MC7700 works one time, then stops registering with the network

IoT Modules
1

I have 3 MC7700 and they all exhibit the same behaviour. The first time they’re plugged in and configured, they connect for a few minutes. Then, the network disconnects and I can’t get them to connect again.

This happens regardless which network I use, and I’ve seen a different forum post online claiming the same behaviour in a different country.

For debugging purposes, I’ll use the MC7700 with the latest firmware available:


Manufacturer: Sierra Wireless, Incorporated
Model: MC7700
Revision: SWI9200X_03.05.29.03ap r6485 CNSHZ-ED-XP0031 2014/12/02
OK


at!gstatus?
!GSTATUS: 
Current Time:  662              Temperature: 32
Bootup Time:   651              Mode:        ONLINE         
System mode:   WCDMA            PS state:    Not attached 
WCDMA band:    WCDMA 850  
WCDMA channel: 4433
GMM (PS) state:DEREGISTERED     PLMN SEARCH    
MM (CS) state: IDLE             PLMN SEARCH    

WCDMA L1 State:L1M_ACQ          LAC:         0000 (0)
RRC State:     DISCONNECTED     Cell ID:     00000000 (0)
RxM RSSI C0:    ---             RxD RSSI C0: -106
RxM RSSI C1:   -106             RxD RSSI C1: -106


OK

at!gstatus?
!GSTATUS: 
Current Time:  1047             Temperature: 33
Bootup Time:   895              Mode:        ONLINE         
System mode:   LTE              PS state:    Not attached 
LTE band:      B4               LTE bw:      3 MHz   
LTE Rx chan:   2223             LTE Tx chan: 65535
EMM state:     Deregistered     Attach Needed  
EMM connection:RRC Idle       

RSSI (dBm):    0                Tx Power:    0
RSRP (dBm):    0                TAC:         0000 (0)
RSRQ (dB):     0                Cell ID:     00000000 (0)
SINR (dB):     -20.0


OK
at!gstatus?
!GSTATUS: 
Current Time:  1058             Temperature: 33
Bootup Time:   895              Mode:        ONLINE         
System mode:   WCDMA            PS state:    Not attached 
WCDMA band:    WCDMA 850  
WCDMA channel: 4376
GMM (PS) state:DEREGISTERED     PLMN SEARCH    
MM (CS) state: IDLE             PLMN SEARCH    

WCDMA L1 State:L1M_ACQ          LAC:         0000 (0)
RRC State:     DISCONNECTED     Cell ID:     00000000 (0)
RxM RSSI C0:    ---             RxD RSSI C0: -106
RxM RSSI C1:   -106             RxD RSSI C1: -106


OK

!GSTATUS: 
Current Time:  1353             Temperature: 33
Bootup Time:   1205             Mode:        ONLINE         
System mode:   WCDMA            PS state:    Not attached 
WCDMA band:    WCDMA 2100 
WCDMA channel: 10737
GMM (PS) state:DEREGISTERED     PLMN SEARCH    
MM (CS) state: IDLE             PLMN SEARCH    

WCDMA L1 State:L1M_ACQ          LAC:         0000 (0)
RRC State:     DISCONNECTED     Cell ID:     00000000 (0)
RxM RSSI C0:    ---             RxD RSSI C0: -106
RxM RSSI C1:   -106             RxD RSSI C1: -106


OK

!GSTATUS: 
Current Time:  1455             Temperature: 32
Bootup Time:   1440             Mode:        ONLINE         
System mode:   LTE              PS state:    Not attached 
LTE band:      B17              LTE bw:      5 MHz   
LTE Rx chan:   5821             LTE Tx chan: 65535
EMM state:     Deregistered     Attach Needed  
EMM connection:RRC Idle       

RSSI (dBm):    0                Tx Power:    0
RSRP (dBm):    0                TAC:         0000 (0)
RSRQ (dB):     0                Cell ID:     00000000 (0)
SINR (dB):     -20.0


OK

The GSM operator is Orange Romania, and their APN is “net” Orange - Romania APN settings - APN.how

+CGDCONT: 1,"IP","net","0.0.0.0",0,0
+CGDCONT: 2,"IP","net","0.0.0.0",0,0
+CGDCONT: 16,"IPV4V6","net","0.0.0.0",0,0

OK

The SIM card I’m testing with works with EM7455, it’s my personal one I used in this thread the other day: EM7455 not registering with the network - #26 by mihai

Other debugging details:

at!band=?
Index, Name
00, All bands                     
01, Europe 3G                     
02, North America 3G              
03, Europe 2G                     
04, North America 2G              
05, GSM ALL                       
06, Europe                        
07, North America                 
08, WCDMA ALL                     
09, LTE ALL                       

OK

at!band?
Index, Name,                        GW Band Mask     L Band Mask
00, All bands,                      000000000CE80380 0000000000010009


OK
2

MC7700 supports LTE B1/B4/B17, seems no such band for your operator “orange Romania”

3

Forgot to check that, thank you!

