Telephony is a technology that integrates computers with the telephone network. With telephony, people can use their computers to take advantage of a wide range of sophisticated communications features and services over a telephone line. The Win32 Telephony Service Provider Interface (TSPI) lets programmers develop telephony services that handle requests from applications to carry out and control communications over the telephone network.
Win32 Telephony supports both speech and data transmission, allows for a variety of terminal devices, and supports complex connection types and call-management techniques such as conference calls, call waiting, and voice mail. Telephony allows all elements of telephone usage to be controlled by applications through the Telephony Application Programming Interface (TAPI). These applications rely on the existence of service providers that support this functionality. The role of the service provider is to provide TSPI functions that carry out the tasks requested by applications using the TAPI functions.