It’s 5 pins an the colour scheme on the cable is identical to the colour scheme on pexp1‘s cable. I am tempted to try hooking pexp1 up to pams pro! 🤣
-- nemoy

I would probably try tracing them with a 'scope or logic analyzer first, just to be sure...

(The signals would be always-present if it is the same, +5/run/x24/midi/gnd)