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Incoming Calls

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When an incoming call reaches the target application and the application is an owner of the call, the call goes through the following steps.

  1. First, the service provider learns of the new incoming call.
  2. The call is passed to TAPI.
  3. TAPI hands the call over to the appropriate application.
  4. The application accepts, answers, rejects, or redirects the call.
  5. Finally, applications conduct probing, if necessary, which can cause the call to be handed off between applications one or more times.

An application that is based on Windows CE and that uses a modem to accept incoming calls must be able to initialize the modem, open the line, wait for a telephone call, accept the call, and disconnect when the session is complete.

To accept an incoming call by using TAPI

  1. Call the lineInitialize function to initialize TAPI.
  2. Call the lineOpen function to open the line and specify the media modes that you want to detect.
  3. A LINE_APPNEWCALL message is sent to the highest-priority application with the line opened for the initial media mode of the call. Other applications will receive a LINE_CALLSTATE message with a call state of LINECALLSTATE_OFFERING.
  4. An application must have a call handle with a call privilege of LINECALLPRIVILEGE_OWNER in order to call the lineAnswer function successfully to initiate the completion of the call-connection process.

An application might have to use the lineSetCallPrivilege function to change the privilege of its call handle.

See Also

Establishing a Modem Connection | Identifying Incoming Calls | The LINECALLINFO Data Structure | Incoming Calls and Line Privileges | TAPI Functions

 Last updated on Saturday, April 10, 2004

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