Just some photos of my XAC installation
First off: the wiring diagram; in case it helps someone else
I wanted a relay between the button I use to open the garage door and the XAC (better safe than sorry) and figured the jumper position of S3 needed to be in first slot, in order to generate voltage output
Then I wanted to hide the antenna… first concidered 3d-printing a shell but I ended up placing it inside the wall
Now all I need is some paint 
If you’re driving an external relay then yes, S3 needs to be set like you have it. BUT if you remove S3 and throw it over your shoulder, then the 3 relay wires out of the xAC become entirely disconnected from the power supply, that is to say they are already relay isolated and just dry contact closures.
It’s perfectly safe to connect directly to button circuits as long as you remember to throw away S3 before connecting it, but what you’ve done is also totally fine.
Embedding in the wall looks cool, will be great once painted!
