Though there all "all in one" Multi-function devices out there
The converter and the Auto Transfer switch have very little to do with each other..
The job of the ATS is to select between a built in Generator and Shore power. Or some other source of power and shore/generator power (IE INVERTER)
The job of the CONVERTER is to make battery voltage out of 120vac.
The only "Relation" is the ATS chooses Shore or Generator
IF you do not have a generator you do not have an ATS but the converter still works.. Just like a fully automated battery charger (Which it is).
Some models are hard wired, Mine is plug in.
Had to replace it a few weeks back (Halloween eve) 3 screws held it in place. one Ground wire, The plug for the Charge Wiz. and two heavy 12 volt cables
One 20 amp 120 volt plug,, and a 25 mile "Turn around" (distance to/from factory round trip) and I was 100% again.