I'm not an expert with this, only do some small soldering jobs to keep my gear running etc.. however, from my experience a simple binary footswitch would be TS only. I don't; see why AKAI would be any different.. so even if there are 3 pins the extra is likely doing nothing. You could check the circuit board to see if it's connected to any traces and investigate where they go.. but chances are you won't really need to.. one possibility is that the extra is just being used for stability. if there are 3 pins the original jack is probably just a TRS for some reason.. maybe compare it to a TRS jack and if they're the same you can use it instead.. i bet you would still be able to get by with TS too