On a linux flavour of tcpser:

What log level do you tcpser running at? And is it tracing?  Turning
logging to verbose/debug (-l 7) and trace some things with the -tis.  Force
tcpser to dump its output to a file with > output.txt

ie:
tcpser -d /dev/ttyS0 -s 38400 -l 7 -tsSiI > output.txt

You might need to add &1>2 to the end of out output.txt (not too
sure since I don't have access to my stuff atm).

Let it run and when it fails, check the output.txt for what happened.

You can also tail the tcpser and see the info as tcpser is running in realtime.

Cheers,
c

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