That's definitely a very early PDA setup. They moved to the more "modern" diamond shaped J-boxes not long after that, and I agree you'd probably be hard pressed to figure out what works correctly with your particular board and firmware revision. Jandy, of course, documents none of this. The pool builders that know don't share their secrets.
I ended up just removing my whole PDA setup because I couldn't figure out which parts I needed and I wasn't dumping tons of money into it. At least I can control the system again now and change programming. If you're truly sold on the PDA idea, you may be able to find a complete used "modern" PDA setup (PCB, J-box, and PDA) for relatively cheap if you look on fleabay long enough.