A signalling system used for linking two pieces of telecommunications equipment (e.g. two telephone systems) over a distance.

Account Code

A way of attaching a "tag" to a call record. This might be used to indicate that the call is to be charged to a particular account or to indicate the outcome of a call (a sale was made, a brochure requested etc.) Call Management systems can then produce reports listing all calls with the same account codes. Account codes can be attached to incoming and outgoing calls, and it can be made mandatory for an extension user to enter an account code before a call is made.


Automatic Call Distribution
 - An automated system for answering, queuing and distributing incoming calls to a number of agents. Popular in call centres, ACD systems also provide statistics, such as the number of calls waiting, average length of call queue etc, which can be incorporated into historical reports or displayed in real time on electronic wallboards.


A device that (1) enables different sizes or types of plugs to mate with one another or to fit into an information outlet, (2) provides for the rearrangement of leads, (3) allows large cables with numerous wires to fan out into smaller groups of wires, or (4) makes interconnections between cables.

Ad Hoc Cabling

Cabling scheme where different types of cabling components from different vendors are linked together to form a cabling system.


Asynchronous Digital Subscriber Line
A broadband technology that delivers high data transfer speeds over existing phone lines. Can reach speeds up to 2 mb.


Super Asynchronous Digital Subscriber Line
Speeds greater than 2 mb.

Alpha Tagging

The assignment of an alpha-numeric name to a facility. For example when called by an extension your phone can display the name of the caller rather than the extension number. When an incoming DDI call is received a name can be shown which relates to the number that was dialled, enabling one person to answer calls in a variety of different ways, e.g. in the names of different companies.

Analogue Device

A device that can be attached to an ordinary analogue telephone line, such as a telephone, fax machine, cordless phone, answering machine, modem etc.


Automatic Route Selection. A technique where the telephone system looks at the digits being dialled to make an outside call and automatically routes the call via an alternate route. Best possible cost efficiencies for outgoing or inter site calls.


American Standard Code for Information Interchange
List of 128 characters, specified in set order. Each character is numbered according to its position in the list.

Asymmetrical Duplex

Asymmetrical Duplex Data flows in both directions at the same time however at different speeds.


Asynchronous Transfer Mode
 - A transmission and switching technique capable of supporting voice, video and data (Multimedia) communications It is unique in that each piece of information is addressed and is of the same length. This allows very high-speed communications.

Auto Attendant

An automated answering system that uses prompts to direct callers to the correct department or extension - e.g. "For Support press 1"