I’ve been trying to get hold of a specification of the communication protocol for my heatpump and today IVT, the manufacturer of my heatpump, gave me a call. I’ve not received the protocol yet, but what they did tell me sounds promising.

I’ve had quick a look at the communication protocol and to my suprice, it is a very simple protocol. As far as I can tell, all commands are nine bytes in total; stx, cmd, six bytes of data and the checksum, which is the xor:d value of the data.

It’s hardly worth the trouble to reverse engineer the protocol since there already is a program available to read the data I want, but it is fun none the less ;)

I’m such a tech-freak :P