Q: I have a Capcom IO board that I am using to convert JVS to Jamma. Is there a pinout I can use as a reference?
A: There is! Thanks to Solvalou, it is readily accessible. If you need voltage for 3rd and 4th player controllers, please use pins 32 and 31 - they provide about 12 volts of power:
Pinouts of CPS-2 and CPS-3 kick harnesses are the same as the 4 player Naomi Capcom IO, so they are just plug and play.