https://devzone.nordicsemi.com/f/nordic-q-a/46054/nrf9160-at-interface-uart-hardware-relatedHi, I&#39;m trying to make provision for AT command interface in my new nRF9160-SiP based design. Couple of questions related to that: 1) Which UART (nRF9160-SiP pins) should I be using for this purpose? Also - are handshake (RTS, CTS, etc) lines absolutelyen-USTelligent Community 13Thu, 11 Apr 2019 13:08:19 GMThttps://devzone.nordicsemi.com/thread/181620?ContentTypeID=1Thu, 11 Apr 2019 13:08:19 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f72ccb0f-ae60-46d4-bbc6-2aea5f1a685fMartin Lesund<p>Hi Ash,</p> <p>1) The <a href="https://github.com/NordicPlayground/fw-nrfconnect-nrf/blob/master/lib/at_host/at_host.c" rel="noopener noreferrer" target="_blank">AT Host library&nbsp;</a>lets you choose which UART to use. <br />As default it is UART0 and the pins&nbsp;can be&nbsp;<a href="https://www.nordicsemi.com/DocLib/Content/Product_Spec/nRF9160/latest/pin?926#pin_assign" rel="noopener noreferrer" target="_blank">any of the GPIOs.&nbsp;</a></p> <p>For the nRF91 DK for example, the UART0 is using the pins&nbsp;<span>P0.26, P0.27, P0.28, and P0.29 and they are routed to VCOM0.</span></p> <p><em>The RTS, CTS lines are&nbsp;not absolutely needed,&nbsp;but usually recommended.&nbsp;</em></p> <p><em></em></p> <p>2) Please refer to the <a href="https://devzone.nordicsemi.com/b/nrf9160-development-status/posts/nrf9160-development-status" rel="noopener noreferrer" target="_blank">Development Status page</a> on what is supported and what is coming.</p> <p>Please note that the <a href="https://www.nordicsemi.com/DocLib/Content/Product_Spec/nRF9160/latest/nRF9160_html5_keyfeatures" rel="noopener noreferrer" target="_blank">nRF9160 SIP</a>&nbsp;in <strong>not <span style="text-decoration:underline;">just</span> a modem.</strong></p> <p>It has its own Microcontroller with the ARM Cortex M33++, <a href="https://www.nordicsemi.com/DocLib/Content/Product_Spec/nRF9160/latest/nRF9160_html5_keyfeatures" rel="noopener noreferrer" target="_blank">Product Specification</a>.<br /><img src="https://devzone.nordicsemi.com/resized-image/__size/320x240/__key/support-attachments/beef5d1b77644c448dabff31668f3a47-899523bfb156403ba706f25d61f60526/pastedimage1554987859224v1.png" alt=" " /></p> <p><em>The only functionality you would lose if you do not want to interface the nRF9160 SIP with a nRF52840 chip is typical BLE which the nrf52 has.</em></p><div style="clear:both;"></div>