Customizing RTC (Windows CE 5.0)
This topic outlines the customization options provided by the RTC Client API. For detailed information about these options see Common IP Phone Customization Tasks and Real-time Communications (RTC) Client API.
You cannot customize the implementation to change how the RTC Client API operates. Instead, you can customize or use RTC independently of other VoIP features in one of the ways outlined in the following list.
To provide presence and instant messaging, in addition to a custom SIP stack. The SIP stack implemented in the RTC Client API Catalog item provides tested access to presence and instant messaging functionality supplied by Microsoft Live Communication Server (LCS).
Even if your phone uses another SIP stack for signaling, the phone application can, as the TUI does, use the RTC Client API Catalog item to retrieve and provide presence information by means of a LCS server computer.
This can be implemented in a variety of ways. One possibility is to customize the application so that it calls RTC Client API functions directly for presence, and at the same time customize the VAIL to use a custom SIP stack for signaling.
With an implementation like this, the phone sends and receives SIP messages using different SIP stacks. (If you use two stacks, be sure each stack listens for SIP datagrams on a different port. You can change the ports used by the RTC Client API SIP stack with the IRTCClient2::AllowedPorts method. Your custom SIP stack should also provide a mechanism for customizing the ports it uses.)
To provide media transport only. The VAIL uses an IVoIPMediaMgr implementation to transfer media. You can replace the VAIL's signaling SIP stack but keep the default implementation of IVoIPMediaMgr, which uses the RTC Client API Catalog item for media transport. In this scenario, the RTC Client API Catalog item is responsible only for transferring media and is not used for signaling. For information about replacing the SIP stack, see Using the TUI and the VAIL with a Custom SIP Stack.
Separately from the TUI and the VAIL, to provide real-time communication functionality. Because the RTC Client API is a library of functions (exposed as COM objects), you can use it independently of the TUI and the VAIL to provide all or any part of real-time communication functionality that your phone requires. This requires that you implement your own UI and the common functionality provided by VAIL.
See Also
Customizing IP Phone Functionality | Common IP Phone Customization Tasks | Adding or Changing SIP Headers and Verbs | Supporting Video Conferencing | Using Multiple SIP Stacks | Changing the Media Transport Implementation
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