2.4.2.15 Call Completion

When making an outbound call, the unavailability of certain resources may prevent the call from reaching the connected state; e.g., if the destination party is busy or doesn't answer. Unavailable resources include trunk circuits as well as the destination party's station. TSPI_lineCompleteCall allows the TAPI DLL to specify how its wants to complete a call that cannot be completed normally. The TAPI DLL has the following options:

Camp on to queue the call until the call can be completed.
Call back requests the called station to return the call when it returns to idle. Answering the call back may automatically re-initiate (i.e., redial) the connection request.
Intrude allows the TAPI DLL to barge in to the existing call.
Message (aka "leave word calling") allows the TAPI DLL to send one of a small number of predefined messages to the destination. These messages can be text shown on the phone's display, a voice message left for the user, etc.

A call completion request can be canceled via TSPI_lineUncompleteCall. Multiple call completion request can potentially be outstanding for a given address at any one time. To identify individual requests, the implementation returns a completion ID. When a call completion request completes and results in a new call, then the call completion ID is available in the LINECALLINFO data structure returned by TSPI_lineGetCallInfo. Canceling a call completion request in progress also uses this call completion ID.

TSPI_lineCompleteCall

Places a call completion request.

TSPI_lineUncompleteCall

Cancels a call completion request.