root@fic-gta01:~$ lsof | grep ttySAC0
root@fic-gta01:~$ echo "1" > 
/sys/bus/platform/devices/gta01-pm-gsm.0/power_on
root@fic-gta01:~$ dmesg | tail -n 1
<6>gta01-pm-gsm gta01-pm-gsm.0: powering up GSM, thus disconnecting serial console
root@fic-gta01:~$ chown uucp.uucp /dev/ttySAC0
root@fic-gta01:~$ cu -l /dev/ttySAC0
Connected.