hidphone.tsp

Telephony service provider Reference

A .tsp file is a telephony service provider for TAPI, the Telephony Application Programming Interface of Windows. The file is a DLL in the PE format. It connects the TAPI system to real telephony hardware or services, for example modems. Windows ships providers such as unimdm.tsp for modems. Applications reach the provider only through TAPI.

A file extension is only a part of the file name. It does not give a guarantee about the format or the content of a file. But on Windows, the extension selects the program that opens the file.