I ran all my console's into a DB-25 and a data switch box with a b c d channel one box for each video DB9 box's and cables are best for video cables and the DB25 for the controllers.
I had 3 console's and pc connected to mine.
the DC player 1 and 2 ground needs to be seperate I already went down that road I used the common ground for both and it was nuts so do player 1 and player 2 controls with a seperate ground they can still used as a common ground but only per player controls wise.
so all of the buttons and joys on p1 can use CG and same with P2 but dont use a CG that shares both P1 & p2
I also have a toggle switch to swap between D-pad and analog but the analog only work as a digital but that way all DC games are 100% controllable instead of being limited to just D-pad only games.
I also mounted everything in radio shack project box's to keep them safe from moving bumps etc and also dust free.
it also keep the wiring nice on the DB25's instead of having crazy wire's all over and not knowing what goes where.
it can and has been done with pretty much any console in my collection
