BC35-G and AT+CSQ=99,99

IoT Modules
1

Hi there,
I’m using an BC35-G with a multi carrier m2m sim by 1nce. If I keep the module powered off for a while (approximately 1 week), when I start up it again, it takes a lot of time to be registered to the network (around 5-10 minutes).

This is the list of command and the response of the module:

[12:02:48.531] ATI
[12:02:48.562] Quectel
[12:02:48.571] BC35-G
[12:02:48.581] Revision:BC35GJCR02A01

[12:03:42.687] ATE1
[12:03:42.708] OK

[12:03:55.144] AT+CSQ
[12:03:55.185] +CSQ:99,99

[12:03:56.134] AT+CSQ
[12:03:56.184] +CSQ:99,99

[12:03:57.154] AT+CSQ
[12:03:57.184] +CSQ:99,99

[12:03:58.124] AT+CSQ
[12:03:58.184] +CSQ:99,99

[12:03:59.144] AT+CSQ
[12:03:59.184] +CSQ:99,99

...

[12:09:01.144] AT+CSQ
[12:09:01.180] +CSQ:29,99

On the other hand, if i use it more frequently, it connects everytime in a bunch of seconds. Am I supposed to do something particular? Is there something I can do to speed up the connection process even when the module is been powered on after a while?

Thank you in advance.

2

Please execute the following commands in order

AT+CFUN=0
AT+NCSEARFCN
AT+CSCON=1
AT+CFUN=1
AT+CGATT=1
AT+CIMI
AT+NBAND?
AT+CGDCONT?
AT+CEREG?
AT+CEREG?
AT+CEREG?
AT+CGPADDR

3

This is the output:

[16:09:28.290] AT+CFUN=0
[16:09:28.321] OK
[16:09:28.341] 
[16:09:35.230] AT+NCSEARFCN
[16:09:35.252] OK
[16:09:45.095] 
[16:09:54.004] AT+CSCON=1
[16:09:54.025] OK
[16:09:54.047] 
[16:10:35.804] AT+CFUN=1
[16:10:35.836] OK
[16:10:35.845]
[16:10:42.031] AT+CGATT=1
[16:10:42.052] OK
[16:10:42.081] 
[16:10:48.410] AT+CIMI
[16:10:48.432] 901405102770102
[16:10:48.471] 
[16:10:48.471] OK
[16:10:48.474] 
[16:10:54.064] AT+NBAND?
[16:10:54.085] +NBAND:20,8,3,1
[16:10:54.124] 
[16:10:54.125] OK
[16:10:54.125] 
[16:10:59.829] AT+CGDCONT?
[16:10:59.859] +CGDCONT:0,"IPV4V6",,,0,0,,,,,0,0
[16:10:59.919] 
[16:10:59.919] OK
[16:10:59.919] 
[16:11:14.128] AT+CEREG?
[16:11:14.160] +CEREG:0,2
[16:11:14.190] 
[16:11:14.190] OK
[16:11:14.194] 
[16:11:17.069] AT+CEREG?
[16:11:17.100] +CEREG:0,2
[16:11:17.131] 
[16:11:17.131] OK
[16:11:17.136] 
[16:11:20.032] AT+CEREG?
[16:11:20.062] +CEREG:0,2
[16:11:20.092] 
[16:11:20.092] OK
[16:11:20.097] 
[16:11:24.346] AT+CGPADDR
[16:11:24.367] +CGPADDR:0
[16:11:24.397] OK
[16:11:24.402]

Thank you

4

I’m trying also with other SIM by different provider but it stays indefinitely in “+CEREG:0,2” status and it connects to the network after a lot of time. Any suggestion? Thank you

5

According to your serial port log analysis, it may be caused by weak signal. If possible, I suggest you grab the debug log
Quectel_UEMonitor操作指导与参考(CN&EN).pdf (1.6 MB)

6

I’ve no access to the debug pins since the module is embedded in a devboard. However, after the first connection it works for a while keeping the board in the same spot and not moving it at all. Since that I don’t think it is a coverage issue. Moreover when it connects the CSQ replies in 28-30 range, so it is not bad.
Can you please send me the minimum command list to connect to a mqtt server and test the connection?
This is what I do:

ATI

Quectel
BC35-G
Revision:BC35GJCR02A01

OK


AT+NCSEARFCN

OK

AT+NBAND=1,3,5,8,20,28

OK


AT+CSCON=1

OK

AT+CFUN=1

OK


AT+CGDCONT=0,"IPV4V6","iot.1nce.net"

OK


AT+CIMI

901405103105677

OK

AT+CGATT=1

OK

AT+CGDCONT?
+CGDCONT:0,"IPV4V6","iot.1nce.net",,0,0,,,,,0,0

OK

AT+CEREG?
+CEREG:0,2

OK

AT+CEREG?
+CEREG:0,2

OK

AT+CEREG?
+CEREG:0,2

OK

AT+CSQ
+CSQ:99,99

OK

AT+CSQ
+CSQ:99,99

OK

AT+CSQ
+CSQ:99,99

OK

Am I missing something?

7

I can’t judge by your UART Log. I suggest you grab the DEBUG port Log