Hi, First post here, so be gentle

I have a Sieg KX3 running via parallel port on Mach3 and had I'm wondering about the probe connection on the machine:
a) Does anyone know the connections of the 1/4" jack on the machine?
b) any tips on building a rudimentary probe (accuracy at this moment isn't important - more just to find out how it all works)
c) any tips on setting up Mach 3 to use the probe

Many thanks in advance for any help given