Quectel RG255C-GL can´t connect to private network 5G SA

IoT Modules 5G Module
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1

We are having problems with the modem Quectel RG255C-GL to connect it to a private 5G SA network. Connecting to a commercial 4G/LTE works without any problems. With the same SIM card and trying to connect to the same network works without any problems when using the modem Quectel RM530N-GL.

The firmware identifier the modem RG255GC-GL is the following:

AT+QGMR
RG255CGLABR01A04M4G_A0.002.A0.002

Could you please help us with this issue we are having? Is the firmware the required version for the modem to connect to a 5G SA network? If there is a newer version of the firmware, could you please provide it to us?

Thank you in advance.

1 Like
2

Dear @ebriseid
For RG255G, it only support 20M bandwidth. Please confirm this.
What is the configuration of network? band and others?
I will sent the firmware to your email, please check later.

3

Hi Silvia.

Thank you for your reply. The 5G SA network we are trying to connect to has a 20 MHz bandwidth (we are aware of this limitation). The band of the network is N40 and the Downlink MIMO mode is 2x2. Is there any other technical specification of the network that is relevant for the modem RG255G and needs to be checked on our side?

Thank you in advance.

4

Hi Silvia.

We have updated the firmware on the modem RG255C-GL to the latest version you have provided:

AT+QGMR
RG255CGLABR01A04M4G_A0.004.A0.004

But it has not solved our problem connecting to the 5G SA network.

Some additional information regarding the configuration of the modem and tests performed:

We configure the modem to 5G NR only:

AT+QNWPREFCFG=“mode_pref”
+QNWPREFCFG: “mode_pref”,NR5G
OK

Set the modem to be data centric:

AT+QNWPREFCFG=“ue_usage_setting”
+QNWPREFCFG: “ue_usage_setting”,1
OK

All the expected networks are shown when searching for available networks:

AT+COPS=?
+COPS: (1,“999 02”,“999 02”,“99902”,12),(3,“Movistar”,“Movistar”,“21407”,7),(3,“Orange SP”,“ESPRT”,“21403”,7),(1,“999 50”,“999 50”,“99950”,12),(3,“Movistar”,“Movistar”,“21407”,12),(1,“999 70”,“999 70”,“99970”,12),(3,“vodafone ES”,“voda ES”,“21401”,7),(0-4),(0-2)
OK

When trying to connnect to our private 5G SA network we always get the error CME ERROR 30:

AT+COPS=1,2,“99902”,12
+CME ERROR: 30

When searching for primary serving cell, the state returned is always SEARCH:

AT+QENG=“servingcell”
+QENG: “servingcell”,“SEARCH”
OK

Could you please help us to find a solution to the problem we are facing with the modem?

5

Dear @ebriseid
Is it possible to capture log for analysis?
If yes, Please include AT+CFUN=0/AT+CFUN=1, and wait a few minites.

6

Hi @silvia

I have captured logs as requested. The logs include the the operations AT+CFUN=0/AT+CFUN=1

The commands that were executed while capturing the log are the following:

AT+COPS=?
+COPS: (1,"999 70","999 70","99970",12),(1,"999 50","999 50","99950",12),(3,"Orange SP","ESPRT","21403",7),(3,"Movistar","Movistar","21407",12),(1,"vodafone ES","voda ES","21401",7),(3,"Movistar","Movistar","21407",7),(3,"YOIGO","YOIGO","21404",7),,(0-4),(0-2)
OK

AT+QNWPREFCFG="mode_pref"
+QNWPREFCFG: "mode_pref",NR5G
OK

AT+COPS=1,2,"99970",12
+CME ERROR: 30

AT+QENG="SERVINGCELL"
+QENG: "servingcell","SEARCH"
OK

AT+CFUN=0
OK
AT+CFUN=1
OK

AT+QENG="SERVINGCELL"
+QENG: "servingcell","SEARCH"
OK

AT+COPS=1,2,"99970",12
+CME ERROR: 30

20250429100654295.zip (112.5 KB)

7

Dear @ebriseid
The log size is small, it seems you don’t execute AT command to enable log output.
Please AT+QCFG=“dbgctl”,0 before test.

