Telephony Application Programming Interfaces

The Microsoft telephony application programming interfaces support the development of communications applications for Microsoft Windows. The telephony interfaces are listed in the following table.

Interface	Description
TAPI 2.x	A C-programming language based API that enables you to implement communications applications ranging from basic modem control to call centers with multiple agents and switches.
TAPI 3.x	A COM-based API that merges classic and IP telephony.
TSPI	A telephony service provider (TSP) is a dynamic-link library (DLL) that supports communications device control through a set of exported service functions. A TAPI application uses standardized commands, TAPI passes information to the telephony service provider, and the TSP handles the specific commands that must be exchanged with the device.
MSPI	A media service provider (MSP) allows an application considerable control over the media for a particular transport mechanism. An MSP is always paired with a telephony service provider (TSP).