Now that I have everything I need, I decided to connect everything and see if it worked. Since my next move is to analyze what’s going on between the RAC adapter and my air conditioner, I made a simple breakout board for easy debugging.

And here is my full setup, ready for a test:

After setting up the DIP switches according to the manual, performing a factory reset of the central station, and waiting 10 long minutes for it to finally boot up, here’s the result.