The PCI-OPTO32B board has 32 optically-coupled digital I/O channels consisting of 8 outputs and 24 inputs. Each channel is electrically isolated (1000 Volts) from the PMC host processor board. Change-of-State Interrupts allow for an interrupt to the PCI host to be generated from any level change on any input. Built-in-self-test, selectable debounce times, input pulse counter, and I/ O voltages to 50 Volts makes for a versatile digital interface board.