摘要 |
A power supply subsystem for use in a local area network (LAN) includes a direct current (DC) power source, which supplies DC power to at least one of the nodes via at least one of the wire pairs used in communication cabling of the LAN, substantially without interfering with data communications. A signal generator generates a periodic time-varying signal and couples the time-varying signal into the at least one of the wire pairs. A control unit senses 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 responsive to the sensed time-varying voltage, controls the DC power supplied to the at least one of the nodes by the DC power source.
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