Unable scan and connect to network in VietNam when using SARA R5 with Soracom eSim

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1

Hi team,

I am testing the SARA-R510M8S module with a Soracom eSIM. I scanned for available networks, but none were found, even though I have configured the APN and authentication as follows:

[08:22:07.844] AT+CGDCONT=1,“IP”,“soracom.io”
[08:22:07.864] OK

[08:22:09.885] AT+UAUTHREQ=1,1,“sora”,“sora”
[08:22:09.905] OK

[08:36:36.445] AT+COPS=?
[08:36:36.465]
[08:36:36.465] AT+COPS=?
[08:40:41.705]
[08:40:41.705] +CME ERROR: no network service

However, it is still not working.

I have connected the antenna correctly, and when I tested with a Vietnam carrier’s SIM card, it worked fine. I also removed the SIM card, soldered the eSIM onto the board, and was able to read the ICCID and IMSI, but I still couldn’t find any available networks.

I found a similar issue discussed in this forum thread: Unable to connect the SARA R510M8S module to the network with Hologram SIM, despite correct APN configuration in Vietnam. · Issue #52 · sparkfun/SparkFun_u-blox_SARA-R5_Arduino_Library · GitHub. However, the only suggestion I saw was to update the firmware. I couldn’t find any firmware updates for the SARA-R510M8S-61B-01, and I am currently using firmware version 03.25,A00.02.

Any help would be appreciated.

Thanks
Best regard
Vu.

2

Have you confirmed that the R5 works on the networks available where you are? It’s country/region + carrier dependent (carrier being the phone company)

Does example2 output the expected info? LTE GNSS Breakout - SARA-R5 Hookup Guide - SparkFun Learn

3

Hi TS-Russell ,

Thank you for your respone,

Information:

  1. In my location, only LTE and NB-IoT are supported.
  2. The R5 module supports only LTE-Cat-M1 and NB-IoT.

Test Cases:
:one: Test with a SIM Card of VietNam (Viettel Carrier)**

  • When configuring AT+URAT=8 (NB-IoT), the module connected successfully.
  • When configuring AT+URAT=7 (LTE-Cat-M1), the module failed to connect.

:two: Test with a Soracom eSIM (Viettel Network)**

  • When configuring AT+URAT=8 (NB-IoT) or **AT+URAT=7 (LTE-Cat-M1), the module failed to connect.
  • According to Soracom’s carrier support page, in Vietnam, Soracom only supports Viettel’s 2G and LTE networks**.

Question:
So, is the problem that the Soracom eSIM does not support NB-IoT in my location, where only LTE and NB-IoT are available?

Thanks
Best regard,
Vu.

4

The key points are:

  1. Your location only supports LTE and NB-IoT
  2. The R5 module supports LTE-Cat-M1 and NB-IoT
  3. With Viettel SIM: NB-IoT works, LTE-Cat-M1 doesn’t work
  4. With Soracom eSIM: Neither NB-IoT nor LTE-Cat-M1 works
  5. Soracom’s documentation states they only support Viettel’s 2G and LTE networks in Vietnam

So yes, it appears the problem is that the Soracom eSIM does not support NB-IoT in your location, supported by:

  1. The successful connection of the Viettel SIM on NB-IoT (proving NB-IoT works in your area with your module)
  2. Soracom’s documentation specifically mentioning support for 2G and LTE (but not explicitly mentioning NB-IoT)

It seems that while Soracom uses Viettel’s network, they may only have an agreement to use certain network technologies (2G and regular LTE), but not NB-IoT, despite Viettel offering NB-IoT coverage in your area.

To resolve this, you might need to:

  • Contact Soracom support to confirm if their eSIM should support NB-IoT in Vietnam
  • Consider using a direct Viettel SIM if NB-IoT connectivity is required for your application
1 Like
5

Hi @TS-Russell

Thank you for your advice. I have confirmed with Soracom that NB-IoT is not supported in Vietnam, so I cannot use this plan here.

Could you recommend a SIM module or an eSIM/SIM card that supports global connectivity? I’m new to this, so I’m still quite confused. I really appreciate your help.

Thanks
Best regard
Vu