Abstract: A system and a method for providing electrical power to an optical communication system, in particular a telephone system, between a local or central station and a remote station incorporates a conventional fiber optical cable having an electrical conductor or electrically conductive sheath connected to the local station and the remote station already used for transmitting optical signal. A power source is electrically connected to earth ground and to the electrical conductor or sheath at the local station. A power supply is provided at the remote station and electrically connected to the electrical conductor or sheath and to the earth ground thereat. The power supply receives electrical power from the power source located at the local station via the conductor or sheath and the earth ground, the earth ground serving as a return path. The power supply means can thus provide electrical power to an interface device or any other devices provided in the remote station.

Abstract: A system is provided for monitoring a communications cable for moisture penetration. A line signal generator is connected to a metal armour layer of the cable to apply a line signal to the armour. Changes in the line signal current are monitored to detect the condition of the cable. Moisture penetration can be monitored throughout the length of the cable. The armour layer is maintained at a negative potential with respective ground. This provides an additional cathodic protection to the cable.

Abstract: A resistive fault in an electrical cable is located by applying a DC voltage to one end of the faulted cable conductor. The steady state DC voltage and current are measured at the end of the conductor where the voltage is applied. Simultaneously, the DC voltage is measured at the other end of the cable. The voltage is then reversed in polarity and the measurements repeated. Several repetitions of this procedure at each end of the conductor yields sufficient information to compute the location of the fault with reasonable accuracy. The procedure is carried out using two computer-based units, one at each end of the cable, with the two units communicating over the conductor under test.