Abstract: A power distribution apparatus for distributing electrical power includes circuit breaker modules and remote operated devices mounted separately in a panel. The devices may be relays, circuit breakers, meters, dimmers or other devices for controlling a circuit. An I/O controller board is connected to the remote operated devices and controls those devices through a data rail. A control module may interface with the I/O controller board and may also interface with other I/O controller boards and with one or more networks. A serial communications line connects the I/O interface board with a number of remote operated devices. A separate select line runs from each remote operated device to the I/O controller board. To operate a particular device, the I/O controller board asserts the select line of that device, causing the device to listen for messages on the serial line. The relay executes commands contained in a message only of the select line for that device is asserted.