This is the circuit board plus all parts needed for you to assemble the 8 Channel I/O (8 Relay Version). Please see the product description of the fully assembled 8 Channel I/O (8 Relay Version) for more information.

The board has eight 1 amp SPDT relays and eight opto-isolated inputs controlled by a DS2408 1-Wire chip. The board has an LED on each output to show when it is energized.

The onboard LM78M05 voltage regulator can supply enough current to have all 8 relays energized at once but the voltage supplied to the board should not be provided over long runs of cat5 to minimize loss in the wire.