@julian-kröhl oh, you have found a really old thread.
I suggest you to go with the binding or with the MQTT gateway.

If you want to use the binding have a look here: https://github.com/tobof/openhab2-addons/wiki

@donny152 The version 2.2 / 2.3 in the binding name represents the code base the binding is developed to. The current code base is 2.3 so this is the way to go. If you're starting out, just use 2.3.

@dbagioni Is there an error message in the log to the time the gateway changes its state to offline?

Have you considered using the binding for OH2 and MySensors?

Please post (copy and paste) the exact error message from karaf console.

Is the Uno registered by Linux? dmesg, lsusb. Please check the spelling: is it ACM0 or AMC0?

@jogant please enable debug output with log:set DEBUG org.openhab.binding.mysensors and post the debug output here. I'll look at it.

@jjk Thank you for reporting back!

@seeers yes, I've located a bug in the expert mode an fixed it recently!

@masmat Just create the org.eclipse.smarthome.mqtt.cfg file. It's not created automatically. mqtt.cfg is not needed for the binding.

@cgrf Thank you for the hint! At the moment I don't have an explanation for that behaviour.