Setting 3G only mode on MC7455

IoT Modules MC/EM Series
1

I am using a MC7455 module in a WE826-T2 router. I cannot receive a 4G signal indoors but get quite good 3G. I tried the router outside and the modem uses LTE, but the rate is very poor.

I have tried to use 3G only using the software setting in the openWRT router software but this was not permanent, when I used it outside it went to LTE.

So I tried using AT commands * AT!ENTERCND="A710"
then * AT!SELRAT=01
and * AT!BAND=00
exit * AT!RESET

This appears to work until I go outside and LTE is connected instead of 3G.

I am using the latest GENERIC firmware in QMI mode.

2

Hi @charlie_boy

Which firmware version are you using? If you are not in the latest firmware, please download the latest one and retry.
https://source.sierrawireless.com/resources/airprime/minicard/74xx/airprime-em_mc74xx-approved-fw-packages/#sthash.JmLdHQ7l.dpbs

This issue has not been reproduced on MC7455 firmware Generic SWI9X30C_02.33.03.00 at my side.
I go outside and MC7455 is only connected 3G (WCDMA) with AT!SELRAT=01 (UMTS 3G Only).
Log file is attached for your reference.MC7455.txt (5.0 KB)

Please help to mark “Solution” if your questions is answered.

3

Hi, I can reproduce your findings inside the house (But the connection is lost in the process). And if I unplug the router and go outside it will force LTE.

The 3G setting does not persist. I will go through the procedure again.

Okay I tried it again and the unit went to 3G only. Then I unplugged the unit and it returned to automatic. No need to go outside.

Try disconnecting power. Then turning on again.

Are settings supposed to revert to default automatic after power is removed?

upload.txt (1.1 KB)

4

Another thing I have noticed is that if I switch to 3G Only then I lose my connectivity which then forces me to remove power which in turn removes the 3G Only settings.

That places me in the unfortunate position of not being able to use an external antenna, It forces me to use it inside the house.

Outside I will be forced to use LTE and if I do alter that to 3G Only via AT commands or the router then it loses my signal.

Rebooting rooter and reset via router do not help. I get a failure to connect retrying message.

I need these AT commands to stick even when power is removed. That is my only hope of using external antenna.

This is the output I get when my connection is lost.updated.txt (1.3 KB)

5

I think I have finally managed though debug is still showing that I am in automatic mode but it no longer forces LTE outside.

I used:
AT!ENTERCND=“A710”
AT!SELRAT=01
AT!BAND=01
AT!RESET

6

Hi charlie_boy

If the module’s current band setting is not compatible with the selected RAT, an appropriate band will be selected automatically and set on the modem.
You can force AT!SELRAT=01 and AT!BAND=01 for only 3G.

Could you please provide some information about your module using below commands?
AT!ENTERCND=“A710”
ATI3
AT!SELRAT=01
AT!BAND=01
AT!RESET
Power is removed/plugged in
AT!ENTERCND=“A710”
AT!SELRAT?
AT!BAND?
AT!GSTATUS?

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7

The command AT!ENTERCND=“A710” gives:
AT!ENTERCND=“A710”
ERROR

Entered again AT!ENTERCND=“A710” Gives
AT!ENTERCND=“A710”
OK

Entered:ATI3 Gives:
ATI3
Manufacturer: Sierra Wireless, Incorporated
Model: MC7455
Revision: SWI9X30C_02.33.03.00 r8209 CARMD-EV-FRMWR2 2019/08/28 20:59:30
MEID: 35907206183919
IMEI: 359072061839193
IMEI SV: 20
FSN: LQ806470220210
+GCAP: +CGSM,+DS,+ES
OK

Entered: AT!SELRAT=01 Gives
AT!SELRAT=01
OK

Entered: AT!BAND=01 Gives:
AT!BAND=01
OK

Entered: AT!RESET Gives:
AT!RESET
OK

Disconnected power cable and plugged back in.

Entered: AT!ENTERCND=“A710” Gives:
AT!ENTERCND=“A710”
ERROR

Entered: AT!ENTERCND=“A710” Gives:
AT!ENTERCND=“A710”
ERROR

Entered: AT!ENTERCND=“A710” Gives:
AT!ENTERCND=“A710”
OK

Entered: AT!SELRAT? Gives:
AT!SELRAT?
!SELRAT: 00, Automatic
OK

Entered: AT!BAND? Gives:
AT!BAND?
Index, Name, GW Band Mask L Band Mask TDS Band Mask
01, Europe 3G, 0002000000400000 0000000000000000 0000000000000000
OK

Entered: AT!GSTATUS? Gives:
AT!GSTATUS?
!GSTATUS:
Current Time: 751 Temperature: 42
Reset Counter: 1 Mode: ONLINE
System mode: WCDMA PS state: Attached
WCDMA band: WCDMA 2100
WCDMA channel: 10564
GMM (PS) state:REGISTERED NORMAL SERVICE
MM (CS) state: IDLE NORMAL SERVICE

WCDMA L1 state:L1M_DCH LAC: 0039 (57)
RRC state: CELL_DCH UTRAN Cell ID: 00B0018C (11534732)
RxM RSSI C0: -73 RxD RSSI C0: —
RxM RSSI C1: -72 RxD RSSI C1: —
OK

8

Hi @charlie_boy

You can meet only 3G network.

