BC66: Registration denied

ishuan · March 26, 2021, 3:10pm

Hi all,

I just received BC66-TE-B development board. The problem is I can not register to the operator.

After connecting to the computer, I reset the device with RESET button and after initial message from MODEM:

F1: 0000 0000
V0: 0000 0000 [0001]
00: 0006 000C
01: 0000 0000
U0: 0000 0001 [0000]
T0: 0000 00B4
Leaving the BROM

I follow these steps:

Turn off Power Saving Mode

AT+QSCLK=0
> OK

Turn off Echo Mode

AT0
> OK

Is PIN Code Required?

AT+CPIN?
> +CPIN: SIM PIN

Enter Pin

AT+CPIN="1234"
> OK

Stop Connecting

AT+CGATT=0
> OK

Get List of Available Operators

AT+COPS=?
> +COPS: (1,"23002","23002","23002",9),(1,"23003","23003","23003",9),(1,"23001","23001","23001",9),,(0-4),(0-2)

Select My Operator

AT+CFUN=0
> OK
AT+COPS=1,2,"23002"
> OK
AT+CGDCONT=1,"IP","internet"
> OK
AT+QCGDEFCONT="IP","internet"
> OK
AT+CFUN=1
> OK
> +CPIN: SIM PIN
AT+CPIN="1234"
> OK

Restart Modem

AT+QRST=1
> OK

Disable Power Saving Mode

AT+QSCLK=0
> OK

Disable Echo

ATE0
> OK

Enable Event Reporting

AT+QNBIOTEVENT=1,1
> OK

Check Signal Strength

AT+CSQ
> +CSQ: 99,99

That is weird, but maybe because we are not connected yet?

Enable Event Reporting

AT+CEREG=5
> OK

Connect

AT+CGATT?
> +CGATT: 0

Still off, turn it on… For some reason, turning it on with:

AT+CGATT=1
> ERROR

did not work. So I had to AT+CFUN=0 and AT+CFUN=1 again to start connecting.

Then this appeared:

+CEREG: 2,,,,,0,0
+CEREG: 3,,,,,0,15
+CEREG: 0,,,,,0,0
+CEREG: 2,,,,,0,0
+CEREG: 0,,,,,0,0
+CEREG: 2,,,,,0,0
+CEREG: 0,,,,,0,0
+CEREG: 2,,,,,0,0

Checking registration status returns:

AT+CGATT?
> +CGATT: 0

So we are still not connected. What is the status?

AT+CEREG?
> +CEREG: 5,0,,,,,0,0

Sometimes, this ends with +CEREG: 5,0, sometimes +CEREG:5,3…

Extended signal info still returns that there is no signal.

AT+CESQ
> +CESQ: 0,0,255,255,0,0

I don’t know, what I am doing wrong. Maybe I just set something wrong during my previous attempts and connection is failing because of that.

Or maybe my steps are not in right order, but I tried to follow application design workflow, as described in: Application Manual

Is there a chance, that my SIM card does not support this type of connection? To be honest, I still don’t know if I am using LTE or NB-IOT. Only thing which may be selecting between these two is AT+QBAND command, which is set to:

AT+QBAND?
> +QBAND: 20

Which should be supported: O2 Czech Republic

Because support from the operator is non-existing, I don’t know wheter is my fault, or something connected to SIM card setup on operator’s side.

Thank you in advance for any tips.

herbert.pan-Q · March 29, 2021, 9:51am

Hi Ishuan:

When you check the operators supported by your module through AT commands,

AT+QBAND?
+QBAND: 20
The result explain that the local support NB-IOT, and the network frequency band number is 20;

AT the same time,the result you get the result through the AT command

AT+COPS=?
+COPS: (1,“23002”,“23002”,“23002”,9),(1,“23003”,“23003”,“23003”,9),(1,“23001”,“23001”,“23001”,9),(0-4),(0-2)
The 9 also shows that your area supports E-UTRAN (NB-S1 mode)，You can also view the corresponding result parameters through the AT command manual of the BC66 module.

We have also reproduced your operation through the same method, and the results we performed are different from yours.

[2021-03-29_16:30:52:342]at+cpin?
[2021-03-29_16:30:52:342]+CPIN: READY

Our SIM card does not need to enter a PIN according the above results。

If your SIM must be verified by a PIN code, it is important that the PIN code is entered correctly. So, you need to reconfirm whether the PIN you entered is wrong.

