Help with ST-4

I recently bought a used ST-4 here, and last night tried it with my older, non-Gemini G11 mount. Everything worked as expected through the "find and focus" step. When I tried to calibrate the mount, however, nothing happened. No movement in any direction. I increased the C1 and C2 settings to their max, and still nothing. The up-down, and left-right arrows on the ST-4 did not move the scope either. The mount hand controller works fine, and, yes, I did plug the ST-4 guide cable into the HC/CCD port on the mount! I noticed that the plug that attaches to the RS-232 port on the ST-4 has only two pins in it. I don't understand how two pins (and I suppose the outer housing of the plug) can provide all the guiding info to the mount. Does that sound like the proper plug for a G11 mount? Am I missing something? Any help would be appreciated! Alex, are you out there?

Thanks,

Steve

The guide cable is definitely suspect. At least 4 wires are needed for opening and closing the switches (relays) for auto-guiding (2 per axis).
Doing a quick search resulted in this:

http://www.nightskyphotography.com/autoguider.pdf


Robert