Acoustic marking of direction of arrival of subscriber calls in PBX - has content of storage locations allocated to various circuits interrogated and control signal is derived

摘要

The PBX is centrally controlled, and the switching necessary for a connection build-up depends on the result of a continuous interrogation of connection and/or subscriber state stores. EAch subscriber unit has a call circuit controlled by a central call control device. A group allocation of the call direction (e.g. external) of a calling subscriber is derived from the content of storage locations permanently or temporarily allocated to subscriber circuits connecting circuits and connection paths. A control signal is derived for the signal delivered by the call control device.