Telephony Server Application Programming Interface - TSAPI and Versit

TSAPI and Versit

TSAPI was being created in an era when major telephony vendors were promoting a vision of wide-area networking based on dedicated circuit-switched links. Unlike modern networking systems where each piece of data is separately routed to its destination, these networking systems were essentially a version of the existing phone system carrying data instead of voice, setting up dedicated channels between endpoints. Looking for applications that might make use of such a network, vendors promoted numerous new standards for videotelephony, high-speed fax, etc.

TSAPI standardized only the control system; getting data into and out of a computer remained an issue. There were a number of efforts by various vendors to support this functionality. Apple Computer was promoting GeoPort as the computer-end of such a system, and selected TSAPI as the messaging protocol. The various vendors formed the Versit Consortium and published the "The Versit CTI Encyclopedia." The Encyclopedia expanded the basic TSAPI system to include a data-type identifier to allow it to switch any sort of "call". Additionally, Versit allowed that data to be switched to the computer using GeoPort or a number of other connection options.