Activating SIM card on Elitebook 820 G3

[Michael8181]

I have an 840 G3 with the lt4120 card installed. I see "insert sim" but the SIM is inserted. The SIM is active with ATT. I tried other computers (same model) with the same result. Differnt SIMS, same result. 

When I installed the driver from the CD, the network connection goes away, and leaves and explanation point in device manager. I have to ROLL BACK. But still It doesn't see the SIM, This has been an issue for months, we tried calling ATT and verified the SIM Is active but we CANNOT get this G3 to see the SIM. I feel like I am reinventing the wheel. This should not be this difficult. 

[banhien]

@Michael8181 

It works similar to many phones. Does your provider support the WWAN card on your computer ? Many SIM cards only work on provider network.

Regards