Abstract: The present invention provides a system for commanding and monitoring one or more electrical devices. The system includes two or more communication modules or controllers, including a primary controller connected to a DC power source that transmits voltage pulses over a single conductor, and one or more secondary controllers that transmit current pulses over the single conductor. The communication modules or controllers each include a bi-directional communication circuit and a microprocessor. The present invention also provides a method for transmitting and receiving communication signals and power, where the voltage pulses sent by a primary controller can be used to power the secondary controller and one or more electrical devices connected to the secondary controller.