CAS - technical definition

Centralized Attendant Service. A PBX feature that allows the consolidation of multiple console operators for a number of PBXs.Thereby, a single group of operators can perform all attendant functions, including placing calls, answering and extending calls, and establishing conference calls. CAS will work whether the PBXs are distributed across a campus, a metropolitan area, or even a wide area, as long as the PBXs are networked over dedicated circuits.
Channel-Associated Signaling. A signaling and control technique by which the signaling and control information associated with a communications channel is carried within the channel, itself, or in a separate channel permanently associated with that communications channel. See also CCS, NFAS, and signaling and control.

See CAS in Computer