8

Hi @silvia

You were right, the AT command was not executed before capturing the log. I apologize for the inconvenience. I have executed the command to enable the log output and captured the log again. The log is available to download in the following link: 20250430110740713.zip - Google ドライブ

9

Dear @ebriseid
I can’t download from google on my side, do you have any ways to download?

10

Hi @silvia

Can you try to download the file from OneDrive/Sharepoint? https://optarecloud-my.sharepoint.com/:u:/g/personal/ebriseid_optaresolutions_com/EVDA9QJWmJ9An0kwxdKQUzYBI_t2sgi5vwwMohfh2ZGbEA?e=kUuQKi

If not, please let me know where I can upload the file so that you are able to download it.

11

Hi @silvia

Have you been able to download the log file from OneDrive/Sharepoint? Any updates on the analysis of the log?

Thank you in advance.

Best regards,
Erik

12

Dear @ebriseid
Sorry for the late.
Engineer checked the log and found the signal is poor, do you contact the antenna correctly ? Is it far from base station?

13

Hi @silvia

I have checked again the antenna connections of the modem and they are correctly connected. The base station is in the same office as where the modem logs were captured, 10 meters away where other modem pick up a strong signal from the same 5G network and base station.

With the modem RG255C-GL and the command AT+QSCAN=2 the signal from the 5G SA network seems to be very good:

AT+QSCAN=2
+QSCAN: "NR5G",999,70,469970,500,-62,-11,79,1
+QSCAN: "NR5G",999,70,476210,4,-54,-11,86,1

When trying to connect to a commercial 4G network with the modem, it can connect without any problems and gets a good signal.

14

Dear @ebriseid
I have sent AT commands to you via Message, please execute and test again.

15

Hi @silvia

I have executed the AT commands and now I can connect to the 5G SA network and I have connectivity to internet with the AT command QPING, as the screenshot shows:

image
image959×593 12.7 KB

The problem I´m currently facing is that I can not establish a connection with the modem in Windows 11 Pro x64. After trying to establish the connection in Windows, after a while it appears with the status “Disconnected”.

I have installed on my laptop the version 2.7 of the NDIS Windows driver.
What configuration is necessary for the modem to work in Windows?

Also tried to connect the modem to a laptop with OS Ubuntu 22.04.5 LTS, but the modem does no seem to be recognized and a connection is not established. On this same laptop the modem RM530N-GL work perfectly and can connect to the 5G SA network without any problems. Is it requiered a specific driver for the modem RG255C-GL on Ubuntu?

Thank you in advance.

16

Dear @ebriseid
For windows, please check usbnet is NDIS via AT+QCFG=“usbnet”.

For linux, do you add the PID and VID to USB driver?
lsusb

17

Hi @silvia

The modem works now correctly in Windows. But I´m still having problems to get the modem to work in Linux. Using AT commands, the modem can connect to the 5G SA network correctly. The problem is when using the modem with Modem Manager. The modem is recognized by the system, but will not connect to the network.

The commands I´ve tried to use to connect to the network are the following:

sudo mmcli --modem 0 --enable
sudo mmcli --modem 0 
sudo mmcli --modem 0 --simple-connect="apn=internet"
sudo nmcli con up modem1

Modem detected by Modem Manager:

$ mmcli -L
    /org/freedesktop/ModemManager1/Modem/0 [Quectel] RG255C-GL

Modem and connection status:

