Problems with cellular connectivity

[tonybolton]

I’m regularly seeing the following behaviour with my imp006c modules in development.
I think this is due to our very poor cellular coverage. Can anyone explain what’s going on here, i.e. what timeouts might be affecting the update process etc.
Thanks,
Tony

|2023-02-10T15:55:18.810 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|---|---|---|
|2023-02-10T15:55:18.867 +00:00|[Status]|Device disconnected|
|2023-02-10T15:58:34.696 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-10T15:58:34.793 +00:00|[Status]|Device disconnected|
|2023-02-10T16:01:30.529 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-10T16:01:30.626 +00:00|[Status]|Device disconnected|
|2023-02-10T16:03:16.214 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-10T16:03:16.309 +00:00|[Status]|Device disconnected|
|2023-02-10T16:05:49.411 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-10T16:05:49.507 +00:00|[Status]|Device disconnected|
|2023-02-10T16:06:52.145 +00:00|[Status]|Device disconnected|
|2023-02-10T16:07:59.174 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-10T16:11:32.176 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-10T16:11:32.271 +00:00|[Status]|Device disconnected|
|2023-02-10T16:13:17.011 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-10T16:13:17.048 +00:00|[Status]|Device disconnected|
|2023-02-10T16:16:03.376 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-10T16:16:03.471 +00:00|[Status]|Device disconnected|
|2023-02-10T16:18:26.847 +00:00|[Status]|Device disconnected|
|2023-02-10T16:19:32.019 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-10T16:22:46.731 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-10T16:22:46.811 +00:00|[Status]|Device disconnected|
|2023-02-10T16:26:28.153 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-10T16:26:28.249 +00:00|[Status]|Device disconnected|
|2023-02-10T16:29:33.950 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-10T16:29:34.046 +00:00|[Status]|Device disconnected|
|2023-02-10T16:32:11.066 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-10T16:32:11.161 +00:00|[Status]|Device disconnected|
|2023-02-10T16:34:14.874 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-10T16:34:14.968 +00:00|[Status]|Device disconnected|
|2023-02-10T17:34:50.870 +00:00|[Status]|Device disconnected|
|2023-02-13T08:51:34.251 +00:00|[Status]|Downloading new code; 28.36% program storage used|
|2023-02-13T08:51:57.448 +00:00|[Device]|[INFO] Application COMMS 1.0 build DEV-619|
|2023-02-13T08:51:57.508 +00:00|[Device]|[DEBUG] Wake reason: Powered on (cold boot)|

[cvrdrvn]

I’ve had issues like this. I suggest that you prepare a lightweight piece of squirrel that it substantially smaller than the 28% it currently is. The smaller it is, the more likely it is to transfer in its entirety. If possible, include code that will tell you what is going on with the connection (eg ::imp.net.getcellinfo(callback)).
I found that some of the most problematic connections came when the imp006 fell back to GPRS. Electric Imp has a library you can include in your code that will allow you to disable GPRS, forcing the modem to find an LTE-M connection.
Another option might be to play with the Twilio SuperSIM settings to omit one of the LTE providers, if there is more than one.
I should note that you need to be careful with blocking networks or radio options, as you could end up with no connection at all.

[tonybolton]

Thanks for the feedback, very useful.
Unfortunately our office is in an LTE-M dead-zone and on the edge of a 2G wilderness.
Tony