Remote line monitoring for extension phones in distributed telephone network

摘要

The system has call status information generated by the PBX (32) transferred back to the central office (12) via trunk (11) and rerouted to a remote location on central office line (52). The call status is processed and displayed on an indicator (58) on a display console (56) at the remote location (50). The communication channel (52) has two separate lines, one for digital status information and one for analog voice traffic. Alternatively a single data/voice channel is used with time division multiplexing or bit-robbing to multiplex voice and data. Alternatively a computer is used to implement control functions and voice functions are implemented using the phone. The computer provides call features, like lists of incoming calls, calls in progress and free lines.