nRF9160 DK not responding to the AT commands

[Aydogan]

Hello,

I have been working with the nRF9160 DK to understand AT commands. I tried flashing the Serial LTE Modem application using the Quick Start option in the nRF Connect Desktop application. However, I encountered an error log and was unable to verify the IMEI number or manufacturer of the modem. After flashing the modem, I also attempted to communicate with it using a serial monitor, but it does not respond to AT commands.

As an alternative, I tried flashing the Shell Command Line Interface application onto the board using Quick Start. With this application, I am able to communicate using AT commands. However, in this case, the SIM card (Onomondo) is not recognized by the board (I am using a different SIM card instead of the iBasis card).

I also attempted to recover the board using the "nrfjprog --recover" command, but it did not resolve the issue.

Additionally, I tried flashing the Serial LTE Modem application using the Programmer app in the nRF Connect Desktop, as well as nRF Connect in Visual Studio Code, but encountered the same issues. However, I was able to successfully flash the Blinky and Echo Bot UART applications using the Programmer app and nRF Connect in Visual Studio Code, and both applications function as expected.

Could you help me understand what might be causing the problem with the board? Can I conclude that it is unusable? If so, is there a method to check its usability?

2025-05-12T14:37:46.212Z INFO Initialising the bundled nrfutil device
2025-05-12T14:37:46.219Z DEBUG Started watching devices
2025-05-12T14:37:47.235Z INFO Using the bundled core version for nrfutil device: 8.0.0
2025-05-12T14:37:47.674Z INFO Using nrfutil-device version: 2.7.5
2025-05-12T14:37:47.674Z INFO Using nrf-device-lib version: 0.17.41
2025-05-12T14:37:47.675Z INFO Using nrfjprog DLL version: 10.24.2
2025-05-12T14:37:47.675Z INFO Using JLink version: JLink_V7.94i
2025-05-12T14:37:49.228Z DEBUG Selected device: nRF9160 DK
2025-05-12T14:37:49.259Z DEBUG Changed step: Info
2025-05-12T14:37:50.483Z DEBUG Changed step: Rename
2025-05-12T14:37:51.305Z DEBUG Changed step: Program
2025-05-12T14:40:25.412Z DEBUG Changed step: Verify
2025-05-12T14:40:28.438Z INFO Opened port with options: {"path":"COM13","baudRate":115200}
2025-05-12T14:40:30.440Z ERROR Error: Received ERROR as return value from AT command
2025-05-12T14:40:30.451Z INFO Closed port: COM13
2025-05-12T14:40:53.502Z DEBUG Changed step: SIM
2025-05-12T14:40:55.241Z DEBUG Changed step: Evaluate
2025-05-12T14:40:55.674Z DEBUG Changed step: Learn
2025-05-12T14:40:55.852Z DEBUG Changed step: Develop
2025-05-12T14:40:56.453Z DEBUG Changed step: Apps
2025-05-12T14:40:56.795Z DEBUG Changed step: Finish

[Øyvind]

Hello, 

After flashing the modem, I also attempted to communicate with it using a serial monitor, but it does not respond to AT commands.

Do you get any output at all from the device?

tried flashing the Shell Command Line Interface application onto the board using Quick Start. With this application, I am able to communicate using AT commands. However, in this case, the SIM card (Onomondo) is not recognized by the board (I am using a different SIM card instead of the iBasis card).

This rules out that the board is unusable. The SIM card does not make any difference. 

nRF Connect in Visual Studio Code, and both applications function as expected.

Did you try to program the Serial LTE Modem or the AT Client using the same method? I.e. build the application and flash to the DK?

Kind regards,
Øyvind

[Aydogan]

Hello,

Thank you for your reply.

Øyvind said:

Do you get any output at all from the device?

No, I do not get any response from the device through UART communication.

Øyvind said:

This rules out that the board is unusable. The SIM card does not make any difference. 

Okay, that is good to know.

Øyvind said:

Did you try to program the Serial LTE Modem or the AT Client using the same method? I.e. build the application and flash to the DK?

Yes, I have tried to build and flash the application to the DK, but I get the same result: no response at all.

[Øyvind]

Aydogan said:

No, I do not get any response from the device through UART communication.

But both Blinky and Echo Bot UART applications does give output through UART?

Aydogan said:

I have tried to build and flash the application to the DK, but I get the same result: no response at al

On the nRF9160 DK, is switch SW10 set to nRF91? What is SW9 VDD IO set to?

Aydogan said:

I have tried to build and flash the application to the DK, but I get the same result: no response at all.

Did you build these for the board file nRF9160DK/nrf9160/ns?

You could also test with our precompiled package from the nRF9160DK product page

[Aydogan]

Øyvind said:

But both Blinky and Echo Bot UART applications does give output through UART?

Yes that is correct.

Øyvind said:

On the nRF9160 DK, is switch SW10 set to nRF91? What is SW9 VDD IO set to?

SW10 is set to nRF91 side and SW9 is set to 1V8. I have also tried to 3V position for SW9 and the result did not change.

Øyvind said:

Did you build these for the board file nRF9160DK/nrf9160/ns?

You could also test with our precompiled package from the nRF9160DK product page

Yes, I have built the applications for the nRF9160DK board.

I have flashed the prebuilt file using programmer in nRF Connect but modem still not responding for AT commands.

I am not quite sure if it is different or the same, but I have also tried the prebuilt application located below.

C:\Users\UserFolder\AppData\Roaming\nrfconnect\pc-nrfconnect-cellularmonitor\firmware\slm-with-trace.hex

[Øyvind]

Thanks for confirming. Can you please retry with the serial terminal and provide a screenshot of the serial terminal?  Did you try to press reset button while running SLM in serial terminal?

[Aydogan]

The screenshot of the serial terminal is attached for your review. I also tried pressing the Reset button on the board while serial terminal is connected to the board, but it didn't change anything.

[Øyvind]

Aydogan said:

:\Users\UserFolder\AppData\Roaming\nrfconnect\pc-nrfconnect-cellularmonitor\firmware\slm-with-trace.hex

Did you test with the SLM version included in the precompiled package? 

Aydogan said:

Yes, I have built the applications for the nRF9160DK board.

Did this also include the SLM? Could you test with the AT client sample as well?

Here is what it looks like on my side when programming the Serial LTE Modem application through Quick Start: