Data sheet is at http://datasheet.octopart.com/EE-SX6...eet-134124.pdf and it includes a circuit diagram. +12 v goes to the +, 0v goes to -, out goes to +12 v through say a 4k7 resistor, and also to your BoB input, L is left unconnected. The 0v of your psu should also be connected to the 0v on the BoB. Try that for starters, may need to fiddle with the mach3 settings as well. Don't bother with a reed, it will not respond fast enough and will bounce and give spurious pulses. Remember Mach3 only wants one pulse per rev. Have fun.