A Call Without an Owner - Telephony API Programmer's Reference

A Call Without an Owner

What happens to an incoming call if no applications have the line open with owner privilege? First, TAPI informs all monitoring applications on the line about the call. If no monitoring application switches to owner privilege to answer the call, the service provider eventually drops the call.

The following steps describe what normally happens if a line has only monitoring applications, a call comes in, and no applications answer the call. Assume that the service provider is not configured to answer new calls by itself.

The service provider passes the call handle to TAPI.
TAPI passes monitor handles to the monitor applications.
TAPI determines that the call is in the offering (not connected) state and lets the call "sit."
The remote party eventually hangs up, and the call reverts to the idle call state because it was never connected.
The monitors are notified that the call is idle and deallocate their handles if they have not already done so.
The last deallocation causes a TSPI_lineCloseCall.

Although the call in this example was never answered, its appearance and disappearance may have been significant to the applications monitoring the line. On a network that offers caller ID, a user may want to screen incoming calls, recording who has called without necessarily answering every call. Monitoring applications can help accomplish this without ever needing to answer a call.

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