The implementation sends the PHONE_DEVSPECIFIC message to an application to notify the application about device-specific events occurring at the phone. The meaning of the message and the interpretation of the parameters is implementation-defined.
PHONE_DEVSPECIFIC
hPhone = (HPHONE) hPhoneDevice;
dwCallbackInstance = (DWORD) hCallback;
dwParam1 = (DWORD) DeviceSpecific1;
dwParam2 = (DWORD) DeviceSpecific2;
dwParam3 = (DWORD) DeviceSpecific3;
No return value.
Version: Use TAPI version 1.4 and later.
Header: Declared in tapi.h.