There is provided an inductive power line data coupler. The coupler
includes (a) a magnetic core having a high magnetic permeability at a
data communication frequency and being configured to allow a power line
of a power distribution system to be routed through the magnetic core to
serve as a primary winding, (b) a data signaling circuit that provides a
secondary winding through the magnetic core for coupling a data signal
between the power line and a communication device, and (c) a choke coil
coupled to the data signaling circuit for creating a flux-canceling power
frequency current opposite in direction and comparable in magnitude to a
power frequency current. The coupler may also include a circuit for
sensing a level of current in the power line.