https://devzone.nordicsemi.com/f/nordic-q-a/121489/serial-lte-modem-at-commands-over-hw-serialHi I&#39;m trying to load a custom board with nrf9160 with the Serial LTE Modem, and route the AT commands to the UART from a coprocessor (ESP32C3) I have followed the guide on using an external MCU: https://docs.nordicsemi.com/bundle/ncs-2.9.0/page/nrf/applicationsen-USTelligent Community 13Thu, 15 May 2025 11:28:17 GMThttps://devzone.nordicsemi.com/thread/535538?ContentTypeID=1Thu, 15 May 2025 11:28:17 GMT137ad170-7792-4731-bb38-c0d22fbe4515:89cc2cd5-8d99-4219-9507-c86830396ba4Kenneth<p>Hello,</p> <p>If you haven&#39;t already you can for instance download the hardware files for the nRF9160-DK here:<br /><a href="https://www.nordicsemi.com/Products/Development-hardware/nRF9160-DK/Download?lang=en#infotabs">https://www.nordicsemi.com/Products/Development-hardware/nRF9160-DK/Download?lang=en#infotabs</a>&nbsp;</p> <p>Also check out the GPIO interfaces description:<br /><a href="https://docs.nordicsemi.com/bundle/ug_nrf9160_dk/page/UG/nrf91_DK/hw_description/if_connector.html">https://docs.nordicsemi.com/bundle/ug_nrf9160_dk/page/UG/nrf91_DK/hw_description/if_connector.html</a></p> <p>Reason for linking to the above is that I suspect the problem may be related to pins are not routed to the pin headers as you expect. You may (at least for test) consider using pins that are routed directly to the pin headers.</p> <p>Kenneth</p><div style="clear:both;"></div>