Simple RS232 & IP control

It looks like the binding is not sending the escaped characters \n and \r
Have you tried to change the character set and indicated in the serial binding docs.

The solution is there:

There is an updated binding in the SNAPSHOT release that should work OR you can change the CHARSET as indicated in the thread.

You can update to snapshot or wait a bit for OH 2.3 stable which is not too far away I understand.