Ok, now I'm tracking. That's some good info and I now have everything working. The key for me was understanding this isn't a proprietary GGG thing and that I can use any connections. After some thinking I came up with a solution.
For anyone else who may stumble across this thread looking for the same info, hopefully this is helpful. The pins needed are the 5v\ground and the ABCD pins. In my case I had compatible pins, but a possible method to get some pins would be to purchase a zero Delay encoder like this one:

Make sure it comes with all the wires. These cost way less than the GGG cable, but will require you to do some work, but as a bonus, you now have another encoder. You may need to modify the plugs, I had to sand mine down so they were smooth on one side so I could plug in multiple pins. A picture says a 1,000 words so hopefully this answers any questions you might have:


Good luck!