Anyone with IoT SIM Cards and cellular connectivity experience? Need help where to look for problems
Hey all. I work in the IoT industry and our devices using KORE Super SIM cards to connect to the internet via cellular. KORE had an outage on Thursday, and only 2/3rds of our devices connected. FYI KORE Super SIM was previously Twilio Super SIM. KORE purchased that business unit in 2023 and they are still migrating.
I only have experience working with the higher-level APIs available in KORE/Twilio. Stuff like activating SIMs, resetting connectivity, etc. I don't really understand the low level stuff about SIMs authorizing with a tower and such.
I'm not asking for help troubleshooting that's a huge ask. But if there's anyone here that can give me a crash course on this I'd appreciate it. I at least want to be more educated and at least have a starting point for where to find a solution. I've gone 18 hours with no response from the support case with have with KORE, so kind of desperate lol.
7 Replies
Are you seeing any errors or can you share any logs?
Yeah there are SIM logs for the sim attaching and establishing a data session. The problem is there aren’t really errors. Just weird behavior.
Data session starts, then lasts a minute or two, then ends. Then resetting the SIM or power cycling the device doesn’t fix anything. That behavior happens even if the SIM is replaced.
We’re starting think it’s something with the devices firmware for the modem at this point which would suck.
have you tried SIMs from a different provider in the devices?
We unfortunately don’t have any SIMs immediately available to try. What we did try was updating the network access profile to restrict the carriers it could connect to in case it was a specific carriers. Before it would find the best connection between Verizon, T-Mobile, etc. But that didn’t seem to help either.
Since it’s only since the downtime your having the issue I’d really try to get a third party SIM to rule this out before assuming it’s firmware etc
Good idea. I’ll see what other SIMs we have around tomorrow. Appreciate the help!
Hey so haven't been able to try out a different SIM yet.
We were able to pull logs from the device. The device is saying that it fails to activate the model.
There are also logs indicating it rapidly tried to connect to a tower. Do towers have systems in place to block SIM cards if they indicate behavior similar to that? Almost like a rate limit or firewall?
The specific log from the device is
Mon, 20 Jan 2025 15:54:15.373 [lte] : <debug> AT+CEREG?: tries=1, response=+CEREG: 0,0
Here's a few more logs if you can glean anything from them.
Mon, 20 Jan 2025 13:14:17.038 [lte] : <info> LTE Modem Activate result: FAILURE, reason=25
Mon, 20 Jan 2025 13:19:22.382 [lte] : <error> LTE /dev/ttyACM0 could not open.
can you try one of your personal phone SIMs in the device to see if it will connect?