I have a problem with gsm (3g, LTE) modem. I use Ubuntu 16.04 on Lenovo Thinkpad x240. Since I started using this laptop gsm modem had been working great. Yesterday I've noticed that it's not working. There was no gsm signal power indicator only standard WiFi indicator. And I couldn't connect to internet. I restarted network-manager with: sudo service network-manager restart I got message that gsm (mobile) connection was established. But gsm indicator didn't show up, and still I couldn't connect to the Internet. Restarting system helped. After restarting system I can connect using gsm modem but signal power indicator still is not present. There is only WiFI one. Unfortunately after closing laptop (system in sleep/suspend mode) modem stops working. To make it work I must restart Ubuntu. I haven't installed any new software or made any changes in system and system settings recently. I think that gsm modem problems could have started after one of Ubuntu updates.
I've installed modem-manager-gui. I can send and receive sms messages without any problem. I still cannot connect to the internet after system sleep/suspend. Now internet works after network-manager restart. But still there is no gsm signal power indicator.
Now gsm modem works without any problem. But still there is WiFi power signal indicator instead of gsm one.