If using the PLC transmitter with the Steffes microprocessor based heating equipment and utilizing the automatic room temperature set back option, the addition of a signaling device is required to initiate the set back time. This signaling device connects to the ”R” and ”E” input positions of the terminal strip in the transmitter. When the transmitter receives the set back signal, it sends that signal, wireless, to the heater(s). The heater(s) respond by maintaining the set back temperature programmed into them. A closed switch indicates room temperature set back is enabled.