a data and power transmitting / receiving system applicable to a home automation system . plural terminal units and associated communication units are connected via a common signal bus . each terminal unit may operate an electrical load to be controlled remotely , and may include control switches for operating such loads at a number of remote locations . each communication unit generates an n - bit data signal , each bit corresponding to the desired function of a corresponding terminal unit . a sync signal is combined with the data signal in time sequence such that the respective communication units can identify which signal operates which terminal unit . the sync signals also can supply dc power to ther respective communication units .