You want to access the network through APN during your previous operation, therefore, APN also requires you to confirm repeatedly, APN should be consistent with what the SIM provider provides.

We suggest that you turn on the echo command before you operate the AT command, And there is a certain interval between operation commands.

According to the above suggestions, if there are still problems, I suggest you save the operation log and upload it, and communicate with us in time, thank you！

ishuan · March 30, 2021, 11:11am

Hi Herbert, thank you for you response.

AT+QBAND?
+QBAND: 20

This is set to band 20 just because I set it to this specific value. It is not something that was ‘detected’ by the module.
Basically I used one of values listed on O2 Czech Republic – M2M as supported by this carrier. It should be valid, since when I insert this SIM card into my phone, Band 20 is selected automatically.
When I left default value of QBAND (1, 2, 3, 4, 5, 8, 12, 13, 17, 18, 19, 20, 25, 26, 28, 66) search for available operators via COPS took forever. So I limited it to one band to speed search up.

The 9 also shows that your area supports E-UTRAN (NB-S1 mode)，You can also view the corresponding result parameters through the AT command manual of the BC66 module.

What does this mean for setup process? Should I change something accordingly? I am new to this and internet sources about NB-S1 are sparse.

We have also reproduced your operation through the same method, and the results we performed are different from yours.

My SIM card requires the PIN. So I disabled it with AT+CLCK="SC",0,"1234".

I tried using QNavigator from your website. But still no luck. Log is attached.

log130600.zip (2.0 KB)

It is brand new BC66-TE-B board, so except default PDP context, everything is set to default.

I still cannot connect to carrier.

ishuan · March 30, 2021, 12:13pm

I tried following this tutorial, did everything as they said. However, I end up with registration denied again.

List of commands used.

Communication log

Since using the same SIM card, my phone has no problem connecting to internet, I have following questions:

May it be, that phone uses LTE, but BC66 uses NB-IOT network? In that case, is it possible, that the SIM card is not NB-IOT enabled?
Is there something I skipped when setting up the connection? APN is correct (the same APN is shown on phone), so is BAND and COPS (which I did not set this time).
I found this link. According to it, BC66 supports only LTE CAT-M1 and LTE NB-IOT. Is it possible, that my SIM card is “generic” data SIM card without support of those two LTE types? So it works in phone (which uses standard LTE), but not in BC66…

Other than that, could you recommend me what to do next?

ishuan · March 31, 2021, 3:17pm

So I contacted my carrier again. According to them, SIM card is enable for LTE CAT-M1. They did not specify LTE NB-IOT.

They did confirm that APN and COPS values are valid.

Still no luck. Most of the time, I end up with

+CEREG: 3,,,,,0,13

or

+CEREG: 3,,,,,0,15

This is communication log:

F1: 0000 0000
V0: 0000 0000 [0001]
00: 0006 000C
01: 0000 0000
U0: 0000 0001 [0000]
T0: 0000 00B4
Leaving the BROM

RDY
+CFUN: 1

+CPIN: READY
AT+QSCLK=0
AT+QSCLK=0

OK
AT+COPS?
AT+COPS?

+COPS: 0

OK
AT+QBAND?
AT+QBAND?

+QBAND: 20

OK
AT+CGSN=0
AT+CGSN=0

MPA20IO160014841P

OK
AT+CGSN=1
AT+CGSN=1

+CGSN: 867997031707952

OK
AT+CIMI
AT+CIMI

230020101473750

OK
AT+CEREG=5
AT+CEREG=5

OK
AT+CSCON=1
AT+CSCON=1

OK
AT+QNBIOTEVENT=1,1
AT+QNBIOTEVENT=1,1

OK
AT+QCGDEFCONT="IP","internet"
AT+QCGDEFCONT="IP","internet"

OK
AT+CESQ
AT+CESQ

+CESQ: 0,0,255,255,0,0

OK
AT+CEREG?
AT+CEREG?