4

While I can’t explain why it worked one time with Orange (perhaps roaming?), I’ve swapped to a Telekom Romania SIM and restricted to B1, since the Telekom network exhibits the same behaviour, works once then stops:


!GSTATUS: 
Current Time:  1248		Temperature: 31
Bootup Time:   241		Mode:        ONLINE         
System mode:   LTE          	PS state:    Not attached 
LTE band:      B1     		LTE bw:      15 MHz  
LTE Rx chan:   75		LTE Tx chan: 65535
EMM state:     Deregistered   	Attach Needed  
EMM connection:RRC Idle       

RSSI (dBm):    -81		Tx Power:    0
RSRP (dBm):    -112		TAC:         1B5A (7002)
RSRQ (dB):     -13		Cell ID:     0201FC15 (33684501)
SINR (dB):     -1.4


OK

The APN is “broadband” as per Telekom Romania - Romania APN settings - APN.how

+CGDCONT: 1,"IP","broadband","0.0.0.0",0,0
+CGDCONT: 2,"IP","broadband","0.0.0.0",0,0
+CGDCONT: 16,"IPV4V6","broadband","0.
5

not sure if you can use MC7700 in Europe as it is not GCF certified.

6

Are you referring to the legality, the physical possibility or the IMEIs possibly being blocked? There are others using MC7700 in Romania, for example, thread MC7700 + Panasonic CF19K => 4G No Service :(

7

I just think that it does not make sense to connect once only…

then did you try with Digi?

8

Telekom SIM, doesn’t work anymore after working a few days ago:

!GSTATUS: 
Current Time:  249		Temperature: 30
Bootup Time:   1		Mode:        ONLINE         
System mode:   LTE          	PS state:    Not attached 
LTE band:      B1     		LTE bw:      15 MHz  
LTE Rx chan:   75		LTE Tx chan: 18075
EMM state:     Deregistered   	Attach Needed  
EMM connection:RRC Idle       

RSSI (dBm):    -85		Tx Power:    0
RSRP (dBm):    -117		TAC:         1B5A (7002)
RSRQ (dB):     -13		Cell ID:     0201FC15 (33684501)
SINR (dB):     -2.2


OK

Digi SIM, connected right now:

at!gstatus?
!GSTATUS: 
Current Time:  22		Temperature: 31
Bootup Time:   1		Mode:        ONLINE         
System mode:   LTE          	PS state:    Attached     
LTE band:      B1     		LTE bw:      15 MHz  
LTE Rx chan:   75		LTE Tx chan: 18075
EMM state:     Registered     	Normal Service 
EMM connection:RRC Idle       

RSSI (dBm):    -83		Tx Power:    0
RSRP (dBm):    -115		TAC:         1B5A (7002)
RSRQ (dB):     -13		Cell ID:     0201FC15 (33684501)
SINR (dB):     -2.6


OK

I expect Digi will stop working soon, too, should I run any other diag commands while it’s working?

9

i don’t know what information you should get as it seems it is the network to block the module

10

Well, Digi has stopped working, too:

!GSTATUS: 
Current Time:  66		Temperature: 31
Bootup Time:   43		Mode:        ONLINE         
System mode:   LTE          	PS state:    Not attached 
LTE band:      B1     		LTE bw:      15 MHz  
LTE Rx chan:   75		LTE Tx chan: 18500
EMM state:     Deregistered   	Attach Needed  
EMM connection:RRC Idle       

RSSI (dBm):    -88		Tx Power:    0
RSRP (dBm):    -122		TAC:         5AC3 (23235)
RSRQ (dB):     -20		Cell ID:     0E0BBF15 (235650837)
SINR (dB):     -3.8


OK

I’m not sure it’s a network block, but I’d love to know how to test for it. It’s too much of a coincidence for 3 separate MC7700 devices to exhibit the same behaviour (work once with each network, stop working a few minutes after).

If I wait a couple of weeks, they’ll do the same thing again, work once with each network and then stop working.

11

have you checked with the network operator?
Especially this module is not GCF certified

12

My experience with each of their customer support has been “if it’s not a phone we’re selling on our website or a modern phone, we can’t help you”, but I’ll fire off an email to a business contact, might as well.

If anything other than “we’re not blocking any IMEI” comes up, I’ll reply here.

Thank you for your time!