/etc/ser2net.conf (on the remote device, e.g. RPi @ 192.168.11.90)
==================================================================

  4001:raw:0:/dev/ttyUSB0:115200 8DATABITS NONE 1STOPBIT XONOFF


socat call (on the local device, e.g. Ubuntu)
=============================================

  socat pty,link=$HOME/dev/ttyUSB0,raw,echo=0 tcp:192.168.11.90:4001
