Abstract: Apparatus for controlling distribution of d.c. power to a plurality of remote d.c.-powered LAN transceivers, which includes a plurality of primary d.c. power supplies and at least one backup d.c. power supply, all having means for connection to a source of electrical power to provide output d.c. power independently of each other. A plurality of electrical switches are each operable in a first mode of operation to connect one of the primary power supplies to at least one set of output terminals for connection to a remote transceiver. Comparator circuits compare the output voltage at each of the primary power supplies to the output voltage at the backup power supply to indicate a failure condition at one of the primary supplies. Circuitry is responsive to a failure indication for operating one or more of the electrical switches in a second mode of operation in which at least one set of output terminals is connected to the backup power supply.