It reverts to default automatic (!SELRAT: 00, Automatic) after disconnected power cable and plugged back in.
This issue has not been reproduced with FW 02.33.03 MC7455 at my side.
Log file is attached for your reference. MC7455_2105.txt (3.9 KB)

You can try to do these steps as below:
1.Clear all firmware entries and NVUs:
AT!ENTERCND=“A710”
AT!IMAGE=0
AT!RESET
2.Download the latest firmware (SWI9X30C_02.33.03.00) to the module
3. Set image management preferences
AT!ENTERCND=“A710”
AT!IMPREF=“GENERIC”
AT!RESET
4.Provide some information about your module using below commands
AT!ENTERCND=“A710”
AT!IMPREF?
AT!IMAGE?
AT!SELRAT=01
AT!BAND=01
Disconnected power cable and plugged back in.
AT!ENTERCND=“A710”
AT!SELRAT?
AT!BAND?
AT!GSTATUS?

1 Like
9

Okay I have done that results below:

Entered: AT!ENTERCND=“A710”
Response:AT!ENTERCND=“A710”
OK

Entered: AT!IMPREF?
Response: AT!IMPREF?
!IMPREF:
preferred fw version: 02.33.03.00
preferred carrier name: GENERIC
preferred config name: GENERIC_002.072_000
preferred subpri index: 000
current fw version: 02.33.03.00
current carrier name: GENERIC
current config name: GENERIC_002.072_000
current subpri index: 000

OK

Entered: AT!IMAGE?
Response: AT!IMAGE?
TYPE SLOT STATUS LRU FAILURES UNIQUE_ID BUILD_ID
FW 1 GOOD 1 0 0 ?? 02.33.03.00?
FW 2 EMPTY 0 0 0
FW 3 EMPTY 0 0 0
FW 4 EMPTY 0 0 0
Max FW images: 4
Active FW image is at slot 1

TYPE SLOT STATUS LRU FAILURES UNIQUE_ID BUILD_ID
PRI FF GOOD 0 0 0 002.072_000 02.33.03.00_GENERIC
Max PRI images: 50

OK

Entered: AT!SELRAT=01
Response: AT!SELRAT=01
OK

Entered: AT!BAND=01
AT!BAND=01
OK

Disconnected power and plugged back in:

Entered: AT!ENTERCND=“A710”
Response: AT!ENTERCND=“A710”
OK

Entered: AT!SELRAT?
Response: AT!SELRAT?
!SELRAT: Unknown RAT mode. Use AT!SELRAT to set band.
00000046
00000000

OK

Entered: AT!BAND?
Response: AT!BAND?
Index, Name, GW Band Mask L Band Mask TDS Band Mask
01, Europe 3G, 0002000000400000 0000000000000000 0000000000000000

OK

Entered: AT!GSTATUS?
Response: AT!GSTATUS?
!GSTATUS:
Current Time: 664 Temperature: 40
Reset Counter: 1 Mode: ONLINE
System mode: WCDMA PS state: Attached
WCDMA band: WCDMA 2100
WCDMA channel: 10588
GMM (PS) state:REGISTERED NORMAL SERVICE
MM (CS) state: IDLE NORMAL SERVICE

WCDMA L1 state:L1M_FACH LAC: 0039 (57)
RRC state: CELL_FACH UTRAN Cell ID: 00B0145C (11539548)
RxM RSSI C0: -66 RxD RSSI C0: —
RxM RSSI C1: — RxD RSSI C1: —

OK

10

Hi @charlie_boy

You can meet only 3G network.

It reverts to default automatic (!SELRAT: 00, Automatic) after disconnected power cable and plugged back in.
This issues has been reproduced on a specific module at your side.
In your case, the best way is to get support through your commercial channel (i/.e. who you bought the unit from.).

11

Hi, were you able to reproduce my problem at your side?

Is this a firmware issue or hardware problem?

I bought the unit overseas.

12

Hi @charlie_boy

No, I wasn’t. I have attached log file before.

Please contact your technical support in SWI to provide you the solution in this case. Then you can provide trace and AT log file for further investigation.

13

Please contact your technical support in SWI to provide you the solution in this case. Then you can provide trace and AT log file for further investigation.

What is “SWI”?

14

Hi @charlie_boy

SWI is Sierra Wireless.

The best way is to get support through your commercial channel (i/.e. who you bought the unit from) in this case.