https://devzone.nordicsemi.com/f/nordic-q-a/106001/dtm-ota-commandsHello, If I use nRF Connect on Android Device and connect to an nRF52840 DUT, I can see an unknown service 0xFD10. Clicking that expands, and I can see UUID 0xFD14. Clicking up arrow on that one I can issue DTM commands over-the-air. Then, issuingen-USTelligent Community 13Thu, 23 Nov 2023 13:36:19 GMThttps://devzone.nordicsemi.com/thread/457178?ContentTypeID=1Thu, 23 Nov 2023 13:36:19 GMT137ad170-7792-4731-bb38-c0d22fbe4515:51e940e6-09d2-44d9-b269-07a832f5d009Hung Bui<p>Hi Timo,&nbsp;</p> <p>Could you please give more information about the firmware you flashed on the&nbsp;nRF52840 ?&nbsp;<br />You can find the DTM protocol defined at Part F in Bluetooth Core spec:&nbsp;<a href="https://www.bluetooth.com/specifications/specs/core-specification-5-4/">https://www.bluetooth.com/specifications/specs/core-specification-5-4/</a></p> <p>Another source for studying the DTM protocol is to look at our DTM sample in the SDK (nrf/samples/bluetooth/direct_test_mode)</p><div style="clear:both;"></div>