I am sharing my Comfort integration with Home Assistant. This is a standalone Comfort to MQTT bridge for Cytech's Comfort II Ultra Alarm system with UCM/ETH03 module primarily intended to integrate with Home Assistant (or OpenHAB or other MQTT compatible systems). It can run on a Raspberry Pi and other systems with Python 3 support.
With Home Assistant, you can further extend the Comfort system with more complex logic, inputs, outputs and actions. Using virtual inputs, you can define additional zones in Comfort triggered by any sensor available in your Home Assistant setup. Or vice-versa, having Comfort trigger any action in your Home Assistant setup.
Sorry, I am not familiar with OpenHAB, but it should just be about defining the appropriate topics for MQTT sensors and switches. The should be some guides out there on how to do this. Test with just one sensor, say "comfort2/input1" then activate that input by opening/closing doors or windows in the corresponding zone and you should see some message in the comfort2.py console as well as your mosquitto log and hopefully in OpenHAB. Comfort alarm does not need to be armed for this.