Remote subscriber control system of a central office digital switching system

摘要

A remote subscriber control system for controlling communications between remote subscriber terminals and a switch includes a remote subscriber transmitter coupled to a subscriber line interface, a switch side transmitter coupled to the switch and a digital transmission path connecting the remote subscriber side transmitter to the switch side transmitter. The remote subscriber side transmitter includes a state change detector for detecting whether or not a state of a remote subscriber terminal has changed, and a state memory for storing state information of the remote subscriber terminal. A dialing number memory stores a dialing number specifying a called terminal. A transmitter/receiver transmits state information and a dialing number, as subscriber control information, to the switch side transmitter and receives control orders from the switch. The switch side transmitter in turn includes an order receiver for receiving control orders from the switch, an output circuit for storing the control orders and outputting them in the same order in which they were received by the order receiver, and a transmitter/receiver for transmitting control orders to the remote subscriber side transmitter and receiving subscriber control information. A memory in the switch side transmitter stores the subscriber control information received by the transmitter/receiver of the switch side transmitter.