My fresh Ubuntu 14.04 box was able to detect an USB modem and successfully connected to internet, though I found connection is sometime shaky. But the joy lasted only few days. Now, If I remember correctly, after having a regular system update the system is no more able to detect the USB modem. However the device is listed in the
lsusb result. In the Network Management menu, I can't see the Enable Mobile Broadband option any more.
On the other hand, My laptop that also running Ubuntu 14.04 can still successfully connect the device to internet. Any diagnostic steps, suggestions are highly appreciated..thanks