The ISO-C64 has 64 channels of optically isolated digital outputs, arranged into four isolated banks. Each digital output offers a darlington transistor and integral suppression diode for inductive load. Isolated output channels are designed into group A, B, C, D. The power supply of the output port should be use the external power. This board interface to field logic signals, eliminating ground-loop problems and isolating the host computer from damaging voltages.