GM02S attach to different PLMN than requested

LTE-M / NB-IoT (Monarch)
1

We’re observing issues throughout our fleet where we ask modem to manually attach to a specific PLMN but in the end it decides on its own to attach to a different one.

We’re using Mobile operator Emnify which is a MVNO that offers connectivity in Canada through Telus, Rogers, Videotron, Sasktel. But most notably, it does not support Bell. This will be relevant further down below.

Here, we’re trying to attach to Videotron (MCCMNC 302500) but the device will outright just attach to Rogers (MCCMNC 302720) seemlessly.

<AT>
AT+CFUN=4
OK
AT+SQNCCID?
+SQNCCID:"89883030000127997937","89044045117727494800000473424360"
OK
AT+CFUN=1
OK
+CEREG:2
AT+COPS=2
OK
+CEREG:5,"61B2","0190AD15",7
+CEREG:0
AT+CGATT=0
OK
AT+COPS=?
+COPS:(1,"TELUS","TELUS","302220",7)(1,"Videotron","CANVT","302500",7)(2,"RogersWireless","ROGERS","302720",7)(1,"Bell","Bell","302610",7),,(0,1,2,3,4),(0,1,2)
OK
AT+COPS=1,2,"302500",7
OK
+CEREG:2
+CEREG:5,"61B2","0190AD15",7
AT+COPS?
+COPS:1,2,"302720",7
OK
AT+CEREG?
+CEREG:2,5,"61B2","0190AD15",7
OK
AT+CEER
+CEER:lastEmmCause:NOCAUSERECEIVED,lastEsmCause:NOCAUSERECEIVED
OK
AT+SQNMONI=9
+SQNMONI:RogersWirelessCc:302Nc:720RSRP:-94.70CINR:14.30RSRQ:-10.40TAC:25010Id:354EARFCN:5060PWR:-76.52PAGING:128CID:0x190AD15BAND:0
OK
ATI
SEQUANSCommunications
GM02S
UE8.2.0.2
OK

In the specific geographical location where test was concluded, all PLMNs are emitting from the same location and on bands in the lower range of the spectrum (700MHz and such, rural area). What I want to say is I’m ruling out Videotron having a too weak signal to attach.

This issue isn’t limited to this combo of PLMN. We’re also having issues trying to attach to Telus (302220) where even if we submit an AT+COPS=1 command with Telus’ MCCMNC, at some locations, the modem seems to silently try to attach to Bell instead. Since our carrier does not support Bell, it gets rejected (we see it on Emnify’s device portal event logger), and will then attach to Telus, but this causes a significant delay while trying to attach; sometimes upward of 25 seconds which sometimes result in connectivity failure because of our aggressive power saving logic as our device is battery operated.

So my questions are as follow:

  • Why does the modem decide on its own to attach to a different PLMN than the one supplied in manual attach?

  • Is there a way to configure the modem to attach to supplied PLMN and not decide to attach to another one?

    Thanks

2

Hello Benjamin,

We need additional log to further investigate this issue. Here are steps to collect logs:

  1. Download SQN DM light tool and user guide (URL: DM Light)

  2. Install the tool on host PC

  3. Start log by following the user guide.

  4. Execute the manual PLMN selection scenario

  5. Stop the log share the .evt file with us

This will help us to understand what is going on at modem when command is issued.

Thank you!

3

Sorry for the delay.

Do you have a Linux native version of DMLight by the way?

Here is the attached event log file along with the log transcription of DMLight software. It is 100% reproducible where I am. I never was able to connect to PLMN 302500 even though it is supported by our MVNO.

359197351904132_2026-08-28-11h24m04.evt (309.9 KB)



11:24:05'075.00 ATI0
11:24:05'077.41 SEQUANS Communications
11:24:05'077.80 GM02S
11:24:05'078.20 UE8.2.0.2
11:24:05'106.28 ATI1
11:24:05'108.54 UE8.2.0.2
11:24:05'109.11 LR8.2.0.2-59200
11:24:05'138.29 ATI2
11:24:05'140.70 SERIAL: 2GG2312280695008
11:24:05'141.25 IMEISV: 3591973519041315
11:24:05'169.51 AT+CGSN
11:24:05'171.49 +CGSN: 359197351904132
11:24:05'172.93 359197351904132

