Telephony Server Application Programming Interface was a

computer telephony integration Computer-telephony integration, also called computer–telephone integration or CTI, is a general term for technologies that coordinate interactions between telephones and a computers to be coordinated. The term is predominantly used to descri ...

standard developed and promoted by

Novell Novell, Inc. () was an American software and services company headquartered in Provo, Utah, that existed from 1980 until 2014. Its most significant product was the multi-platform network operating system known as NetWare. Novell technolog ...

and

AT&T AT&T Inc., an abbreviation for its predecessor's former name, the American Telephone and Telegraph Company, is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the w ...

. 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 callers to leave a Voice recording, recorded message when the recipient has been unable (or unwilling) to answer the Telephone, phone. Calls may ...

and call logging using

NetWare NetWare is a discontinued computer network operating system developed by Novell, Inc. It initially used cooperative multitasking to run various services on a personal computer, using the IPX network protocol. The final update release was ver ...

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 diffe ...

from

Microsoft Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The ear ...

and

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, and Delaware General Corporation Law, incorporated in Delaware. Intel designs, manufactures, and sells computer compo ...

, it was a

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

-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 An application programming interface (API) is a connection between computers or between computer programs. It is a type of software Interface (computing), interface, offering a service to other pieces of software. A document or standard that des ...

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 and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

for TServer to run within, although TServer did make use of

NetWare Directory Services eDirectory is an X.500-compatible directory service software product from NetIQ. Previously owned by Novell, the product has also been known as Novell Directory Services (NDS) and sometimes referred to as ''NetWare Directory Services''. NDS was ...

for security and provisioning. The whole system from client-side drivers to server to

private branch exchange A business telephone system is a telephone system typically used in business environments, encompassing the range of technology from the key telephone system (KTS) to the private branch exchange (PBX). A business telephone system differs from ...

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 run as a shell on top of MS-DOS; it was the last Windows 1 ...

Windows 95 Windows 95 is a consumer-oriented operating system developed by Microsoft and the first of its Windows 9x family of operating systems, released to manufacturing on July 14, 1995, and generally to retail on August 24, 1995. Windows 95 merged ...

Windows NT Windows NT is a Proprietary software, proprietary Graphical user interface, graphical operating system produced by Microsoft as part of its Windows product line, the first version of which, Windows NT 3.1, was released on July 27, 1993. Original ...

OS/2 OS/2 is a Proprietary software, proprietary computer operating system for x86 and PowerPC based personal computers. It was created and initially developed jointly by IBM and Microsoft, under the leadership of IBM software designer Ed Iacobucci, ...

Mac OS Mac operating systems were developed by Apple Inc. in a succession of two major series. 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 ...

UnixWare UnixWare is a Unix operating system. It was originally released by Univel, a jointly owned venture of AT&T's Unix System Laboratories (USL) and Novell. It was then taken over by Novell. Via Santa Cruz Operation (SCO), it went on to Caldera Syst ...

and

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

.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 Apple Inc. is an American multinational corporation and technology company headquartered in Cupertino, California, in Silicon Valley. It is best known for its consumer electronics, software, and services. Founded in 1976 as Apple Computer Co ...

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 megabit per second data rate. GeoPort slightly modified the existing Mac serial port pins to allow the computer's internal ...

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 Intern ...

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