Thanks for your fast reply. That sounds easy. And you think that the communication between sensor nodes and Gateway are still possible via wired RS485? I tried to find an example on this site for sending Information from Gateway to sensor nodes. (via SendMessage ?) For example I like to Switch on/off an light that is connected to an relay board at my sensor node. Communcation Flow: OpenHab2 --> MQTT --> Gateway --> RS485 --> Sensor Node --> Relay Board Currently I have an working RS485 Connection between my Arduino Uno's with the use from SoftwareSerial library. During my testings I realized, that the message that I triy to send "Hello" will be sent to the other arduino char by char. Is that true? Because I tried to raise up an pin on HIGH with "if(msg == "Hello")..." But it doesn't worked. Will the sendMsg method from the MySensor library handle this out of the box? Regards, Simon