Hi,
I was using the Direct Test mode app from the nRF desktop to try to run a DTM Tx Test on nRF54L15-DK. The app could find the device (but there're two serial ports xxx51/53). I tried both 19200 (recommendation in https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/samples/bluetooth/direct_test_mode/README.html) and 115200 BaudeRate but all had the error of "can't communicate with device".
Attaching the logs here, can you please help to see what's wrong and how should I config? Thanks.
Best regards,
Jianxuan
2026-02-05T01:43:27.389Z INFO Initialising the bundled nrfutil device
2026-02-05T01:43:27.413Z DEBUG Application data folder: /Users/bytedance/Library/Application Support/nrfconnect/pc-nrfconnect-dtm
2026-02-05T01:43:27.469Z DEBUG Sending event "dtm: running nrfutil device"
2026-02-05T01:43:27.469Z DEBUG App pc-nrfconnect-dtm v3.1.0 (official)
2026-02-05T01:43:27.469Z DEBUG App path: /Users/bytedance/.nrfconnect-apps/node_modules/pc-nrfconnect-dtm
2026-02-05T01:43:27.469Z DEBUG nRFConnect 5.2.1, required by the app is (>=5.2.0)
2026-02-05T01:43:27.469Z DEBUG nRFConnect path: /Applications/nRF Connect for Desktop.app/Contents/Resources/app.asar
2026-02-05T01:43:27.469Z DEBUG HomeDir: /Users/bytedance
2026-02-05T01:43:27.469Z DEBUG TmpDir: /var/folders/hb/0xs1gx4j6wbd6h6y9qvcp09c0000gn/T/
2026-02-05T01:43:27.527Z DEBUG Sending event "dtm: running nrfutil device"
2026-02-05T01:43:27.528Z DEBUG Sending event "dtm: running nrfutil device"
2026-02-05T01:43:27.528Z DEBUG Sending event "dtm: running nrfutil device"
2026-02-05T01:43:27.543Z INFO Using the bundled core version for nrfutil device: 8.1.1
2026-02-05T01:43:27.563Z INFO Getting serial port options from the persistent store for 001057747935.pc-nrfconnect-dtm
2026-02-05T01:43:27.564Z INFO Device connected with the serial number 001057747935
2026-02-05T01:43:27.565Z DEBUG Sending event "dtm: device connected"
2026-02-05T01:43:27.645Z INFO Using nrfutil device version: 2.15.7
2026-02-05T01:43:27.645Z INFO Using nrf-device-lib version: 0.22.5
2026-02-05T01:43:27.645Z INFO Using nrf-probe version: 0.51.0
2026-02-05T01:43:27.645Z INFO Using SEGGER J-Link version: JLink_V9.16
2026-02-05T01:43:27.646Z INFO Your version of SEGGER J-Link (9.16) is newer than the one this app was tested with (8.76). The tested version is not required, and your J-Link version will most likely work fine. If you get issues related to J-Link with your devices, use the tested version.
2026-02-05T01:43:32.323Z INFO Selecting device with the serial number 001057747935
2026-02-05T01:43:32.334Z DEBUG Sending event "dtm: running nrfutil device"
2026-02-05T01:43:32.560Z INFO Selected device with the serial number 001057747935
2026-02-05T01:43:32.561Z DEBUG Sending event "dtm: device selected"
2026-02-05T01:43:37.563Z DEBUG DTM Transport: Created
2026-02-05T01:43:37.563Z DEBUG DTM Transport: addListeners
2026-02-05T01:43:37.570Z INFO Running device setup
2026-02-05T01:43:37.570Z DEBUG DTM Transport: Create setup CMD with control: 0
2026-02-05T01:43:37.570Z DEBUG DTM Transport: Create setup CMD with parameter: 0
2026-02-05T01:43:37.570Z DEBUG DTM Transport: Create setup CMD with dc type: 00
2026-02-05T01:43:37.596Z DEBUG DTM Transport: Port Opened
2026-02-05T01:43:37.598Z DEBUG DTM Transport: Sending data: 0x00 0x00
2026-02-05T01:43:38.600Z INFO Cannot communicate with the device. Make sure it is not in use by another application, that the correct serial port has been selected, and that it uses firmware compatible with Direct Test Mode.
2026-02-05T01:43:43.154Z DEBUG DTM Transport: Closing serialport
2026-02-05T01:43:43.156Z DEBUG DTM Transport: Succeeded to close serialport
2026-02-05T01:43:43.156Z DEBUG DTM Transport: Disposed
2026-02-05T01:43:43.156Z DEBUG DTM: disposed
2026-02-05T01:43:43.156Z DEBUG DTM Transport: Created
2026-02-05T01:43:43.156Z DEBUG DTM Transport: addListeners
2026-02-05T01:43:43.165Z INFO Running device setup
2026-02-05T01:43:43.165Z DEBUG DTM Transport: Create setup CMD with control: 0
2026-02-05T01:43:43.165Z DEBUG DTM Transport: Create setup CMD with parameter: 0
2026-02-05T01:43:43.165Z DEBUG DTM Transport: Create setup CMD with dc type: 00
2026-02-05T01:43:43.190Z DEBUG DTM Transport: Port Opened
2026-02-05T01:43:43.190Z DEBUG DTM Transport: Sending data: 0x00 0x00
2026-02-05T01:43:44.191Z INFO Cannot communicate with the device. Make sure it is not in use by another application, that the correct serial port has been selected, and that it uses firmware compatible with Direct Test Mode.
2026-02-05T01:43:49.866Z DEBUG DTM Transport: Closing serialport
2026-02-05T01:43:49.868Z DEBUG DTM Transport: Succeeded to close serialport
2026-02-05T01:43:49.868Z DEBUG DTM Transport: Disposed
2026-02-05T01:43:49.868Z DEBUG DTM: disposed
2026-02-05T01:43:49.868Z DEBUG DTM Transport: Created
2026-02-05T01:43:49.868Z DEBUG DTM Transport: addListeners
2026-02-05T01:43:49.886Z INFO Running device setup
2026-02-05T01:43:49.886Z DEBUG DTM Transport: Create setup CMD with control: 0
2026-02-05T01:43:49.886Z DEBUG DTM Transport: Create setup CMD with parameter: 0
2026-02-05T01:43:49.886Z DEBUG DTM Transport: Create setup CMD with dc type: 00
2026-02-05T01:43:49.912Z DEBUG DTM Transport: Port Opened
2026-02-05T01:43:49.912Z DEBUG DTM Transport: Sending data: 0x00 0x00
2026-02-05T01:43:50.914Z INFO Cannot communicate with the device. Make sure it is not in use by another application, that the correct serial port has been selected, and that it uses firmware compatible with Direct Test Mode.