OK
11:24:05'216.81 AT+BIND?
11:24:05'219.04 +BIND: UART0, "AT"
11:24:05'219.59 +BIND: UART1, "DCP"
11:24:05'220.14 +BIND: UART2, "CONSOLE"
11:24:05'248.49 AT+SQNMODEACTIVE?
11:24:05'251.39 1
11:24:05'295.70 AT+SQNCTM?
11:24:05'339.76 standard
11:24:05'375.83 AT+SQNBANDSEL?
11:24:05'435.65 +SQNBANDSEL: 0,3gpp-conformance,""
11:24:05'436.26 +SQNBANDSEL: 0,att,"2,4,12"
11:24:05'436.84 +SQNBANDSEL: 0,docomo,"1,19"
11:24:05'437.42 +SQNBANDSEL: 0,kddi,"18,26"
11:24:05'437.97 +SQNBANDSEL: 0,standard,"12,13,17"
11:24:05'438.58 +SQNBANDSEL: 0,telstra,"3,28"
11:24:05'439.16 +SQNBANDSEL: 0,tmo,"2,4,5,12,66"
11:24:05'439.77 +SQNBANDSEL: 0,verizon-no-roaming,"4,13"
11:24:05'440.35 +SQNBANDSEL: 0,verizon,"13,4,5,12,17,20"
11:24:05'468.82 AT+CEMODE?
11:24:05'470.62 +CEMODE: 2
11:24:05'533.58 AT+CEREG?
11:24:05'535.38 +CEREG: 2,0
11:24:05'565.77 AT+SQNEDRX?
11:24:05'567.63 +SQNEDRX: 0,4,"1101","0000",1,0
11:24:05'596.87 AT+CPSMS?
11:24:05'598.55 +CPSMS: 0,,,"10100011","00100001"
11:24:05'660.31 AT+CGDCONT?
11:24:05'662.11 +CGDCONT: 1,"IP","em",,,,0,0,0,0,0,0,0,,0
11:24:05'691.90 AT+CGAUTH?
11:24:05'693.73 +CGAUTH: 1,0,"",""
11:24:05'722.84 AT+SQNRMON?
11:24:05'725.22 +SQNRMON: 0,0
11:24:05'754.27 AT+SQNDIT?
11:24:05'756.04 +SQNDIT: 0,0
11:24:27'558.82 AT+CFUN=4
11:24:30'913.19 AT+CIMI
11:24:30'915.14 +CIMI: 295050903596387
11:24:30'916.52 295050903596387

OK
11:24:30'943.89 AT+CNUM
11:24:30'946.52 OK
11:24:30'961.87 AT+SQNCCID?
11:24:30'962.26 +SQNCCID: "89883030000090300580","89044045817727484800000118028931"
11:24:30'975.63 AT+SQNCCID
11:24:30'977.67 +SQNCCID: "89883030000090300580","89044045817727484800000118028931"
11:24:31'071.88 AT+CSCA?
11:24:31'078.01 "+42379010570",145
11:24:35'860.97 AT+CFUN=1
11:24:36'433.00 +CEREG: 2
11:24:38'424.92 AT+COPS=2
11:24:38'145.00 +CEREG: 5,"61B2","0190AD15",7
11:24:39'151.00 +CEREG: 0
11:24:44'386.63 AT+CGATT=0
11:24:46'927.08 AT+CGDCONT?
11:24:46'928.88 +CGDCONT: 1,"IP","em",,,,0,0,0,0,0,0,0,,0
11:24:46'956.68 AT+CGCONTRDP
11:24:46'959.21 OK
11:24:47'973.96 AT+COPS=?
11:24:55'397.62 +COPS=: (2,"Rogers Wireless","ROGERS","302720",7)(1,"TELUS","TELUS","302220",7)(1,"Videotron","CANVT","302500",7)(3,"Bell","Bell","302610",7),,(0,1,2,3,4),(0,1,2)
11:24:59'417.90 AT+COPS=1,2,"302500",7
11:24:59'449.00 +CEREG: 2
11:25:02'281.00 +CEREG: 5,"61B2","0190AD15",7
11:25:07'427.39 AT+COPS?
11:25:07'428.22 +COPS: 1,2,"302720",7
11:25:11'423.29 AT+CGDCONT?
11:25:11'425.12 +CGDCONT: 1,"IP","em",,,,0,0,0,0,0,0,0,,0
11:25:11'454.26 AT+CGCONTRDP
11:25:11'456.43 +CGCONTRDP: +CGCONTRDP: 1,5,"em.mnc005.mcc295.gprs","100.65.0.72.255.255.255.255","","8.8.8.8","8.8.4.4","","",,,,,,,65535
11:25:11'457.86 +CGCONTRDP: 1,5,"em.mnc005.mcc295.gprs","100.65.0.72.255.255.255.255","","8.8.8.8","8.8.4.4","","",,,,,,,65535

OK
11:25:11'843.72 AT+CEREG?
11:25:11'844.27 +CEREG: 2,5,"61B2","0190AD15",7
11:25:15'476.53 AT+CEER
11:25:15'477.26 +CEER: lastEmmCause: NO CAUSE RECEIVED, lastEsmCause: NO CAUSE RECEIVED
11:25:18'529.48 AT+SQNMONI=9
11:25:18'581.29 +SQNMONI: Rogers Wireless Cc:302 Nc:720 RSRP:-95.60 CINR:14.40 RSRQ:-8.00 TAC:25010 Id:354 EARFCN:5060 PWR:-79.82 PAGING:128 CID:0x190AD15 BAND:12 BW:10000 CE:0
11:25:21'983.82 ATI
11:25:21'985.01 SEQUANS Communications
11:25:21'985.62 GM02S
11:25:21'986.20 UE8.2.0.2
4

Hello Benjamin,

Thank you for the logs. Checking internally with R&D and get back to you once we have update.