9 ELECTRICAL AND ELECTRONIC APPARATUS AND INSTRUMENTS FOR CONTROLLING LIGHTING, HEATING, AIR CONDITIONING AND ELECTRICALLY OPERATED EQUIPMENT, NAMELY, POWER LINE CARRIER SYSTEMS COMPRISED OF SWITCHES, SOCKETS, PLUGS, DIMMERS, THERMOSTATS, RECEIVERS, TRANSDUCERS, ALARMS, INFRA-RED TRANSMITTERS AND PROGRAMMABLE ELECTRICAL TRANSMITTERS, TIMERS, MONITORS, AND COUPLERS