An interface for the RAMSES RF protocol, as used by Honeywell-compatible HVAC & CH/DHW systems.

ramses, evohome, sundial, chronotherm, hometronics, airios, bdr91a, evohome-rf, hgi80, itho, orcon, ramses-rf, resideo
pip install ramses-rf==0.16.24


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ramses_rf is a client library/CLI utility used to interface with some Honeywell-compatible HVAC & CH/DHW systems that use 868MHz RF, such as evohome, Sundial, Hometronic, Chronotherm and many others.

It requires a USB-to-RF device, either a Honeywell HGI80 (somewhat rare, expensive) or something running the evofw3 firmware, such as the one from here.

It does three things:

  • decodes RAMSES II-compatible packets and converts them into useful JSON
  • builds a picture (schema, config & state) of an evohome-compatible system - either passively (by eavesdropping), or actively (probing)
  • allows you to send commands to evohome, or monitor for state changes
  • allows you to emulate some hardware devices

The simplest way to know if it will work with your system is to identify the box connected to your boiler/HVAC appliance as one of:

  • R8810A: OpenTherm Bridge
  • BDR91A: Wireless Relay (also BDR91T)
  • HC60NG: Wireless Relay (older hardware)

Other systems may well work, such as some Itho Dallderop HVAC systems, use this protocol, YMMV.

It includes a CLI and can be used as a standalone tool, but also is used as a client library by:


git clone
cd ramses_rf
pip install -r requirements.txt

The CLI is called

python monitor /dev/ttyUSB0 -o packet.log