An apparatus may comprise processing circuitry, a first pair of terminals, and a second pair of terminals that are electrically connected to a cable. The processing circuitry may provide a periodic signal including pulses to the first terminal. The duration of each of the pulses may be at least double the time of travel of the pulses along the length of the cable. The processing circuitry may also detect a fault in the cable responsive to a received signal at the second terminal responsive to the periodic signal.