Quectel BG77 unable to register automatically to a NB network

IoT Modules LPWA Module
1

Hi! I’m using a Quectel BG77 with a NB-IoT SIM.

I’m trying to register on the network automatically, but I can’t.

My network configuration is as follows:

D (13300) quectel: Sending data
D (13800) quectel: Received: AT+CFUN?
+CFUN: 1

OK

D (13800) quectel: Sending data
D (13830) quectel: Received: AT+QCFG=“servicedomain”
+QCFG: “servicedomain”,2

OK

D (13830) quectel: Sending data
D (13860) quectel: Received: AT+QCFG=“NWSCANSEQ”
+QCFG: “nwscanseq”,030201

OK

D (13860) quectel: Sending data
D (13890) quectel: Received: AT+QCFG=“band”
+QCFG: “band”,0x0,0x100002000000000f0e189f,0x80004

OK

D (13890) quectel: Sending data
D (13920) quectel: Received: AT+QCFG=“IOTOPMODE”
+QCFG: “iotopmode”,1

OK

D (13920) quectel: Sending data
D (13960) quectel: Received: AT+COPS=0
OK

D (13960) quectel: Sending data
D (13990) quectel: Received: AT+COPS?
+COPS: 0

OK

D (13990) quectel: Sending data
D (117800) quectel: Received: AT+COPS=?
+COPS: (1,“Movistar”,“Movistar”,“21407”,9),(1,“vodafone ES”,“voda ES”,“21401”,9),(1,“Orange SP”,“ESPRT”,“21403”,9),(0,1,2,3,4),(0,1,2)

OK

D (117800) quectel: Sending data
D (117840) quectel: Received: AT+CSQ
+CSQ: 99,99

OK

D (117840) quectel: Sending data
D (117870) quectel: Received: AT+QCSQ
+QCSQ: “NOSERVICE”

OK

D (117870) quectel: Sending data
D (117890) quectel: Received: AT+CEREG?
+CEREG: 0,2

OK

D (119390) quectel: Sending data
D (119410) quectel: Received: AT+CEREG?
+CEREG: 0,2

OK

At this point, I never receive a +CEREG: 0,5

As you can see from the QCFG configuration, everything is set up to operate with NB networks, and it detects the networks (AT+COPS=?), but the module isn’t attaching to any of them.
Am I doing something wrong?

Thanks,

2

Hi @Gerard_Massana

Can you try to fix band to test? the first time of registering to NB network will be take a bit long time, because there is no RPLMN and histrocial freqs, and the NB bandwidth shorter than Cat-M1.

3

Hi @Linkin-Q

Yes, I’ve attempted to manually fix the band, and it worked. However, upon restarting the module and configuring cops automatically, it consistently takes between 2-3 minutes to automatically register on the NB network, and sometimes fails to do so. Is this behavior normal? We opted for the BG77 specifically for its NB and CATM1 capabilities, but if it consistently takes a minimum of 2 minutes to auto-register…
Is there anything else we should be doing?

REGISTERING MANUALLY
at+cops=?
+cops: (1,“Orange SP”,“ESPRT”,“21403”,9),(1,“Movistar”,“Movistar”,“21407”,9),(1,“vodafone ES”,“voda ES”,“21401”,9),(0,1,2,3,4),(0,1,2)
OK

at+cops=1,0,“Movistar”,9
+CME ERROR: 30

at+cops=1,0,“Orange”,9
+CME ERROR: 30

at+cops=1,2,“21403”,9
OK

at+cops?
+cops: 1,2,“21403”,9
OK

at+cereg?
+CEREG: 0,5
OK

RESTART MODULE, AND TRYING TO REGISTER AUTOMATICALLY
RDY
APP RDY

at+cereg?
+CEREG: 0,0
OK

at+cfun?
+CFUN: 1
OK

at+cops=0
OK

at+cops?
+COPS: 0
OK

at+cereg?
+CEREG: 0,2
OK

at+cereg?
+CEREG: 0,2
OK

at+cereg?
+CEREG: 0,2
OK

at+cereg?
+CEREG: 0,2
OK

at+cops?
+COPS: 0
OK

at+cereg?
+CEREG: 0,2
OK

at+cereg?
+CEREG: 0,3
OK

at+cereg?
+CEREG: 0,3
OK

at+cops?
+COPS: 0
OK

at+cops?
+COPS: 0
OK

at+cereg?
+CEREG: 0,3
OK

at+cereg?
+CEREG: 0,5
OK

at+cops?
+cops: 0,0,“Orange SP”,9
OK

4

HI @Gerard_Massana

Seems you are using roaming service right?
Please try to disable HPLMN search, AT+QNWCFG=“hplmnsearch_ctrl”,0 reboot to take effect.
As you can see log +CEREG:0,3 which means reject by network, also you can get reject cause by AT+QCFG=“emmcause” command.