Before starting, make sure to authorize your device on Linux. An option is to create a persistent UDEV rule for each device. For example, the following approach apply mode "0064" for the device specified by 'serial', 'idVendor' and 'idProduct' attributes:Code: Text [Select][+][-]# create a new dev rule based on some constantsecho 'SUBSYSTEM=="tty", ATTRS{serial}=="A1004chl", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", MODE="0664"' | sudo tee /etc/udev/rules.d/50-usb-serial.rules > /dev/null # reload rulessudo udevadm control --reload-rules # re-add all devicessudo udevadm trigger # testls -al /dev/ttyUSB0 # you may want to reboot your systemsudo reboot
Most distreaux have a dialout group for the serial ports, and users authorised to use them should be a member.
The solution was: sudo usermod -a -G dialout $USERand to log off and log in again.
I did not know how to find out, if device '/dev/ttyS0' is owned by user group 'dialout', so I just tried it and it worked :-)
Thanks to all who helped me.