART" and "DURATION' properties MUST be present in the
associated "VTODO" calendar component.

Alarms specified in an event or to-do which is defined in terms of a
DATE value type will arbitrary text. More than one
resource can be triggered relative to 00:00:00 UTC on the

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trigger will be relative to19980205T000000Z.
COMMA character (US-ASCII decimal 44).

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

trigger

resources = "TRIGGER" (trigrel / trigabs)

trigrel "RESOURCES" resrcparam ":" text *("," text) CRLF

resrcparam = *(

; the following are optional,
; but MUST NOT occur more than once

(";" "VALUE" "=" "DU