The abbreviation TAPI stands for Telephony Application Programming Interface and refers to a programming interface for telephony applications. TAPI was originally developed by Microsoft and Intel and introduced as early as 1993. From Windows 95 onwards, the interface has been an integral part of the functionality and embedded in the software of that operating system. Since its introduction it has been updated several times and several different versions now exist. As of version 3.0, from 1999, the interface has also supported IP telephony and access video and audio streams, in addition to traditional telephone services. Part of the interface is the TAPI32.DLL, which provides standard functions for developing telephony applications. In turn, TAPI32.DLL communicates via the TSPI interface with the TAPI Service Provider, which translates the desired functions into a language that the hardware can interpret and then passes that on to the telephony hardware.