Forcing 3g Connection on MSOM 524

Firmware
1

I have devices that jump between LTE and 3g. 3g is getting strong signal strength, but LTE is very low (15-20%) and 3g is strong (~80%).

I want to try locking the modem to 3g. Is that possible?

Thanks!

2

There isn't an automatic way to do this. There are two possible ways that I can think of:

With Device OS 6.4.0 and later, you can use Environment PARTICLE_CELLULAR_FORBIDDEN_BANDS you should be able to disable all of the bands, which really only specifies the LTE bands. The default setting should still be used for 2G/3G. I have not tested this, so I'm not positive it will work, but I think that's how it's supposed to work.

With the EG91-EX cellular modem (M524), you can use the AT+QCFG="nwscanseq" command to search 3G then 2G only (030201) instead of automatic (00). The cellular modem needs to be restarted after changing this setting, which I think is sticky.

3

Thanks @rickkas7 , I will give that a try.

4

Make sure you are using the correct antenna for the M524. That level of LTE performance is not expected.

5

Thank you for the suggestions @rickkas7 .

We tested applying forbidden bands on an M404 device locally after having updated to OS6.4.0, and we were unable to restrict the device to 2G/3G. With all bands forbidden, we are still seeing LTE connection.

Further, we tried the M524 (EG91-EX cellular modem) workaround, but still saw the device connecting to LTE services. Is it expected that the "search 3G and then 2G only" option would fall back to no connection, if no suitable 2G/3G network was found?