Hardware and software to capture and decode the Mitsubishi M-NET HVAC protocol Mitsubishi uses a propriety network called M-NET to interconnect heating and air conditioning units with each other and with control devices like thermostats. Without having access to any proprietary or confidential documents, I have started a project to reverse-engineer both the hardware and the software protocols of M-NET. From time to time I will make available the current status of that project here.