1. The overall length of time required to establish a circuit-switched call between users.
2. For data communication, the overall length of time required to establish a circuit-switched call between terminals; i.e., the time from the initiation of a call request to the beginning of the call message.
Note: Call set-up time is the summation of: (a) call request time--the… (Read More →)

A station or address designator represented by a combination of characters or pronounceable words that is used to identify such entities as a communications facility, station, command, authority, activity, or unit.

In common-channel signaling, the effect on a traffic circuit of the arrival at a switching center of an abnormally delayed call control signal relating to a previous call, while a subsequent call is being set up on the circuit.

A switching system service feature that allows a switch attendant to talk privately in either direction on an established call.

The call through test confirms capabilities of the interface relative to an actual or simulated call: Basic call set-up; sequential, acknowledged transmission of user data; and call termination.

A procedure that permits an entitled user to be informed about the routing of data for an established connection, identifying the entire route from the origin to the destination.
Note: There are two types of call tracing. Permanent call tracing permits tracing of all calls. On-demand call tracing permits tracing, upon request, of a specific call, provided that the called… (Read More →)

A switching system service feature that allows the calling or called user to instruct the local switching equipment or switch attendant to transfer an existing call to another terminal.
Note: Call transfer may be available on a call-by-call basis or on a semipermanent basis.

In telephony, a service feature that provides an indication to a terminal already engaged in an established call that one or more calls are awaiting connection.

A signal sent in the backward direction indicating that a call cannot be completed because of a time-out, a fault, or a condition that does not correspond to any other particular signal.

A call control signal sent by the called terminal to indicate that it does not accept the incoming call.