Serial Port for Root Only

[Brendan Jones]

On 04/30/2011 09:38 AM, Mike Dwiggins wrote:
>>>
>> Try adding the user to group tty
>
> Same Result.
>
Ensure that the user can read/write your device /dev/ttySX

You might want to consider writing a udev rule so these permissions 
persist after reboot.

Plenty of docco out there - one such example:
http://www.libelle-systems.com/free/wine/serial_port_access.html