Smart appliances

A communications apparatus for communicating data between Smart Appliances comprising:

• a modulator for modulating said data for communicating from a first of said Smart Appliances to a second of said Smart Appliances on to a carrier frequency signal;
• a signal injection device for injecting at said first Smart Appliance said modulated carrier frequency signal on to a circuit comprising a first and a second conducting path, the first of said conducting paths comprising at least one live wire and a neutral wire, and the second conducting path comprising a ground wire, wherein the ground, live, and neutral wires connect said first and second appliances to a power circuit;
• wherein said circuit comprised of said first and second conducting paths is completed, at least at one end, by connecting the neutral wire to the ground wire through a capacitor in series with a damping resistor, these components having a low impedance at said carrier frequency while having a high impedance at the power line frequency;
• a signal extraction device for extracting at said second Smart Appliance said injected modulated carrier frequency signal from said circuit comprised of said first and second conducting paths;
• wherein each signal injection and extraction device comprises a closed magnetic circuit of magnetic material through which pass at least one live wire and the neutral wire feeding power to said respective Smart Appliance, to form a primary winding equivalent to at least one turn;
• wherein each signal injection and extraction device further comprises a multi-turn secondary winding on the closed magnetic circuit, whereby the secondary winding is electrically isolated from the live and neutral wires, and is used to inject and extract, respectively, said modulated carrier frequency signal;
• and
• a demodulator for demodulating and decoding said extracted modulated carrier frequency signal to obtain said data at said second Smart Appliance.