Access to serial port

In order to get rid of the error

you don't have +rw permission to access serial port

you need to add your user to the uucp group

> ls -l /dev/ttyS0
crw-rw---- 1 root uucp 4, 64 Nov 12 18:44 /dev/ttyS0

/usr/sbin/usermod -a -G uucp my_username