quectel-support

• Conf file:

/opt/support/QLog_Linux_and_Android_V1.5.26/conf/default_adpl_1e1e.cfg

• Qlog command:

/opt/support/QLog_Linux_and_Android_V1.5.26/out/QLog -s /opt/support/logs &>/opt/support/Qlog.out

• AT Commands issued using at the minicom -D /de v/ttyUSB3 terminal:

AT+QGMR
RM520NGLAAR01A08M4G_01.204.01.204

OK
AT+CSUB
SubEdition: V01

OK
AT+CFUN=0
OK

+CFUN: 0

AT+CFUN=1
+CME ERROR: 0

at+qcfg="aprstlevel",0
OK
at+qcfg="modemrstlevel",0
OK
at+qcfg="dbgctl",0
OK
at+qtest="dump",1
RDY

+QUSIM: 1

+QIND: SMS DONE
AT
OK

+QIND: PB DONE
AT
OK
AT
OK
AT
OK

OK
ATE
OK

quecte support thread about the same issue:

https://forums.quectel.com/t/rm521f-and-rm520n-cannot-register-to-the-network/34831/6