Abstract: A wired logic PBX switching system is disclosed in which a camp-on circuit is used to provide automated call hold service. A station user places an existing call on hold by flashing the station switchhook contacts and dialing a predetermined code. The dialing of the code disconnects the station from the first call and places the trunk circuit serving the first call on hold. A second call may then be placed from the station. Upon termination of the second call, the hold condition is removed from the trunk circuit and a connection is reestablished from the trunk circuit to the station.

Abstract: A PBX switching system is described in which a queue is used to provide sequential serving of attendant directed calls. This is accomplished by sequentially storing the identity of the calling circuit for each newly arrived attendant directed call in an attendant queue. When an attendant position becomes available, the calling circuit identity stored longest in the queue is used to directly select the associated calling circuit and to connect this circuit to the attendant.