Telephony Server Application Programming Interface was a

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 coordinated. The term is predominantly used to describe desktop ...

standard developed and promoted by Novell and

AT&T AT&T Inc. is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's largest telecommunications company by revenue and the third largest provider of mobile te ...

. It consisted of a number of call control commands for switching calls,

voice mail A voicemail system (also known as voice message or voice bank) is a computer-based system that allows users and subscribers to exchange personal voice messages; to select and deliver voice information; and to process transactions relating to ind ...

and call logging using NetWare servers. Unlike the competing

Telephony Application Programming Interface The Telephony Application Programming Interface (TAPI) 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 diff ...

from

Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washin ...

and

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...

, it was a

server Server may refer to: Computing *Server (computing), a computer program or a device that provides functionality for other programs or devices, called clients Role * Waiting staff, those who work at a restaurant or a bar attending customers and su ...

-based system that did not expect client-side equipment to handle call switching. This was important to AT&T, which sold large telephone switches that Telephony Server Application Programming Interface was intended to work with.

Description

Telephony Server Application Programming Interface consisted of two primary parts, the application programming interface itself, and a "telephony service provider" that ran on a server and talked to 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 An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also i ...

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 private branch exchange driver was known as "NetWare Telephony Services", at least when using Novell software. Message formats were based on a standard promoted by the

European Computer Manufacturers Association Ecma International () is a nonprofit standards organization for information and communication systems. It acquired its current name in 1994, when the European Computer Manufacturers Association (ECMA) changed its name to reflect the organization ...

, which was directly supported by a number of European-built switches. When used with one of these switches, the driver between the server and the switch was "thin". "Thicker" drivers were needed for switches that did not directly support these standards. The client-side application programming interface was available for

Windows 3.1 Windows 3.1 is a major release of Microsoft Windows. It was released to manufacturing on April 6, 1992, as a successor to Windows 3.0. Like its predecessors, the Windows 3.1 series ran as a shell on top of MS-DOS. Codenamed Janus, Windows 3 ...

Windows 95 Windows 95 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of operating systems. The first operating system in the 9x family, it is the successor to Windows 3.1x, and was released to manufacturi ...

Windows NT Windows NT is a proprietary graphical operating system produced by Microsoft, the first version of which was released on July 27, 1993. It is a processor-independent, multiprocessing and multi-user operating system. The first version of Win ...

OS/2 OS/2 (Operating System/2) is a series of computer operating systems, initially created by Microsoft and IBM under the leadership of IBM software designer Ed Iacobucci. As a result of a feud between the two companies over how to position OS/2 r ...

Mac OS Two major famlies of Mac operating systems were developed by Apple Inc. In 1984, Apple debuted the operating system that is now known as the "Classic" Mac OS with its release of the original Macintosh System Software. The system, rebranded "M ...

, UnixWare and

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, w ...

.https://downloads.avaya.com/css/P8/documents/101014061 Installation Guide The interface was a control protocol only, and did not send a voice data across the network for use with software-based phones. It included commands for dialing, hanging up, and other instructions. It required a channel, called a ''stream'', to be set up for all communications.

Telephony Server Application Programming Interface and Versit

Telephony Server Application Programming Interface was 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. Only the control system was standardized; 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 GeoPort is a serial data system used on some models of the Apple Macintosh that could be externally clocked to run at a 2 Mbit/s data rate. GeoPort slightly modified the existing Mac serial port pins to allow the computer's internal DSP hardware o ...

as the computer-end of such a system, and selected Telephony Server Application Programming Interface as the messaging protocol. The various vendors formed the

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 (PDI) technology, open specifications for exchanging personal data over the Inter ...

and published "The Versit CTI Encyclopedia." The Encyclopedia expanded the basic 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.

References

{{Reflist * Paul Cronin
"An Introduction to TSAPI and Network Telephony"
''IEEE Communications'', April 1996
"Telephony Services Application Programming Interface (TSAPI)"
NetWare Software Developer Kit, Release 5 (or later) xx Link is dead xx Application programming interfaces Telephone service enhanced features