Telephony Server Application Programming Interface
Encyclopedia
TSAPI, short for Telephony Server Application Programming Interface, was a computer telephony integration
standard developed and promoted by Novell
and AT&T
. It consisted of a number of call control commands for switching calls, voice mail and call logging using Netware servers. Unlike the competing TAPI
from Microsoft
/Intel, TSAPI was a server
-based system and did not expect clients to switch calls. This was important to AT&T, who sold large telephone switches that TSAPI was intended to work with.
itself, and a "telephony service provider" that ran on a server and talked to TSAPI clients. Novell produced one such provider, "TServer" that ran, unsurprisingly, on NetWare servers. TServer, in turn, talked to a driver specific to the brand of telephony switch being used. NetWare acted primarily as the operating system
for TServer to run within, although TServer did make use of NetWare Directory Services for security and provisioning. The whole system from client-side drivers to server to PXB driver was known as "NetWare Telephony Services" (NTS), at least when using Novell software from top to bottom.
The TSAPI message formats were based on a standard promoted by the European Computer Manufacturers Association, which was directly supported by a number of European-built switches. When used with one of these switches, the driver between the TSAPI server and the switch was "thin". "Thicker" drivers were needed for switches that did not directly support these standards. The client-side TSAPI API was available for Windows 3.1, Windows 95
, Windows NT
, OS/2
, Mac OS
and UnixWare
.
TSAPI is a control protocol only, it does not send actual voice data across the network for use with software-based phones. It includes commands for dialing, hanging up and so forth. TSAPI is a stateful protocol that required a channel, referred to as a stream, to be set up for all communications.
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.
Computer telephony integration
Computer telephony integration, also called computer–telephone integration or CTI, is a common name for any technology that allows interactions on a telephone and a computer to be integrated or coordinated...
standard developed and promoted by Novell
Novell
Novell, Inc. is a multinational software and services company. It is a wholly owned subsidiary of The Attachmate Group. It specializes in network operating systems, such as Novell NetWare; systems management solutions, such as Novell ZENworks; and collaboration solutions, such as Novell Groupwise...
and AT&T
AT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...
. It consisted of a number of call control commands for switching calls, voice mail and call logging using Netware servers. Unlike the competing TAPI
Telephony Application Programming Interface
The Telephony Application Programming Interface is a Microsoft Windows API, which provides computer telephony integration and enables PCs running Microsoft Windows to use telephone services. Different versions of TAPI are available on different versions of Windows...
from Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
/Intel, TSAPI was a server
Server (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...
-based system and did not expect clients to switch calls. This was important to AT&T, who sold large telephone switches that TSAPI was intended to work with.
Description
TSAPI consisted of two primary parts, the TSAPI application programming interfaceApplication programming interface
An application programming interface is a source code based specification intended to be used as an interface by software components to communicate with each other...
itself, and a "telephony service provider" that ran on a server and talked to TSAPI clients. Novell produced one such provider, "TServer" that ran, unsurprisingly, on NetWare servers. TServer, in turn, talked to a driver specific to the brand of telephony switch being used. NetWare acted primarily as the operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
for TServer to run within, although TServer did make use of NetWare Directory Services for security and provisioning. The whole system from client-side drivers to server to PXB driver was known as "NetWare Telephony Services" (NTS), at least when using Novell software from top to bottom.
The TSAPI message formats were based on a standard promoted by the European Computer Manufacturers Association, which was directly supported by a number of European-built switches. When used with one of these switches, the driver between the TSAPI server and the switch was "thin". "Thicker" drivers were needed for switches that did not directly support these standards. The client-side TSAPI API was available for Windows 3.1, Windows 95
Windows 95
Windows 95 is a consumer-oriented graphical user interface-based operating system. It was released on August 24, 1995 by Microsoft, and was a significant progression from the company's previous Windows products...
, Windows NT
Windows NT
Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was intended to complement...
, OS/2
OS/2
OS/2 is a computer operating system, initially created by Microsoft and IBM, then later developed by IBM exclusively. The name stands for "Operating System/2," because it was introduced as part of the same generation change release as IBM's "Personal System/2 " line of second-generation personal...
, Mac OS
Mac OS
Mac OS is a series of graphical user interface-based operating systems developed by Apple Inc. for their Macintosh line of computer systems. The Macintosh user experience is credited with popularizing the graphical user interface...
and UnixWare
UnixWare
UnixWare is a Unix operating system maintained by The SCO Group . UnixWare is typically deployed as a server rather than desktop. Binary distributions of UnixWare are available for x86 architecture computers. It was originally released by Univel, a jointly owned venture of AT&T's Unix System...
.
TSAPI is a control protocol only, it does not send actual voice data across the network for use with software-based phones. It includes commands for dialing, hanging up and so forth. TSAPI is a stateful protocol that required a channel, referred to as a stream, to be set up for all communications.
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
Apple Computer
Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...
was promoting GeoPort
GeoPort
GeoPort was a serial data system used on some models of the Apple Macintosh. GeoPort slightly modified the existing Mac serial port pins to allow the computer's internal sound hardware to emulate various devices such as modems and fax machines. GeoPort could be found on late-model m68k-based...
as the computer-end of such a system, and selected TSAPI as the messaging protocol. The various vendors formed the Versit Consortium
Versit Consortium
The Versit Consortium was a multivendor initiative founded by Apple Computer, AT&T, IBM and Siemens in the early 1990s in order to create Personal Data Interchange technology, open specifications for exchanging personal data over the Internet, wired and wireless connectivity and Computer Telephony...
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.