https://devzone.nordicsemi.com/f/nordic-q-a/63100/51822-dtm-test-connection-problemhi The serial ports p0.04 and p0.05 on our hardware circuit. We can&#39;t communicate with the board with nRFgo studio after modification. The serial port has been closed. Request technical support! thank!en-USTelligent Community 13Mon, 29 Jun 2020 12:19:05 GMThttps://devzone.nordicsemi.com/thread/257370?ContentTypeID=1Mon, 29 Jun 2020 12:19:05 GMT137ad170-7792-4731-bb38-c0d22fbe4515:dc36933d-9c1d-4a30-802c-de421583d04cKenneth<p>What debugging have you done? Did it work before you modified pins? Have you disabled hardware flow control? Have you done any measurements on the the DTM pins to check if there is any data? Have you repeated the test on an nRF51-DK?</p> <p>Kenneth</p><div style="clear:both;"></div>