Power line communication interference preventing circuit

Claim 1

A power line communication device, comprising: means for connecting a transmitter in signal communications with a power line, said connecting means comprising a transformer having a first and a second winding, said second winding of said transformer being connected to said transmitter, said first winding of said transformer being connected in signal communication with said power line; means electrically connected to said connecting means for tuning said connecting means to provide a low impedance circuit path between said power line and ground potential for a preselected frequency signal when said second winding is shorted; means for shorting said second winding, said shorting means being switchable between a shorting position and a nonshorting position; said shorting means comprises a switch connected between termini of said second winding, said switch being operable between a first state and a second state, said second state being effective to short said second winding; and means for controlling said switch, said controlling means being associated with said transmitter to short said second winding when said transmitter is not transmitting.