Most of the Get and Set operations described in the topics in this section deal with only one component of information. The operation TSPI_phoneGetStatus allows TAPI to obtain complete status information about a phone device.
Whenever a status item changes on the phone device, the service provider sends a PHONE_STATE message to the TAPI callback function. The message parameters include a handle to the phone device and an indication of the status item that changed. TAPI can use TSPI_phoneSetStatusMessages to select status changes for which it wants to be notified in the callback message. In contrast, TAPI has no corresponding TSPI_phoneSetStatusMessages function. TAPI tracks which applications have enabled which status messages.