Comment 5 for bug 889411

it definitely seems to be a NetworkManager problem. Software Center relies on it to detect if the connection is present or not, so if it does not sense your modem connection Software Center believes you are not connected.

Could you please open a terminal and then perform the following actions?

1) Install the latest development version of NetworkManager by running:
sudo apt-add-repository ppa:network-manager/trunk
sudo apt-get update
sudo apt-get dist-upgrade

2) Stop NetworkManager with:
sudo stop network-manager

3) Start to capture the system logs by opening another terminal and running:
tail -n0 -f /var/log/syslog > /tmp/syslog
The command will not stop, it's normal.

4) Return to the first opened terminal. Restart ModemManager (a NetworkManager component) and NetworkManager itself with:
logger "Killing Modem Manager"
sudo killall modem-manager
logger "Starting Modem Manager"
sudo modem-manager --debug 2>&1 | tee /tmp/modem.log.txt
export NM_PPP_DEBUG=1
logger "Starting NetworkManager"
sudo NetworkManager --no-daemon 2>&1 | tee /tmp/nm.log.txt
logger "Starting new connection creation"

Try then to create a new connection (in NetworkManager itself) using the MEZON modem. Don't worry if it does not work, the exact causes of the error will be recorded.

5) Run some quick modem and network tests:
wget http://cgit.freedesktop.org/ModemManager/ModemManager/plain/test/mm-test.py
logger "Starting Modem Manager test"
python ./mm-test.py >/tmp/mmtest.log 2>&1
logger "Starting NetworkManager debug"
sudo python debug-helper.py --nm debug
logger "Getting WPA logs"
sudo python debug-helper.py --wpa msgdump

6) Switch back to the second terminal (the one where you started to capture system logs) and press Ctrl+C. This will stop the capture.

7) Finally, collect some information about your hardware with:
udevadm info --query=all --path=/sys/class/tty/... --attribute-walk >/tmp/udevadm.log 2>&1
lsusb >/tmp/lsusb.log 2>&1

8) Attach the files "/tmp/syslog", "/tmp/modem.log.txt", "/tmp/mmtest.log", "/tmp/nm.log.txt", "/tmp/udevadm.log", "/tmp/lsusb.log" to this bug report.

The procedure is fairly complicated, but it will help us establishing the exact nature of the bug.

Thanks!