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)?
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?
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.
We got the following information from our provider:
The SIM card have the following spec:
Cardbody Size: 85.7 (+/- 0.125mm) x 54mm (+/- 0.05mm), according to ISO 7816 Operating- & Storage temperature: -40°C to + 105°C (-40°F to 221 °F) Supply Voltage: SO class A (5V), B (3V) & C (1.8V)
The cards only use ISIM. According to our provider this is kind of the default in Europe.
Like I told you, I went to the modem. When I got there last Tuesday, the complete modem was reset. Non of our applications were running and all configuration were files deleted. Once I set up the modem again, everything was running smoothly. This is quite strange, because a coworker was inspecting the modem on the 25th of November when the software was still running and cm sim status returned LE_SIM_STATE_UNKNOWN. The modem is at a very remote place and locked inside a box, there was no vandalism or anything like that.
Hi Michael,
Regarding the SIM_STATE_UNKNOWN, I’ve checked internally and there are no other reports of this issue. Is it possible that inside the locked box, the humidity conditions are exceeded?
Regarding the loss of applications:
Is there constant power to the device, or is power removed? If power is removed, how frequent? There is a known issue in Legato 16.10 in which constant power cycling can cause corruption on the device resulting in a factory reset.
I’ve seen other reports on the Legato forum of customers losing their applications. It’s possible that the Legato rollback kicked in when it wasn’t supposed to
If the radio module itself detected corruption, there is an internal EFS recovery mode
It’s very difficult to determine which one of these have occurred. We’re targeting to release R17 towards the end of January. Is it possible to upgrade your devices with the new version once available?