LX8/ID modules have discrete circuits that can be used to detect contact sense, DC Volts, Current flow, AC sense, threshold voltage or whatever circuit you can dream up. Detection circuit is opto isolated and allows status feedback to your computer. See circuit examples in the drawing to the left. There are 8 circuits per module. Specify what circuit you would want on the prototyping section of the board. 20 Pin header connector for I/O.