Transmitting a Fax to an Active Inbound Call

Transmitting a document using an existing inbound line connection saves the transmission cost of the fax. This is known as a "faxback service."

To successfully transmit a document using an existing inbound line connection, the call must be in the LINECALLSTATE_CONNECTED state. The underlying hardware must also support turning a call around. For more information, see LINE_CALLSTATE and LINECALLSTATE_ Constants, both in the TAPI documentation.

In the Win32 Environment

To transmit a fax using an existing line connection, specify the CallHandle member of the FAX_JOB_PARAM structure when you call the FaxSendDocument or FaxSendDocumentForBroadcast functions. The call handle must be one retrieved by the TAPI LINE_CALLSTATE message. If the CallHandle member is specified, the application should transmit the fax using the existing line connection instead of initiating a new call.

In the COM Implementation Environment

If you are writing a C/C++ application, you can set the CallHandle property or the ConnectionObject property to enable transmission of a fax using an existing line connection. To transmit a fax to an active inbound TAPI 2.x call, call the IFaxDoc::put_CallHandle interface method. To store a reference to a TAPI 3.0 call object in a FaxDoc object, call the IFaxDoc::putref_ConnectionObject method. The ConnectionObject property provides complete COM-based functionality when transmitting a fax using an existing line connection. For information about the steps required to create a FaxDoc object, and for a list of properties and methods, see IFaxDoc.

If you are writing a Visual Basic application, you can set the ConnectionObject property of a FaxDoc object. This property provides complete COM-based functionality when transmitting a fax using an existing line connection. See FaxDoc object (Visual Basic) for more information about the steps required to create the object, and for a list of properties and methods of the object.