Abstract: A dual unit diagnostic system for testing the physical status of a multi-pair cable. Each unit comprises connectors which are connectable to the cable wire pairs, and switches that are connected to the connectors, and are also activatable to provide distinguishable conductive pathways between each wire pair. A signal transmission section is connected to the switches, and provides a signal to a selected wires. A signal reception section is also connected to the switches for receiving a signal from distinguishable wires. A microprocessor is connected to the transmission section and the detection section, and which controls the transmission and reception of signals. A display is connected to the microprocessor and switches, and provides information to distinguish various physical wire status conditions based on the reception of the signal at predetermined wires.

Abstract: The present invention discloses a unitary and hand held four conductor test apparatus that is designed to provide signaling operation tests on new or existing telecommunication special service circuits. The apparatus is comprised of circuitry which interconnects LEDs, a switching element and connection terminals. The apparatus terminates PBX dial tie trunk or special service circuit signaling leads at a designated "demarcation point" and it is designed to exercise or manipulate the special service circuit's associated line equipment for testing.