Fix PC Error

None. Because TAPI.DLL catches the bad device ID before it was passed to the service provider, the code on ATSP was never executed. The code on the ATSP sample was an artifact of an earlier (beta) version of TAPI.DLL. In general, TApplication Programming Interface pre-validates many parameters, and the documentation explicitly indicates only those cases where a parameter was not pre- validated. Even so, there are certain places on the sample service provider in which the return codes still exist for pre-validated parameters. For example, line handles are supposed to be pre-validated, but functions in the sample service provider still have code that returns LINEERR_INVALLINEHANDLE.

the code was to handle rare race conditions where TAPI.DLL "thinks" that a line handle was still valid but the service provider doesn't think that the line handle was still valid. the race condition occurs only if the provider issues the LINE_CLOSE message, indicating the provider...