I have started to use cu instead of screen as my go to serial console program.
This is my notes in case i forget.
To start a terminal session with baud rate 9600 and ttyUSB0 as serial adapter:
cu -l /dev/ttyUSB0 -s 9600
To exit the session, use the same exit procedure as SSH:
There exist a bug in Debian that will give you a Permission denied error even if you are root. This can easily be fixed by giving read/write permission to everyone.
chmod 666 /dev/ttyUSB0
The bug still exists as of Debian Jessie 16.05.14.