Gammu not replying anything

Hi,

WHen trying to send ussd code with gammu package ("gammu getussd *143#"), gammu replies only

# gammu -f /tmp/jojo.txt  getussd *143#
Press Ctrl+C to break...

My /etc/gammurc file is :

[gammu]
port = /dev/ttyUSB3
connection = at
logformat = textall

Is there some patch under openwrt to make it work ?