Gavin i dont have a CGX mount but i suspect its similar in nature to my Celestron Evolution mount. I would connevt the usb cable from laptop to your hand controller not the mount. If you HC has a snall telephone like port then you need a usb to serial adapter and then either you can make or buy the serial to HC cable. If your HC has a micro usb port then you can connect via usb direct.
This thread maybe of help
http://www.iceinspace.com.au/forum/s...d.php?t=155803