Unknown SIM state

Hi everyone

After having solved the issue regarding 3-in-1 SIM cards described here we replaced all SIM cards and got all devices up and running for approximately a month. Afterwards some of the devices started to fail again, but now we have a LE_SIM_STATE_UNKNOWN status when checking cm sim status. Running AT+CCID returned an error.
Again, there is no way to reproduce the error in our office…

I will check a sensor next Tuesday (3rd of December) and would like to know if any of you guys have some idea and how I could check what the issue is (I do not have a lot of experience with AT commands)?

Thanks in advance

Michael

Hi Michael,
Which carrier are you on?
Are you executing AT+CCID? with the question mark at the end?

Based on the resolution to the previous issue, it does sound like the SIM card is suffering from the humidity again. Is it possible to confirm the SIM cards are rated properly?

BR,
Chris

Hi Chris

We use the IoT solutions of Swisscom, a Swiss phone carrier. The same subscription is used in many of our sensors (not just the one with Sierra Wireless modems) and we do not have any issues with other sensors.

Yes. I connected to the AT serial interface using PuTTY and issued AT+CCID?. But I’ll check it again next Tuesday.

As previously mentioned, we are using the same cards in other sensing units, but I’ll ask our carrier to make sure.

Thanks again for your support!

Michael

Hi Michael,
Could you please also check with your carrier if their SIMs contain multiple SIM applications? Ie, ISIM, USIM and CSIM?

There was an issue with this but in a much newer version of Legato, so I’m unsure if it applies in this case.

BR,
Chris