Oh, thanks! Well, that certainly complicates things, and certainly saves me some time. Hmm that’s a bit more challenging. Spending 1k to sniff a canbus is significantly less exciting… but then again so are all my other thermostat options, hrm. ebay saved search for cheap used 482, activated…
Oh gosh. That’s an even more embarrassing miss… you’re right, wrong manufacturer.
The Mitsu units have a diag port that is the same (or similar) on most of them. I’m not sure if was originally intended for consumer-facing add-ons, but it supports all of the same controls that the IR remotes do. You can see an open thread here on the upstream library where some folks have shared photos of where they’ve tapped in.
For Fujitsu, that’s interesting about the indoor/outdoor bus. I would not be optimistic that it’s connected to (or even the same protocol) as what you’d need for the “frontend” controls, but that’s pure speculation on my part.