Abstract: A technique for providing telecommunications service is disclosed that uses a test bus to test customer subscriber lines and to provide a connection between a customer subscriber line and transmission equipment, which handles outbound backup calls. This backup transmission equipment can be inexpensively retrofitted into switches and remote terminal equipment in the field. The illustrative embodiment of the present invention comprises: a plurality of customer subscriber lines; a metallic test bus that can be electrically connected to any of the plurality of customer subscriber lines; drop test logic for testing at least one electrical characteristic of any of the plurality of customer subscriber lines via the metallic test bus; and transmission equipment for providing telecommunications service to any of the plurality of customer subscriber lines via the metallic test bus.

Abstract: A technique for providing telecommunications service is disclosed that uses a test bus to test customer subscriber lines and to provide a connection between a customer subscriber line and transmission equipment, which handles outbound backup calls. This backup transmission equipment can be inexpensively retrofitted into switches and remote terminal equipment in the field. The illustrative embodiment of the present invention comprises: a plurality of customer subscriber lines; a metallic test bus that can be electrically connected to any of the plurality of customer subscriber lines; drop test logic for testing at least one electrical characteristic of any of the plurality of customer subscriber lines via the metallic test bus; and transmission equipment for providing telecommunications service to any of the plurality of customer subscriber lines via the metallic test bus.

Abstract: An arrangement for providing signalling to the lines of a telecommunications system employing non-metallic switching crosspoints such as a solid state switching network or time division switching network. In a system employing either type of network, line signalling such as ringing, coin control signalling, wire chief testing, and such other signals which are essentially high voltage signals cannot readily be transmitted through the switching network. The present system as disclosed provides an arrangement employing a common, multiplex highway between one or more signal sources and the line circuits. Operation of a switching element such as a relay in a line circuit selected by the common control completes a metallic path from the source bus to the selected line through closed contacts of the relay. In addition, signals of one or more different types may be multiplexed within a signal cycle to produce signals to a number of lines during the period when one line is being signalled.