AT&T AT&T Bus, Time Division Multiplex, CCS Hundred Call Seconds, Call Appearance, Voice Terminal

dedicated trunks and a shared

Bus, Time Division Multiplex

See Time Division Multiplex Bus.

CCS (Hundred Call Seconds)

Atraffic-measuring unit that expresses the load of one or more traffic-handling devices. A device used for 1 hour without interruption generates 36 CCS which equals 1 erlang (see Erlang).

Call Appearance, Attendant Console

Two buttons, labeled System Access, used to originate, receive, and hold calls. Each button has two associated LEDs to show the status of the call appearance.

Call Appearance, Voice Terminal

A button labeled with an extension number used to place outgoing calls, receive incoming calls, or hold calls. Two LEDs next to the button show the status of the call appearance or status of the call.

Central Office

The location housing telephone switching equipment that provides local telephone service and access to toll facilities for long-distance calling.

Central Office Codes

The first three digits of a 7-digit public network telephone number. These codes are numbered from 200 through 999 and are sometimes referred to as NNXs.

Central Office Trunk

A telecommunications channel that provides access from the system to the public network through the local central office.

Channel

A communications path for transmitting voice and data.

Class of Service (COS)

Parameters used to define voice terminal, data, and trunk port capabilities and restrictions.

Common Control Switching Arrangement (CCSA)

A private telecommunications network using switching center for interconnecting company locations.

Confirmation Tone

Three short bursts of tone followed by silence; indicates that the feature activated, deactivated, or canceled has been accepted.

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