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PLS8-E permanently switches between 3G and 4G | Telit Cinterion IoT Developer Community

March 3, 2021 - 6:38pm, 1379 views

Hi.
We have a PLS8-E here, that in the current configuration we want to run in
- automatic network selection
- without establishing a data connection (short messaging only).

Hard to reproduce, but repeatedly, it enters a state where it keeps registering and unregistering between 3G and 4G indefinitely, without ever reaching a stable connection. After a power cycle, or even a simple band reselection, this state is gone.

When this happens, different commands/URCs seem to have "different ideas" of what the actual registration status is.

I will post such an annoted sequence below, all of which happens repeatedly, indefinitely, within about 25 seconds.

I will make a follow up post with some additional configuration info.

Has anybody ever encountered this? Any ideas what is going on?
Thanks in advance.

----------------------------------------------------------------------------------

> AT+CREG?

... registered to home network in 3G

> AT^SMONI

... however SMONI says we are only camping

... URC: WCDMA PS attached (3G packet domain)

... URC: we are HSDPA PS attached ("3.5G" packet domain)

> AT^SMONI

... SMONI says again we are camping on 3G

... URC: we are E-UTRAN attached now (4G)

... URC: registered to home network in 4G

> AT+CGACT?
> AT+CGDCONT?

... we query CGACT and CGDCONT (redundantly, since we do not plan to set up a data connection in this configuration)

> AT+COPS=3,0;+COPS?;+COPS=3,1;+COPS?;+COPS=3,2;+COPS?

... we query the IDs of the current operator

rild: RIL processRequest() VOICE_REGISTRATION_STATE

> AT+CREG=2

... we redundantly enable registration URC

> AT+CREG?

.... we query CREG, and it now says we are registered to our home network in 3G

> AT^SMONI

... but SMONI says we do not even have a 3G network

... URCs inform us we are searching for an operator

... time

... URC: no service

... URC: camoed on E-UTRAN (4G)

... URC: no operator

... URC: GPRS not available??