Patent ID: 8464081

Claim:
A method, the method comprising: determining, by a power source equipment that delivers power to a powered device via a communication cable, a time characteristic of an on/off cycle of an AC signal that is received from said powered device via said communication cable, said AC signal having a defined cycle frequency, said determined time characteristic of said on/off cycle being characterized by a first time period during which said AC signal is turned on and multiple cycles of said AC signal are received, and a second time period directly following said first time period during which said AC signal is turned off and no cycles of said AC signal are received; and determining, by said power source equipment, a message communicated by said powered device, wherein said message is determined based on a combination of said determined time characteristic of said on/off cycle of said AC signal and a plurality of on/off cycles of said AC signal having said determined time characteristic that are received from said powered device.