Decoding the messages on the DM port (/dev/ttyUSB0)

How do I decode the messages generated on the DM port (/dev/ttyUSB0)?

You need to have qualcomm qxdm professional

Is there any alternate way?

No, I don’t think so.

There are many open source tools to parse diag messages. Probably the best right now is qcsuper from P1sec which you can find on GitHub.