Repeater with selective repeat

A repeater device for selectively repeating command signals in a power line communication system, the repeater device comprising:

• an input port to receive command signals for controlling electrical devices in a power line communication system, each command signal having a location code representing a location in which an electrical device is installed,
• a code entry circuit to enable a user to select one or more location codes;
• and
• an output port to transmit command signals having a location code that matches the selected code.

A switch device having filtering capability for use in a power line communication system, the switch device comprising:

• a switch circuit connected between an input port and an output port, wherein the output port is for connecting to a load, and the input port is for connecting a power source to power the load and for receiving command signals for controlling power to the load;
• a repeater having a first end coupled to the input port and a second end coupled to the switch circuit, wherein the repeater responds to the command signals and activates the switch circuit to provide an electrical connection path between the power source and the load;
• and
• a filter circuit connected in series between the switch circuit and the load, wherein the filter circuit presents a high impedance to the command signals to prevent the load from attenuating the command signals.

A method of improving noise immunity in a power line control system comprising:

• storing in an electronic memory selected codes representing locations of electrical devices on the power line control system;
• receiving commands having location codes from an input power line of the power line control system;
• and
• repeating only the received commands having the selected location codes.