https://devzone.nordicsemi.com/f/nordic-q-a/5351/about-iot-sdk-can-not-connect-dk-when-i-input-the-commandHi guys, I follow the steps of and everything was ok before executing the connect command. I can see the MAC address with &quot;nCOAP_Client&quot; after I input the hcitool lescan command. Would you please let me know which step may cause this error? Here isen-USTelligent Community 13Mon, 02 Feb 2015 08:39:44 GMThttps://devzone.nordicsemi.com/thread/18692?ContentTypeID=1Mon, 02 Feb 2015 08:39:44 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b97cc2c6-eccf-4e14-a012-723a3a5264b0Lukasz Duda<p>Based on your error message, have you set the PSM number?</p> <pre><code>echo 35 &gt; /sys/kernel/debug/bluetooth/6lowpan_psm </code></pre><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/18691?ContentTypeID=1Sat, 31 Jan 2015 03:47:04 GMT137ad170-7792-4731-bb38-c0d22fbe4515:db3a5d62-31f1-470d-b6ef-dbfe7736cad5foxcc<p>Hi Duda,</p> <p>Thank you. But I follow your command, it returns &quot;bash:echo:write error: Invalid argument&quot;.</p> <p>kind regards.</p> <p>foxcc</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/18690?ContentTypeID=1Fri, 30 Jan 2015 12:16:25 GMT137ad170-7792-4731-bb38-c0d22fbe4515:707e9146-5017-488d-a478-0cdfdafd9389Lukasz Duda<p>Hello foxcc,</p> <p>In your case, the correct syntax is:</p> <pre><code>echo &quot;connect 00:6D:86:8A:41:C4 1&quot; &gt; /sys/kernel/debug/bluetooth/6lowpan_control </code></pre> <p>You have to simply get rid of &quot;&lt;&quot; and &quot;&gt;&quot; characters.</p><div style="clear:both;"></div>