ower management & control unit 2038 via the combiner 2036 (FIG. 10A) or from similar circuitry in the embodiment of FIG. 11A. Alternatively, it may sense a control signal transmitted thereto, such as a signal transmitted via the communication cabling from the power management & control unit 2088 via the power supply interface 2086 (FIG. 10B) or from similar circuitry in the embodiment of FIG. 11B.