2.4.1.10 Inbound Call Notification

After the TAPI DLL has opened a line device registering a media mode it can be notified when a call arrives. The Service Provider informs the TAPI DLL of a new incoming call via the LINE_NEWCALL callback message. This message passes the Service Provider's handle for the call to the TAPI DLL. The TAPI DLL returns its handle for the call. The Service Provider follows this with a LINE_CALLSTATE callback message. For an unanswered inbound call, the call state will be offering. The TAPI DLL can then invoke TSPI_lineGetCallInfo to find out information about the call. The fact that a call is offered may not necessarily imply the user is being alerted. A separate LINE_LINEDEVSTATE callback is made with a ringing indication to provide this information to the TAPI DLL.

Call information includes (among other things):

TSPI_lineSecureCall

Secures an existing call from interference by other events.