https://devzone.nordicsemi.com/f/nordic-q-a/17707/uart-communicationHi, all. I tested ble_app_uart in example directory by PCA10040 board. It works well. printf (&quot;UART Start!&quot;) in main.c works well. &quot;UART Start&quot; string cames out on putty screen. Then, I ported ble_app_uart to my custom board. My custom boarden-USTelligent Community 13Mon, 14 Nov 2016 10:13:19 GMThttps://devzone.nordicsemi.com/thread/68122?ContentTypeID=1Mon, 14 Nov 2016 10:13:19 GMT137ad170-7792-4731-bb38-c0d22fbe4515:89ff55a4-c121-42cd-9f18-7cbbcd8673d6Stian R&#248;ed Hafskjold<p>Duplicate: <a href="https://devzone.nordicsemi.com/question/102794/uart-communication/">devzone.nordicsemi.com/.../</a></p><div style="clear:both;"></div>