I have an issue that seems to be plaguing some of my units, where occasionally they will no longer be able to detect their sim card and was looking to see if anyone would be able to troubleshoot the issue:
Normal operation for these devices is to wake up every 15 minutes to send data to the cloud through cellular and to go into lite hibernate in between. Now when the device wakes up, +KSUP: 0 is expected before sending commands signaling that the device is ready. The error will then occur afterwards where the modem will occasionally send in +KSUP:2 immediately afterwards which signifies that it can’t read the sim card.
Once this message is sent, it won’t be able to read the sim card until a reboot is issued at which point it will try, most likely succeed, and then fail a few hours later in the same pattern. At first I thought that this was a single unit with potentially a bad solder joint but now I am seeing more units with this behavior.
This leads me to my two questions:
- What can I do to recover from +KSUP: 2, is there a way to enforce reading the sim card again?
- What causes a +KSUP: 2? If I’m aware of the exact criteria that causes the HL7800 to respond with the messages I can try and figure out where the device is going awry.
Also if anyone has seen this behavior and has some input, I would be happy to try and troubleshoot it with them.