Patent ID: 6986071
Filing Date: 2006-01-10
Classification: H04L

Abstract:
1. A power supply subsystem for use in a local area network (LAN), which includes a plurality of LAN nodes coupled to a LAN switch by communication cabling, the cabling including multiple twisted wire pairs connecting the plurality of nodes to the switch for providing data communication among the nodes, the power supply subsystem comprising: a direct current (DC) power source, which is operative to supply DC power to at least one of the nodes via the communication cabling over at least one of the wire pairs substantially without interfering with the data communication; a signal generator, which is operative to generate a periodic time-varying signal and to couple the time-varying signal into the at least one of the wire pairs superimposed onto said supplied DC power; and a control unit, which is operative to sense a time-varying voltage on the at least one of the wire pairs due to the time-varying signal generated by the signal generator, and which is further operative, responsive to the sensed time-varying voltage, to control the DC power supplied to the at least one of the nodes by the DC power source.