Mitsubishi heat pumps

That's frustrating, absent a multi vendor standard it's nice if vendors just implement a common off the shelf standard protocol which has mature diagnostics tools so it can be easily reversed and documented. In a better world vendors wouldn't be afraid to just share their protocol documentation with customers so the motivated and competent could build their own integration. While sure, most customers shouldn't be fiddling with electronics they don't understand, some portion of customers have relevant training or experience with electronics and software, and I don't know if the benefits of preventing overconfident customers from destroying their gear outweigh the inconvenience to customers who want to modify and get the most out of their purchases.