The ISO-P64 has 64-channel isolated digital input board, arranged into four isolated banks. Each input channel use a photo-coupler input which allows either internal power supply or external power selected by jumper. Isolated input channels 0~15 are designed into group A, channels 16~31 are designed into group B, Isolated input channels 32~47 are designed into group A, channels 48~63 are designed into group B. The power supply of the input port may use the external power or the power from the PC side using DC to DC converter. The board interface to field logic signals, eliminating ground-loop problems and isolating the host computer from damaging voltages. The ISO-P64 has one 37-pin D-sub connector and one 40-pin header. The 40-pin to D-sub 37 flat cable is used to fix with the case. The user can connect the digital signal through the second D-sub connector. Each D-sub connector contains 16 inputs channel and 16 output channel.