$ mmcli -m 0
  --------------------------------
  General  |                 path: /org/freedesktop/ModemManager1/Modem/0
           |            device id: 124b85f25df06ea956096c1aefabf78b70b30fb2
  --------------------------------
  Hardware |         manufacturer: Quectel
           |                model: RG255C-GL
           |    firmware revision: RG255CGLABR01A04M4G
           |            supported: gsm-umts
           |              current: gsm-umts
           |         equipment id: 864624060087410
  --------------------------------
  System   |               device: /sys/devices/platform/axi/1000120000.pcie/1f00300000.usb/xhci-hcd.1/usb3/3-1
           |              drivers: option
           |               plugin: quectel
           |         primary port: ttyUSB2
           |                ports: ttyUSB2 (at)
  --------------------------------
  Status   |       unlock retries: sim-pin (3), sim-puk (10), sim-pin2 (3), sim-puk2 (10)
           |                state: enabled
           |          power state: on
           |       signal quality: 0% (recent)
  --------------------------------
  Modes    |            supported: allowed: any; preferred: none
           |              current: allowed: any; preferred: none
  --------------------------------
  IP       |            supported: ipv4, ipv6, ipv4v6
  --------------------------------
  3GPP     |                 imei: 864624060087410
           |         registration: idle
           | packet service state: detached
  --------------------------------
  3GPP EPS | ue mode of operation: csps-1
  --------------------------------
  SIM      |     primary sim path: /org/freedesktop/ModemManager1/SIM/0

USB device connected:

$ lsusb
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 002: ID 2c7c:0316 Quectel Wireless Solutions Co., Ltd. RG255C-GL
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

The PID and VID was added to the USB driver with the following command:

sudo -i
modprobe option
echo "2c7c 0316" > /sys/bus/usb-serial/drivers/option1/new_id

The PID and VID was also added to the QMI WAN Driver with the commands below:

sudo -i
modprobe qmi_wwan
echo "2c7c 0316" > /sys/bus/usb/drivers/qmi_wwan/new_id

To my knowledge the modem loads the driver correctly:

$ less /sys/kernel/debug/usb/devices
…………………..
T:  Bus=03 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  2 Spd=480  MxCh= 0
D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=2c7c ProdID=0316 Rev= 5.15
S:  Manufacturer=Quectel
S:  Product=RG255C-GL
S:  SerialNumber=ec3b3f3c
C:* #Ifs= 4 Cfg#= 1 Atr=a0 MxPwr=500mA
I:* If#= 0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=30 Driver=option
E:  Ad=01(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 1 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
E:  Ad=82(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 2 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=40 Driver=option
E:  Ad=84(I) Atr=03(Int.) MxPS=  10 Ivl=32ms
E:  Ad=83(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=03(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 3 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=50 Driver=option
E:  Ad=86(I) Atr=03(Int.) MxPS=   8 Ivl=32ms
E:  Ad=85(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=04(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms

$ dmesg
……………………………..
[  273.347767] usbcore: registered new interface driver usbserial_generic
[  273.347781] usbserial: USB Serial support registered for generic
[  273.355511] usbcore: registered new interface driver option
[  273.355530] usbserial: USB Serial support registered for GSM modem (1-port)
[  279.218033] option 3-1:1.0: GSM modem (1-port) converter detected
[  279.218311] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB0
[  279.218389] option 3-1:1.1: GSM modem (1-port) converter detected
[  279.218463] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB1
[  279.218519] option 3-1:1.2: GSM modem (1-port) converter detected
[  279.218579] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB2
[  279.218632] option 3-1:1.3: GSM modem (1-port) converter detected
[  279.218685] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB3
[  284.642616] usbcore: registered new interface driver cdc_wdm
[  284.646506] usbcore: registered new interface driver qmi_wwan

Could you please help me to configure the modem correctly in Linux?

Thank you in advance.

18

Too late, all the interfaces are already occupied by the option driver.

No, there is no QMI driver loaded by the OS.

Consider upgrading the kernel or unbind If# 3 before loading qmi_wwan.

Alternatively uninstall ModemManager and switch the modem to ECM mode.