Greetings.
Background:
We have a custom device, that uses the nRF9160 as a Modem, with Modem OS 1.3.4 and a sightly modified "Serial LTE Modem" FW. One of our Devices was sent to a customer and he put in his SIM card.
With this SIM Card inserted we get a CME Error 13 - SIM Failure on the at+cpin? command. The SIM appears to be working though, as it's recognized on the customers Phone. Since The Device is at the customers site on a different continent, we can't really test with it, so I wanted to gather some general Info about this.
To be clear, in our Lab we've tested various SIMs with all kinds of Pins and APN settings, so we know our FW should generally configure the Modem correctly.
Now the questions:
Do you know, when CMEErr 13 can occur? We've seen the Modem report it also when the SIM is not inserted at all, but what are these other failures? Are they always HW related?
Could this be a timing thing? Would it be wise to add some retries for the at+cpin command? if so what would be an appropriate time between retries?
As the problematic setup is at our customer in a different country, we don't really have the possibility to just flash and try about, that's why I'm asking this barrage of questions, so we can so our best to counteract this in the future, if possible.
Best wishes,
MaLu
