MC7455 missing SIM

IoT Modules MC/EM Series
1

Hello community,

I’m trying to get a MC7455 module work with the APU3C4 embedded board, but it keeps giving “missing-sim” error.

# mmcli -m 0
  --------------------------
  General  |      dbus path: /org/freedesktop/ModemManager1/Modem/0
           |      device id: ff59d5ef8de8bbf3d51211662ec732a7851651dd
  --------------------------
  Hardware |   manufacturer: Sierra Wireless, Incorporated
           |          model: MC7455
           |       revision: SWI9X30C_02.33.03.00
           |   h/w revision: MC7455
           |      supported: gsm-umts, lte
           |        current: gsm-umts, lte
           |   equipment id: 001027009999999
  --------------------------
  System   |         device: /sys/devices/pci0000:00/0000:00:13.0/usb3/3-1/3-1.3
           |        drivers: qcserial, cdc_mbim
           |         plugin: Sierra
           |   primary port: cdc-wdm0
           |          ports: ttyUSB0 (qcdm), ttyUSB2 (at), cdc-wdm0 (mbim), 
           |                 wwp0s19u1u3i12 (net)
  --------------------------
  Status   |          state: failed
           |  failed reason: sim-missing
           |    power state: low
           | signal quality: 0% (cached)
  --------------------------
  Modes    |      supported: allowed: 3g; preferred: none
           |                 allowed: 4g; preferred: none
           |                 allowed: 3g, 4g; preferred: 3g
           |                 allowed: 3g, 4g; preferred: 4g
           |        current: allowed: any; preferred: none
  --------------------------
  Bands    |      supported: utran-1, utran-3, utran-4, utran-5, utran-8, utran-2, 
           |                 eutran-1, eutran-2, eutran-3, eutran-4, eutran-5, eutran-7, eutran-8, 
           |                 eutran-12, eutran-13, eutran-20, eutran-25, eutran-41
  --------------------------
  IP       |      supported: ipv4, ipv6, ipv4v6

At first, I suspected that the integrated SIM slot of the board was faulty, so I ordered a small SIM adapter, which allows to attach the SIM directly to the module. But the module is still not recognizing the SIM…

Usim-sim-card-socket-slot-solderless-holder-For-mini-pci-e-module-3G-WWAN-Modem

Could anyone take a look at the schematics of the embedded board and tell me if there’s any incompatibility between the board and the module? I’m starting to think it might be physically not compatible.

Schematics (J15, USB only – SIM 1, Page 8): https://pcengines.ch/schema/apu3c.pdf

Also, if anybody has an experience with this particular module and Debian 10.3 (Buster), please tell me if there’s anything special with the combination.

I’d very much appreciate your help.

Best regards,

shohta

2

Hi @shohta ,

Could you please share the log file to me with these commands as below after inserted the SIM card to the module.

AT!RESET
AT+CCID
AT+CPIN?

3

@shohta,

I would make sure by asking the unit through AT commands (not expecting a different response but just to make sure. Send the below to it using minicom (or some other terminal program).

ati
at+cpin? //If this responds with READY then it can see the SIM

If it does not then it has not detected/been able to electrically interact with the SIM and it is going to be a hardware issue somewhere as the interface is pretty robust and able to talk to most SIM/USIM/eUICC’s.

Regards

Matt

4

Thank you @Donald, here is the output of the commands:

AT!RESET                                                                        
OK                                                                              
AT                                                                       
OK                                                                              
AT                                                                              
OK                                                                              
AT+CCID                                                                         
+CME ERROR: SIM failure                                                         
AT+CPIN?                                                                        
+CME ERROR: SIM not inserted
5

Hi @mlw, thank you for your comment. Here’s the output of the commands:

ATI                                                                             
Manufacturer: Sierra Wireless, Incorporated                                     
Model: MC7455                                                                   
Revision: SWI9X30C_02.33.03.00 r8209 CARMD-EV-FRMWR2 2019/08/28 20:59:30        
IMEI: 001027009999999                                                           
IMEI SV: 20                                                                     
FSN: LQ831146030210                                                             
+GCAP: +CGSM                                                                    
                                                                                
                                                                                
OK                                                                              
AT+CPIN?                                                                        
+CME ERROR: SIM not inserted

Do you know why it’s showing the strange IMEI? On the module, some other IMEI (356526071633469) is printed.

6

@shohta,

So the IMEI number is very odd and according to the systems does not line up with any form of MC7455 from what I can see, neither does the serial number.

I don’t know the origin of the unit but I suggest you send it back to your commercial channel to have iot replaced, assuming it is under warranty as it doesn’t look right to me.

Regards

Matt

7

Dear @mlw,

Thank you for your swift response. To be honest, I’m not entirely sure any more, whether if the unit is authentic… I got it from some random seller on aliexpress and payed something like 80 USD. Maybe they sold me some kind of fake :frowning: It is rather difficult to find somebody who sells MC7455 to individual consumers in Switzerland.

Anyway I’m sorry for having wasted your time, I’ll look for some way to buy a genuine unit.

Thank you again for your help, have a good rest of the day :slight_smile:

Regards,

shohta

8

@shohta,

I would look at Digikey, we supply to them explicitly specifically because they do sell in ones and two, hold stock and ship globally within 24 hours.

Regards

Matt

9

Dear @mlw,

Thank you very much for your suggestion. I’ll go ahead and order one from them :slight_smile:

Have a lovely day!

Regards,

shohta