The W3C Voice Browser Working Group has issued a last call Working Draft for Voice Browser Call Control: CCXML Version 1.0, incorporating some major changes in the Sections for Session Variables Documentation, Session Life-Cycle Details, Element and attribute name re-factoring, Meta and Metadata Features, Expanded Conferencing Events/Options, <dialogprepare>, Event I/O Updates, and VoiceXML Appendix.

The Call Control Extensible Markup Language (CCXML) is designed "to provide telephony call control support for VoiceXML or other dialog systems. CCXML has been designed to complement and integrate with a VoiceXML interpreter. Because of this there are many references to VoiceXML's capabilities and limitations. There are also details on how VoiceXML and CCXML can be integrated. However it should be noted that the two languages are separate and are not required in an implementation of either language. For example CCXML could be integrated with a more traditional Interactive Voice Response (IVR) system and VoiceXML or other dialog systems could be integrated with some other call control systems."

According to the WD Introduction, CCXML "can provide a complete telephony service application, comprised of Web server CGI compliant application logic, one or more CCXML documents to declare and perform call control actions, and to control one or more dialog applications that perform user media interactions. Since platforms implementing CCXML may choose to use one of many telephony call control definitions (e.g., JAIN Call Control, ECMA CSTA, S.100), the call control model in CCXML has been designed to be sufficiently abstract so that it can accommodate all major definitions. For relatively simple types of call control, this abstraction is straightforward. The philosophy in this regard has been to 'make simple things simple to do.' Outdial, transfer (redirect), two-party bridging, and many forms of multi-party conferences fall within this classification."

Bibliographic Information

Voice Browser Call Control: CCXML Version 1.0. Edited by RJ Auburn (Voxeo). W3C Working Draft 30-April-2004. Version URL: http://www.w3.org/TR/2004/WD-ccxml-20040430/. Latest version URL: http://www.w3.org/TR/ccxml/. Previous version URL: http://www.w3.org/TR/2003/WD-ccxml-20030612/.

Appendices: Appendix A - Related Work; Appendix B - CCXML DTD; Appendix C - CCXML Schema; Appendix D - VoiceXML 2.0 Integration Details; Appendix E - Recommended Telephony Protocol Names; Appendix F - Changes; Appendix G - Acknowledgments; Appendix H - References; Appendix I - CCXML Media Type.

Status: "Although an Implementation Report Plan has not yet been developed for this specification, the Working Group currently expects to require at least two independently developed interoperable implementations of each required feature, and at least one implementation of each feature, in order to exit the next phase of this document, the Candidate Recommendation phase. To help the Voice Browser Working Group build such a report, reviewers are encouraged to implement this specification and to indicate to W3C which features have been implemented, and any problems that arose..."

Motivation for Voice Browser Call Control

"CCXML is designed to complement VoiceXML by providing advanced telephony functions. It also can be used as a third-party call control manager in any telephony system. This document contains references to VoiceXML's capabilities and limitations, as well as details on how VoiceXML and CCXML can be integrated.

The CCXML specification originated from the desire to handle call control requirements that were beyond the scope of the VoiceXML specification. The following requirements are addressed by this specification:

• Support for multi-party conferencing, with advanced conference and audio control. A conferencing application is a multi-dialog manager and is dependent upon call control.
• The ability to give each active call leg its own dedicated VoiceXML interpreter. For example, in VoiceXML, the second leg of a transferred call lacks a VoiceXML interpreter of its own, limiting the scope of possible applications.
• Sophisticated multiple-call handling and control, including the ability to place outgoing calls.
• Handling for a richer class of asynchronous events. Advanced telephony operations involve substantial amounts of signals, status events, and message-passing. VoiceXML does not integrate asynchronous "external" events into its event-processing model.
• The ability to receive events and messages from external computational entities. Interacting with an outside call queue, or placing calls on behalf of a document server, means that VoiceXML must have additional external interfaces.

CCXML and VoiceXML implementations are not mutually dependent. A CCXML implementation may or may not support voice dialogs, or may support dialog languages other than VoiceXML..." [from the spec Introduction]

Related News: W3C Synchronized Multimedia Activity Relaunched

"W3C is pleased to announce the relaunch of the Synchronized Multimedia (SYMM) Activity. The Synchronized Multimedia Working Group is co-chaired by Yoshihisa Gonno (Sony) and Guido Grassel (Nokia) and will extend the SMIL 2.0 W3C Recommendation. The Timed Text Working Group is chaired by Glenn Adams (XFSI) and is developing XML vocabulary and document types for subtitles and captions. Participation is open to W3C Members. Visit the Synchronized Multimedia home page."