An Ethernet device power transmission system includes an input transformer,
an output transformer and a pair of twisted pair conductors. The input
transformer includes a pair of primaries for connection to a source of
Ethernet data. The input transformer also includes a pair of secondaries,
each having a center-tap. A first twisted pair conductor is connected
across the first secondary, a second twisted pair conductor is connected
across the second secondary and a DC-bias is provided between the
respective center taps of the first and second secondaries. At the local
end, the output transformer includes a first and second center-tapped
primary and a first and second secondary for connection to the load
device. The first and second primary center taps are connected to a power
processor for extraction of DC power.