Hi abispac,
My pacdrives do have outputs off and I also had to get one of them recoded by Andy at Ultimarc so that they were able to run in the same machine (the two I bought both had ID 1. I imagine that you might have an issue without the special using a hopper as until MFME takes the signal and starts to control the pacdrive the output will be on and will therefore attempt to pay coins. I'm sure some more knowledgeable in such matters like Wizard will be along shortly and will point you in the right direction.
Pete