Comment 9 for bug 1564808

After investigations, we found that:
* The "ttyACM3" from the "-f 2" is not working, it's the device name, not the interface name.
* The interface name will only be available when it's connected to the mobile broadband network.

For example, the interface name is ppp0 in the following case:
GENERAL:ttyACM3:gsm:NMDeviceModem:Telit:6 CDC-ACM + 1 CDC-ECM:cdc_acm, cdc_ether:::(unknown):0:100 (connected):0 (No reason given):/org/freedesktop/ModemManager1/Modem/0:ppp0:no:yes:yes:no:--:test connection:74298ac0-52c7-4b28-a6ad-ea4d77f160af:/org/freedesktop/NetworkManager/ActiveConnection/11

ppp0 will be the 15th column, however, it's 11th column in Precise.
We will need to find a more reliable way to get this.