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

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

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.



... registered to home network in 3G


... however SMONI says we are only camping

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

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


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

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

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


... 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



... we redundantly enable registration URC


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


... 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??