Patent ID: 7068150

Claim:
A system for sending a power down signal from an Uninterruptible Power Supply (UPS) to a system receiving AC power from said UPS comprising: circuitry for coupling said power down signal from said UPS to an input of a modulating circuit having a power line carrier protocol, said modulating circuit generating a modulated power down signal; circuitry for coupling said modulated power down signal to an AC power cable coupling said AC power from said UPS to said system; circuitry for coupling said modulated power down signal from said AC power cable to a demodulating receiving circuit having said power line carrier protocol, said demodulating receiving circuit regenerating said power down signal; circuitry for coupling said power down signal from said demodulating receiving circuit to power down circuitry in said system for controlling a power down sequence for said system; determining if a primary power source to said UPS meets an acceptable quality; and switching from said primary power source to a secondary power source in response to said determining step and generating said power down signal.