Why are SIM cards not supported in the LTE Sierra EM7345 modem?

Question

Megaphone

Good day toasters and toasters!
The main question: the SIM card (tele2, beeline, megaphone, mts) does not want to work in the LTE modem Sierra 7345

Water information: I bought this modem on Ali, which has official support for my laptop model (Lenovo Thinkpad). Correctly installed, the drivers also got up as they should. I used the laptop manufacturer's forum to resolve my issue: I re-flashed the modem through the official utility:

everything is ok. But SIM categorically does not want to work (no service). I spent several days on various ways to solve this problem: I read foreign forums, tried different firmware versions (coincidentally, I even reinstalled win after that), but did not solve the issue.
I tried different SIM cards (of different operators) - it's the same everywhere, while the SIM cards themselves are valid and work perfectly both in the smartphone and in my SIM-fi-wi router

when "diagnosing" the connection, it shows the following inscription:

the mobile broadband device is locked with sim pin2. Contact your mobile operator for assistance with unlocking the device

Answer 1

The solution turned out to be very banal: if you look at photos of similar modems, you can see two "mounts" a la like a Wi-Fi module, for connecting two antennas (I have them: orange and blue). I disassembled my laptop, and really saw two antennas that are not connected anywhere (and are sheathed). Once connected - everything worked!
PS and afterword: NEVER insert a SIM card adapter into a SIM port without a SIM ....

Answer 2

and there is nowhere to enter this PIN2?

Answer 3

It is possible to block the modem for only one operator (you need to re-read the description of the lot). There are situations when the number of attempts to enter the unlock code ends and the modem is completely locked.
You should also check the technical characteristics of the modem - whether the frequencies of the RF operators are suitable for it.