Here's our local copy of the GP68 User's Guide. The original is from the support pages of Condor Communications.
Take a look at the Cloning Cable pinout.
There is also a Programming Cable available. Its only use is for aligning the radio with the proper RSS. The RSS has NO other function than to service the radio, it is not for programming modes, editing repeater offsets, changing the scan list, changing frequencies, magically opening the bandwidth, etc., etc. You cannot program anything to the radio. When you read it you only see some very basic information (bandsplit and model number), that's it!
If you are looking for detailed information about programming the GP68 from the keypad, take a look at the manual for the AP73 (below). The AP73 is basically the same radio as the GP68 with a bandsplit limited to the Amateur Radio band.
Check here for the AP73 User's Guide.