At+qcfg="nwscanmode" and at+qcfg="nwscanmodeex" changes after cops=2 and cops=0

Technical Subjects
1

Please see at command log below and why at+cops=2 and at+cops=0 reset the at+qcfg=“nwscanmode” and at+qcfg=“nwscanmodeex” settings ???

at+qcfg=“nwscanmode”

+QCFG: “nwscanmode”,3

OK

at+qcfg=“nwscanmodeex”

+QCFG: “nwscanmodeex”,16

at+qcfg=“nwscanmode”

+QCFG: “nwscanmode”,3

OK

at+qcfg=“nwscanmodeex”

+QCFG: “nwscanmodeex”,16

OK

at+cops=2

OK

at+cops=0

OK

+QIND: SMS DONE

at+qcfg=“nwscanmode”

+QCFG: “nwscanmode”,0

OK

at+qcfg=“nwscanmodeex”

+QCFG: “nwscanmodeex”,63

OK

at+qgmr

EG25GGBR07A08M2G_30.004.30.004

OK

2

I believe this is a Qualcomm idiosyncrasy. Many brands of modem other than Quectel, which use Qualcomm chipsets, also exhibit the same behaviour.

The work around is to include the RAT in the +COPS command. So use AT+COPS=0,,,7 instead of AT+COPS=0

3

we use Telit modules that are based on same Qualcomm chipset and they don’t have this issues. AT+COPS=0 does not auto reset the RAT settings

AT+COPS=0,7 does not work and it auto reset all the settings in these commands
AT+QCFG=“nwscanmode”,
AT+QCFG=“nwscanmodeex”
AT+WS46

4

That’s not the command I gave you.

5

mistyped. we did tried

AT+COPS=0,,,7

why AT+COPS=0 auto reset all the settings for the other AT commands ?

6

I think someone a very long time ago has misinterpreted 3GPP 27.007 section 7.3.

I first came up against this problem with Sierra Wireless modems more that a decade ago.

The +COPS command is supposed to be about PLMN (network) selection, with RAT (access technology) selection tagged on as an optional extra.

I believe that setting the RAT to automatic whenever the PLMN is set to automatic is a mistake, and maybe even a bug.

If you want to deregister and then reregister with the network, consider using AT+CFUN=4 followed by AT+CFUN=1 instead of +COPS.