No need to make things overcomplicated. That coin-counter Works fine with 5V DC. Therefore if your IPAC, PAC-DRIVE etc... has a 5 volt output pin, plug or similar, connect the res wire to it and that's it.
After that, i I remember correctly, you have to join the black wire to the coin mech ground wire/switch.... If you still can't solve it, ask me and I'll try to help you.