see Closed Circuit Television


see Central Control Unit


see Call Detail Record

Central Control Unit

The Central Control Unit (CCU) is the box or cabinet that houses the hardware controlling the telephone system.


Centrex (short for Central Exchange) is a hosted telephony solution providing the functionality of a PBX without the costs and logistics associated with a physical on-premise system.

Class of Service

The ability to give a data packet a series of set properties/restrictions/access levels during a telephone call. E.g. A user can be given a COS value of 1 that permits international dialling while the value of 2 disables this ability.


see Calling Line Identity


see Calling Line Identity Presentation


see Calling Line Identity Restriction

Closed Circuit Television

Closed Circuit Television (CCTV) is the security and surveillance devices that can aide with access control and the broader protection of premises.


Cloud can relate to any kind of infrastructure, platform or applications that are hosted on a server not located at the premises using it, accessed via the internet. E.g. cloud communications enable the functionality of a telephone system with no requirement for an on-site PBX.


A codec is a device or piece of computer software for coding or decoding digital data streams or signals.

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