Communicating with Honeywell Home T3R 7 Day RF Programmable Room Stat

[rowanbradley]

Has anyone been able to communicate with the Honeywell Home T3R 7 Day RF Programmable Room Stat using RTL433 (or any other similar program using an SDR). To be specific I need to communicate with the receiver of this system, i.e. to send a signal which will open or close the attached zone valve. The Honeywell website says that it uses "reliable, encrypted, two-way wireless communication". Has anyone been able to work out what this encryption algorithm is, or what frequency and protocol is used?

Thank you - Rowan

[ProfBoc75]

Hi @rowanbradley : not sure if it's relevant, but I found 2 github repositories around rf and Honeywell and both are linked.

evoGateway and ramses_fr , the last is providing library for evoGateway. This requires a specific hardware cc1101 with evofw3, probably to be able to decode the encrypted frames. evofw3 is an opensource alternative to the HGI80 from Honeywell.

I can't say the effort to port that to rtl_433, but you will need an RF transmitter to be able to send command to the relay, that not possible with rtl_433 which receives only rf signal and try to decode them.

And what we can find from Honeywell Home / Resideo documentations is that T3R is working into ISM band at 868 Mhz.
Could be Sundial RF² 2-way wireless communication ?

If not too late, prefer the other model, T3M, it is compatible with OpenTherm, so easier to integrate, lot of repositories around OpenTherm

Edit: sounds like rtl_433 is already able to decode "Honeywell CM921 Wireless Programmable Room Thermostat" based on Ramses Protocol, could be a starting point for T3R ?