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.
