I tried to wire the touch plate to the PBX-RF board but when I plugged a stereo phone plug into a mono phone jack, the "Digitize" light in the "Diagnostics" window stays on. Do I need a mono phone plug or can I cut the tip off the stereo phone plug? In the "Input Signals" dialog box, I set the "Probe" to enabled, port 1, pin 13, and active low. I set the X, Y, and Z Home Switches to enabled, port 1, pins 10,11, and 12, and active high.