link cable pinout

I am looking for the link cable between two "riding hero" cartridges for my NeoGeo's. It's basically two 3.5 jacks but I have no idea of the pinout. If someone can help...
I don't have the pinout, but my guess is that it's simply 1:1 wired, but with the two front pins (not the larger part at the back, usually GND) crossed.. so the cable that goes to the middle one on one side goes to the bottom on on the other.