I’ll try to play around with the AT commands, but there is something I don’t understand:

After my SIM connected I am trying to get my current network:
AT+COPS?
which results in
+COPS: 0,0,"Telekom.de heyah",7

That’s great.

But when I do
AT+COPS=?
to list all available networks, the modem dies. GUI tells me the USB modem is unavailable and the “Internet” LED on the front turns off. Ping is working without problem - so something is odd here.

After a reboot everything is fine again. The same happens when I send AT-COPS=? by using socat /dev/ttyUSB2