I was having issues getting mobile broadband working on my ThinkPad X1 Carbon Gen 2. My mobile data provider is Mobistar in Belgium.

When my secondary SIM-card (data SIM) was in the X1 Carbon, I would be stuck at the PIN-code entering stage, and then it would eventually fail network authentication. Then all I was left with, was an error message saying that I couldn’t be authenticated by the network.

Eventually Windows 8.1 would ask me to “Insert a SIM / No Service”. Because apparently after entering my PIN-code it would fail to detect the inserted SIM-card, unless I completely shutdown my X1 Carbon and then restart it again.

I had two SIM cards at first:

  • Primary SIM-card: Is a Micro-SIM I manually cut to a nano SIM to get it to fit in my Nokia Lumia 930. With Dolphin 15.

  • Secondary SIM-card: Nano-SIM with Internet Everywhere 2GB.

These are the SIM-card formats for my devices:

  • Nokia Lumia 930: Nano-SIM

  • ThinkPad X1 Carbon: Micro-SIM

These were the combinations I tried:

Micro-SIM cut to Nano-SIM size with Micro-SIM frame ThinkPad X1 Carbon Works
Micro-SIM cut to Nano-SIM size - Nokia Lumia 930 Nokia Lumia 930 Works
Native Nano-SIM with Micro-SIM frame ThinkPad X1 Carbon Fail
Native Nano-SIM Nokia Lumia 930 Works

The solution?

Get a native micro-SIM if you are having problems. Nano-SIMs are only 0.67mm thick, while micro-SIMs are 0.76mm thick. Then there are also differences in the SIM-card chip itself as you can see in the picture below. The black lines are different, and the micro-SIM chip is slightly larger as well. Getting a nano-SIM with plenty of adapters won’t save your day or is not an all-round solution you can use because it appears to be conventient or simple.

![X1C2-SIM-2](](/assets/img/posts/thinkscopes/2014/12/X1C2-SIM-2.jpg) New native micro-SIM which I received.

![X1C2-SIM-1](](/assets/img/posts/thinkscopes/2014/12/X1C2-SIM-1.jpg) Old non-working nano-SIM with micro-SIM adapter frame.

![X1C2-SIM-3](](/assets/img/posts/thinkscopes/2014/12/X1C2-SIM-3.jpg) Notice how the chip of the micro-SIM is slightly larger compared to the nano-SIM. Also the black lines are slightly different. New micro-SIM on left and the old non-working nano-SIM with micro-SIM frame on the right.