This product is a negative-common typed PCI Express bus-compliant interface card used to provide a digital signal I/O function on a PC. This product can input and output digital signals at 12 - 24VDC. It features 32 opto-coupler isolated inputs (compatible with current source output signals) and 32 opto-coupler isolated outputs (current source type). You can use 32 input signals as interrupt inputs. Equipped with the digital filter function to prevent wrong recognition of input signals is provided and output transistor protection circuit (surge voltage protection and overcurrent protection).