Terminal Adapter

Allows existing non-ISDN terminals to operate on ISDN lines. It provides conversion between a non-ISDN terminal device and the ISDN user/network interface.


An exchange used to switch network traffic between other nodes.


Trunk Access Class


Telephony Applications Programmers Interface
 - A standard for CTI developed by Microsoft and Intel associated with PC based computer systems. It is an open standard which permits the direct control of a telephone from a windows based application.


Transport Control Protocol/Internet Protocol

Terminal Equipment Type 1

ISDN-compatible terminals. A TE1 can be an ISDN telephone, a personal computer capable of working with ISDN, a video-phone etc any device that can attach to and work with ISDN.


Network terminal emulation protocol. Simple protocol to allow programs to exchange ASCII and control characters over network interfaces, as though the data were being produced/displayed by a normal terminal.


Any device capable of sending or receiving information over a communication channel.

Tie Line

A permanent communications link between 2 or more PBXs provided by a PTT/PTO.


An individual circuit, provided by either a public network operator or via a private network capable of carrying an individual telephone call (either incoming or outgoing).


Telephony Service Application Prog Interface - 
The equivalent of TAPI in a Novell environment where control of the telephone is initiated over the LAN rather than by direct connection to the telephone.