Patent ID: 8258649

Claim:
A method, comprising: configuring a first communication module coupled to a Heating, Ventilation, and Air Conditioning (HVAC) power distribution medium to use signals that propagate between an Alternating Current (AC) domestic power distribution medium and the HVAC power distribution medium, wherein the signals are modulated according to a modulation scheme that enables direct uninterrupted propagation from the AC domestic power distribution medium to the HVAC power distribution medium; configuring a modulation scheme of a second communication module coupled to the AC domestic power distribution medium and configured to provide signals used by the first communication module according to the modulation scheme that enables direct uninterrupted propagation from the AC domestic power distribution medium to the HVAC power distribution medium; wherein said configuring the modulation scheme of the second communication module comprises selecting at least one pair of subcarrier frequencies for Frequency Shift Keying (FSK) modulation from a plurality of subcarrier frequencies used for Orthogonal Frequency Division (OFDM) modulation.