The PCIe-IIRO-8 is a x1 lane PCIe isolated digital input and relay output board with Change of State (COS) detection capabilities. The isolated inputs can be driven by either AC or DC and are not polarity sensitive. Input signals are rectified by a diode bridge and applied to the inputs of opto-isolators. A 470 ohm resistor in series provides current limiting. Standard 12/24 AC control transmitter outputs can be accepted as well as DC voltages. The input voltage range is 5V to 24V (rms). To extend the input voltage range, you may connect external resistors in series. The electro-mechanical relay outputs of the PCIe-IIRO-8 are comprised of five form C SPDT outputs and three Form A SPST (normally-open) type. The relays are all de-energized at power-on. Data to the relays is latched. I/O wiring connections for this board are via a male 37-pin D-sub connector. A ribbon cable can be used to connect this card to termination panels.