Powered and Controlled from the USB hub, the relays used on this Devantech board are premium ultra low power 50mW coil types, this means the boards current consumption is less than 100mA with all relays on. It has a low maximum current consumption of approximately 90mA with all relays on. The relays are SPCO (Single Pole Change Over) types. The normally open, normally closed and common pins are all available on the screw terminals.Installation instructions are available from Devantech in the Downloads section. The USB-RLY08 will show up on a Unix based computer as a virtual serial port without the need to install any drivers.