Permission denied when attempting to open ttyS# in GtkTerm

Question

I'm trying to open a serial port in GtkTerm (downloaded from Ubuntu Software Center), however I'm getting "Cannot open /dev/ttyS0: Permission denied" error.

Ubuntu Version: 14.04

Solution

Add yourself to the dialout group. It has read/reite permission to that device:

sudo usermod -a -G dialout <user>

and restart the session.

(groups command shows your groups)

Comments

[user2364305]

sudo su <user> worked without restarting, just export the display after