Configuration for OpenHAB
The Gateway communicates via MQTT and publishes and listens to a number of topics. You can integrate this into OpenHAB with the help of a MQTT server and some automation rules.
You can now just use the MQTT Discovery feature to integrate the Gateway into OpenHAB. See the HA Binding [2].
There are users that have integrated the EMS Gateway with OpenHAB without the Auto Discovery. See the topic on the OpenHAB forum [1] for an excellent configuration example.
MQTT structure
See Proddy’s EMS-ESP Wiki [3] for all the details on MQTT.