LT-33222-L com port problem

This is more of advise rather than a question.
I had some issue with the LT-33222-L trying to communicate via the com (TTL) interface. I initially believed it had to do with the com port controller. The reason is that I initially used a controller which had intermittent problems. I ended up with an Aduino UNO configured as a USB to Serial converter, which works very well.
I somehow managed to miss-configure or corrupt the configuration on the LT.
When ever I reset the device, I was able to sent commands for a very short time to the LT but after that it did not respond to any commands. To fix this I sent direct after a button reset the “password” and the AT+FDR which is a factory reset but preserves the keys. All works well now as expected.