Glossary. Definitions of some telecoms jargon.

Auto Attendant

An automated answering system that puts the caller through to the correct short dial/extension or department in the company by keys on a handset e.g. Press 1 for Sales.


Bandwidth is a measurement that gives an indication of the amount of data that can be transferred through a connection in certain amount of time. In either bps (bits per second) or bytes per second.

Call Divert

A feature that allows users to use another number to re-direct their calls to eg. another extension, group, voicemail or external number.

Call Forwarding

A feature that enables incoming calls to be forwarded to a different number, eg another extension, group, voicemail or external number.


This is another word for telephone line used in reference to digital lines.

Cloud Telephony

Cloud or Hosted telephony is a system that resides in the cloud rather than physically in the form of a PBX in your office.


This stands for Direct dial in. When calls are made to a particular numbers they will directly dial to an individual’s extension/one number. This enables them to be called directly or automatically through a switchboard without needed a receptionist.


Or in other words Do not disturb. You can set your phone to DND if you don’t want to be contacted for example if you are in a meeting.


Domain Name Service converts domain names to a IP address which a computer can ask to be routed by a network.


A collection of frame-based computer networking technologies for local area networks.


A piece of equipment that converts voice, video or fax in real-time to and from the PSTN to an IP network.


In terms of telephony this phrase is used to describe a service that is provided to the customer using equipment that is located remotely from their facility or in the ‘cloud’.

Hunt Groups

This allows a group of extensions or one numbers to be grouped together for example to be part of a department in a company for example support and calls will ring round them until it is answered.

IP – Internet Protocol

A term used to describe IP signalling methods and the way that voice traffic and data signals can be sent between devices connected to a network, internet and LANs.


Also known as an Integrated Services Digital Network. ISDN is a digital public network for voice and data communications.


A computer network within a limited area such as a building or office space.


Interactive Voice Recognition see auto attendant.

Internet Service Provider

An organization that provides access to the Internet.


A Private Branch Exchange is a private business telephone system.


Procedures in regard to the transmission of data between two devices.


Power over Ethernet allows electrical power to be transmitted through ethernet cables.


A Public Switched Telephone Network was traditionally analogue but now includes digital (ISDN).


Provides adequate voice quality across IP networks.


A network device that that handles message transfer between devices.


Session Initiation Protocol

SIP Trunking

A SIP trunk is a pure IP connection between your premises and the national telephone network.


A mobile phone that can browse the internet, receive email etc.


A trunk is a ‘line’ or ‘channel’ that you need for making a call.


A Virtual Private Network is a fast and secure way to transfer data between remote sites.


Voice over Internet Protocol is voice traffic passing over a WAN, VPN or the internet.


A large area computer network that isn’t just limited to one area.

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