After looking for the pin outs for this unit discovered it was made by Mars Money Systems and that they had the technical sheets for this product.

pin outs for MS111

  1. Coin 1 inhibit
  2. Coin 2 inhibit
  3. Coin 3 inhibit
  4. 0V
  5. +12V
  6. Coin 4 inhibit
  7. Coin 4 Output
  8. Not used
  9. Coin 3 Output
  10. Coin 2 Output
  11. Not used
  12. Coin Output 1
  13. Output Common (12V)

Looking at these technical specifications, you can see that the output is pulsed (12V) for every coin accepted.

You can work out which coin by dropping through a selection of coins, and see which "Coin Output" pulses.

To get the coin mech to accept coins, you need to connect the inhibit lines to GND. Each one corresponds to particular type of coin.

This would work well with the cheap input method, using a game pad as an input device.