+CEREG: 5,3,,,,,0,15

OK
AT+CFUN=0
AT+CFUN=0

+CEREG: 0,,,,,0,0

OK
AT+QCSEARFCN
AT+QCSEARFCN

+QCSEARFCN: 0

OK
AT+CFUN=1
AT+CFUN=1

OK

+CPIN: READY

+CEREG: 2,,,,,0,0

+CSCON: 1

+CEREG: 3,,,,,0,15

+CSCON: 0
AT+CSQ
AT+CSQ

+CSQ: 0,0

OK
AT+CESQ
AT+CESQ

+CESQ: 0,0,255,255,0,0

OK

+CSCON: 1

+CSCON: 0

+CSCON: 1

+CSCON: 0

+CEREG: 3,,,,,0,13

For some reason, signal strength is still 0 (AT+CSQ). I did not find the right moment when to use this command during registration process.
Is the value valid before successfull registration to the carrier? Maybe I can call this command only after the modem registers to the carrier. And since I can not register, CSQ returns 0.

On the other hand if CSQ is OK to be called at any time, does this mean that my carrier does not have any cell tower in range? Or none of three available carriers (from COPS) has?

Antenna is connected. The modem lays on my desk on cardboard. There should not be any interference.

herbert.pan-Q · April 12, 2021, 12:18pm

Hi Ishuan:
I’m sorry that the above suggestions didn’t solve your problem.I’m also willing to help you out with your problems.Based on your description, I suggest you troubleshoot your problem in the following ways:
1、If NB is supported locally, the BC66 module also has signal strength under normal conditions without SIM card.and I did the same test without inserting the SIM card**(+CSQ: 19,0)**.Conversely, if NB is not supported locally or the SIM card provider does not support NB service, BC66 will definitely not receive the signal.
Do you have any other BC66 modules? Please do cross-test（Including antenna）. If other devices have the same problem, we suspect that NB may not be supported locally or your SIM Card Provider does not support NB.
2、If there are any other NB service providers in your area？I suggest you change the SIM card of other providers，and repeat the same test,check the result.
3、Please do not lock the frequency band, and execute AT+QSCLK=0 on the BC66. Let the device search bands the network for a long time and track the search situation. Under normal circumstances, all the frequency bands can be searched within 40 minutes.
I hope the above suggestions can solve your problem. If the problem still cannot be solved, I hope we can keep communicating with each other in time,thank you!

herbert.pan-Q · April 12, 2021, 12:44pm

Sorry, I need to add that your location may be too far away from the NB service provider’s base station Leading to BC66 module can not receive the base station signal strength;so,You should ask your local NB provider to perform NB signal testing at the your site location;
or BC66 does not support the frequency set by the local NB service provider.

rastik · April 28, 2021, 6:17pm

Hi, could you please send the first 5 number of IMSI? AT+CIMI will return it.
But if you’re trying to connect to 23002 NB-IoT network, I don’t think it will work. So far, I haven’t seen any of their eNodeB supporting NB-IoT. Only 23001 and 23003.

herbert.pan-Q · April 29, 2021, 1:01am

hi,rastik:

23001, “PAEGAS”, “CZ”
23002, “EUROTEL”, “CZ”
23003, “OSKAR”, “CZ”

You can ask the “Eurotel” telecom operator for advice, if NB is supported in your area!

rastik · April 29, 2021, 7:05am

@ishuan:
As mentioned already - I don’t think O2 is supporting NB-IoT now.

herbert.pan-Q · April 29, 2021, 8:28am

Hi,rastik:
According to the PLMN you provided (MCC[230]+MNC[01,02,03]), I have checked the corresponding telecom operator for you. If you use the NB network of the corresponding telecom operator, you need to consult whether they provide NB.

rastik · April 29, 2021, 8:54am

It is @ishuan who has the problem.

ishuan · April 29, 2021, 12:51pm

To be honest, it seems that carrier O2 does not support NB-IOT at all. However it does not stop them from advertising it on their website and from selling “NB-IOT ready” SIM cards. It’s just scam on users, because their SIM cards are regular LTE cards.

I am sorry for wasting your time. Combination of my amateurism and misleading information from the carrier lead me to spend two weeks debugging this.

Thank you for your time.

rastik · April 29, 2021, 1:09pm

If you need NB-IoT in CZ go for Vodafone - they have nationwide coverage and it just works. And roaming is already active for many countries.

rastik · May 3, 2021, 4:15pm

I stand corrected - O2 CZ has recently deployed NB-IoT on some of their eNodeBs. But I expect you’d need special SIM card with NB services allowed.