Thanks for the info on the Goodman/Carrier lawsuit - unfortunately the U.S. District Court of Delaware can’t seem to keep it’s documents online either. Fortunately the wayback machine was able to retrieve it.
I just installed an Amana heat pump, and the documentation emphasized that the indoor and outdoor units must be used with the CTK04 thermostat and that CTK01, 02, 03 won’t work. That apparently also has something to do with the lawsuit:
“At trial, Carrier asserted that certain of Goodman’s products - the ComfortNet indoor and outdoor units with one of a CTK01 thermostat, CTK02 thermostat, or CTK03 thermostat (collectively, “the ComfortNet system”) - infringe claims 6, 8, and 13 of the
'004 patent.”
Since this is my first experience with a communicating system (it replaced a 24 year old Trane HP), I was toying with the idea of building a passive bus sniffer and event logger. Thanks to all for posting the information here; if I ever write some Python message parsing code I’ll be sure to send a pull request.