This 24-Channel USB relay board has a modular USB interface, compatible with Digi XBee modules, as well as Ethernet, Wifi, Bluetooth, RS-232 and other communication options. This video shows the UXP expansion port, with the ability to monitor high-resolution 12-Bit Analog to Digital Converters, Contact Closure Inputs, and Potentiometer Outputs. This controller is expandable to control more relays.