No registration with EM7340 with specific SIM

Hello,

I have a strange behavior of our EM7340 modules when used in combination with a specific SIM card. With one SIM card, LTE registration works fine with the other no registration is possible. Both SIM cards work in other devices (Huawei MediaPad M3 and OnePlus 3). The SIM cards are custom configured and from different vendors. The non-working one is a Gemalto UpTeq Multimedia Ready V.2, the working one is a Anritsu SIM of unknown exact type. I used also qmicli to query various information from the card but could not find a difference between the cards or error indication. Is there any way to find out why the EM7340 does not register?

Known good registration with SIM2:

ati
Manufacturer: Sierra Wireless, Incorporated
Model: EM7430
Revision: SWI9X30C_02.24.05.06 r7040 CARMD-EV-FRMWR2 2017/05/19 06:23:09
MEID: 35907506040317
IMEI: 359075060403176
IMEI SV: 12
FSN: LR709406530310
+GCAP: +CGSM

at!gstatus?
!GSTATUS: 
Current Time:  36               Temperature: 32
Reset Counter: 7                Mode:        ONLINE         
System mode:   LTE              PS state:    Attached     
LTE band:      B28              LTE bw:      10 MHz  
LTE Rx chan:   9260             LTE Tx chan: 27260
LTE CA state:  NOT ASSIGNED
EMM state:     Registered       Normal Service 
RRC state:     RRC Connected  
IMS reg state: No Srv  

PCC RxM RSSI:  -62              RSRP (dBm):  -80
PCC RxD RSSI:  -50              RSRP (dBm):  -67
Tx Power:      0                TAC:         0001 (1)
RSRQ (dB):     -6.0             Cell ID:     01A2D101 (27447553)
SINR (dB):     28.2


OK

No registration with SIM1:

at!gstatus?
!GSTATUS: 
Current Time:  68               Temperature: 30
Reset Counter: 6                Mode:        ONLINE         
System mode:   LTE              PS state:    Not attached 
LTE band:      B28              LTE bw:      10 MHz  
LTE Rx chan:   9260             LTE Tx chan: 4294967295
LTE CA state:  NOT ASSIGNED
EMM state:     Deregistered     Waiting for PDN
RRC state:     RRC Idle       
IMS reg state: No Srv  

PCC RxM RSSI:  -56              RSRP (dBm):  -80
PCC RxD RSSI:  -44              RSRP (dBm):  -67
Tx Power:      0                TAC:         0001 (1)
RSRQ (dB):     -5.8             Cell ID:     01A2D101 (27447553)
SINR (dB):     27.6

Hi,

I am guessing that the unit is in Australia given that you are on band 28? No matter.

Try the below commands to see if you can get an error cause out of the unit, it will also give a bit more information about what is around it.

ati
at+cmee=1
at+cpin?
at+cimi
at+cops?
at+cops=?
at+cops=1,2,"xxxxx",7

In the above the xxxxx is the MNC and MCC returned by the cops=? command before it.

Regards

Matt

Thanks for your answer. The behavior is the same with B7.

ati
Manufacturer: Sierra Wireless, Incorporated
Model: EM7430
Revision: SWI9X30C_02.24.05.06 r7040 CARMD-EV-FRMWR2 2017/05/19 06:23:09
MEID: 35907506040317
IMEI: 359075060403176
IMEI SV: 12
FSN: LR709406530310
+GCAP: +CGSM


OK
at+cmee=1
OK
at+cpin?
+CPIN: READY

OK
at+cimi
001010001

OK
at+cops?
+COPS: 0

OK
at+cops=?
+cops: (1,"lorem","lorem","00101",7),(3... ---snip---

OK
at+cops=1,2,"00101",7

It then hangs. I cancelled it after 30 minutes.

That ones difficult to figure out as we would need to be able to see the layer 3 messaging between the unit and the network (might be a SIM thing as well). If you are doing this on Linux you need to use the dmcapture tool that comes with the QMI SDK (its only a bash script, you don’t need to run QMI to take the log file) or SWILog with Windows.

You then need to pass it back through your commercial/support channel for them to be analysed with the QC tools.

Regards

Matt

./dmcapture.sh -l -d /dev/ttyUSB0 -o log.txt

Does not produce any log and log.txt remains at 0 bytes. I followed the SDK guide and compiled the gobinet and gobiserial modules with debug enabled and did the checks described. The devices and interface are operational. The documentation available on this tool is very limited. It seems just to dump the DM serial port outputs. But the port seems silent even if the card is transferring data and having successful registration. I could not find the SWILog inside the Windows driver directory nor on the website, where can I find it?

Hi,

Second time lucky writing a response to the posting.

The reason you are not seeing anything come out is because I do not think you are applying a filter using the -f switch, there is a sub directory to the dmcapture one giving some of the common ones, the standard one though that i think you need is ‘MC7xxx_GSM_GPRS_EDGE_WCDMA_LTE_DATA_EVDO_SMS.sqf’.

So the test procedure should be

  1. Power unit up let it enumerate.
  2. Set to low power mode with at+cfun=0
  3. Start logging using something like
./dmcapture -d /dev/ttyUSB0 -f filter/MC7xxx_GSM_GPRS_EDGE_WCDMA_LTE_DATA_EVDO_SMS.sqf -o logfile.raw

.
4. Set to full power mode with at+cfun=1
5. Recreate the issue.
6. Set to low power mode (at+cfun=0).
7. Stop the logging.

This should result in a log file that can be converted (you will not see anything in it which is decipherable) and analysed.

Regards

Matt

Thank you for your support. I was able to fix the issue. It was due to the APN Access List (ACL) file on the SIM. Some devices seem to ignore it, so they work. Not sure if the EM7340 respects this field or how it reacts on it. I think the field was properly defining a “default” APN which in turn should work. But maybe it was malformed. When the ACL is disabled via the UST or EST, everything is fine.

Wow that’s low level, thanks for letting me know as its a new one on me. Who helped you figure it out in the end? Or did you figure it out yourself?

Regards

Matt

We have test equipment here and luckily able to figure it out ourselves. Do you know how the EM7340 is designed to handle this SIM card setting?

I’m afraid I do not it would require a level of knowledge that probably only exists within Qualcomm (and some log files).

Regards

Matt