Asset_tracker startup network

[rarhodes@indesign]

I'm using the asset_tracker app on a custom board and have built 50 of the custom boards. All but one of them start the modem and listen to the LTE receiver for a full minute before choosing a carrier to connect to. One of the boards connects to the same network it was last connected to a few seconds after startup. I've tried lots of combinations of AT commands to try to get the modems to "remember" the last connected network, but short of forcing a connection with an AT+COPS=1,2,"xxxxxxx" command I haven't been able to get the rest of them to connect in under a minute. Does anyone know how to evoke this behavior? We are not sure what we did to make the single unit that connects directly at startup behave this way.

[Carl Richard]

Hello, Rarhodes!

Thanks for reaching out. Shutting down the modem using AT+CFUN=0 after a connection have been made should store information about the last connected network. Did you try this?

If that doesn't help please provide some modem traces. One from the fast connecting device and one from a slow connecting device.

Best regards,
Carl Richard

[rarhodes@indesign]

Thank you Carl. I had tried this in the past with no luck, but I just tried it again and it seems to have worked fine. So thank you for that. A related question. I have built 50 prototype units here in the lab which are to be deployed in a field trial soon. These will be brought up in remote locations with no way to issue an AT+CFUN=0 command to them manually. Is there a way to force the asset_tracker application to do this without intervention?

[Carl Richard]

HI again!

Good to hear that it seems to work. The modem configuration (including network data) is stored automatically every 48 hours, as stated in the AT Reference Manual (not in the most obvious location, unfortunately). If you want to save it right away you must call AT+CFUN=0 from within the asset_tracker application after the connection is established, and then reconnect. It should be enough to disconnect after the modem_configure function in main is finished before reconnecting again.

Best regards,
Carl Richard