[BC92] - NB-IoT Connection Process

Technical Subjects
1

I am developing a solution using the BC92 module.

I am facing a situation where the device takes too long to detect and connect to the network (5-30min).
Here are the commands I am using to connect the device.

AT+CPIN?

+CPIN: READY

OK


+CPIN: READY
AT+QBAND?
+QBAND: 3,5,8,20,28

OK

AT+QCSEARFCN=0
OK

AT+QSCLK=0
OK

AT+CPSMS=0
OK

AT+CPSMS?
+CPSMS: 0

OK

AT+CFUN=0

OK

AT+QCGDEFCONT=1
ERROR

AT+QCGDEFCONT?
+QCGDEFCONT: "IP","nbiot.gsim","tim","tim",1

OK

AT+CGREG=2
OK

AT+CMEE=2
OK

AT+QNWCFG?
+QNWCFG: 1

OK

AT+CGATT?
+CGATT: 0

OK

AT+CFUN=1,1
OK


RDY

+CFUN: 1


+CPIN: READY

AT+QSCLK=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+COPS?
+COPS: 0

OK

AT+CSQ
+CSQ: 99,99

OK

Do you recommend something different?

2

Are you currently commissioning and testing in Brazil? Or are you sure of the current frequency band of the NB radio network？

3

Hi @herbert.pan-Q

Yes, I am in Brazil.
I think the operating band here is B28 (700MHz).

4

you can run:

AT+CFUN=0
AT+QBAND=1,28
AT+QCSEARFCN=0
AT+CSCON=1
AT+CFUN=1
AT+CEREG? //The query is performed 2min at an interval of about 2s
AT+QENG=0 //The query is performed 2min at an interval of about 2s

then provide your log

5

Here is the log.

+CPIN: READY

AT+CFUN=0

OK

AT+QCSEARFCN=0
OK

AT+QBAND=1,28
OK

AT+QENG=0
OK

AT+QCGDEFCONT?
+QCGDEFCONT: "IP","nbiot.gsim","tim","tim",1

OK

AT+CGREG=2
OK

AT+CMEE=2
OK

AT+QNWCFG?
+QNWCFG: 1

OK

AT+CGATT?
+CGATT: 0

OK

AT+CFUN=1,1
OK


RDY

+CFUN: 1

AT+QSCLK=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,0

OK


+CPIN: READY
AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 99,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CSQ
+CSQ: 31,99

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
+QENG: 0,9556,,47,"0",-64.00,27,-49,-1,28,"0",0,0

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+CEREG?
+CEREG: 0,2

OK
6

It is recommended to run the order of the above commands, and the preliminary judgment is caused by network rejection (SIM card exception).

7

Hi,

I think the service provider is refusing the connection.

+CPIN: READY

OK


+CPIN: READY

AT+CFUN=0

OK

AT+QBAND=1,28
OK

AT+QCSEARFCN=0
OK

AT+CSCON=1
OK

AT+CFUN=1,0
OK

AT+QCGDEFCONT="IP","nbiot.gsim","tim","tim",1
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
+QENG: 0,9556,,47,"0",-61.00,33,-47,-1,28,"0",0,0

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
+QENG: 0,9456,,231,"0",-77.03,25,-64,1,28,"0",0,0

OK


+CSCON: 1

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
+QENG: 0,9456,,231,"0",-77.11,24,-64,1,28,"0",0,5

OK

AT+CEREG?
+CEREG: 0,2

OK

AT+QENG=0
+QENG: 0,9456,,231,"0",-76.11,26,-64,3,28,"0",0,-5

OK


+CSCON: 0

AT+CEREG?
+CEREG: 0,3

OK

AT+QENG=0
+QENG: 0,9456,,231,"35add2b",-75.44,27,-62,3,28,"aa4c",0,-5

OK

AT+CEREG?
+CEREG: 0,3

OK

AT+QENG=0
+QENG: 0,9456,,231,"35add2b",-75.78,27,-63,6,28,"aa4c",0,-5

OK

AT+CEREG?
+CEREG: 0,3

OK

AT+QENG=0
+QENG: 0,9456,,231,"35add2b",-76.04,26,-63,6,28,"aa4c",0,-5

OK

AT+CEREG?
+CEREG: 0,3

OK

AT+QENG=0
+QENG: 0,9456,,231,"35add2b",-76.25,26,-63,5,28,"aa4c",0,-5

OK

AT+CEREG?
+CEREG: 0,3

OK

AT+QENG=0
+QENG: 0,9456,,231,"35add2b",-76.48,26,-63,3,28,"aa4c",0,-5

OK
8

Oh, it is probably caused by the mismatch of the APN of the SIM card, please contact Tim to solve it