https://devzone.nordicsemi.com/f/nordic-q-a/16555/missing-write-event-on-pairingI&#39;m using SDKv12 S132v3 on nRF52 peripheral device. I have characteristic with following security setup: char_add_params.read_access=SEC_JUST_WORKS; char_add_params.write_access=SEC_JUST_WORKS; char_add_params.cccd_write_access=SEC_JUST_WORKS; en-USTelligent Community 13Wed, 21 Sep 2016 12:07:24 GMThttps://devzone.nordicsemi.com/thread/63332?ContentTypeID=1Wed, 21 Sep 2016 12:07:24 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c375eeac-4427-4aea-838d-2b26f751bf79Keton<p>Thanks for clarification.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/63331?ContentTypeID=1Wed, 21 Sep 2016 09:18:23 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f841f1dc-3da3-442a-9e6e-a64adf2d6df8Petter Myhre<p>You are not doing anything wrong.</p> <p>If a client tries to write to an attribute value that requires the link to be in a certain security level, and the link is not in this level, it will receive an error response, and the attribute value will not be written (and the application will not get the write event). This error response is in your case most likely &quot;Insufficient Authentication&quot;, and this error response is used to trigger initiation of pairing by the central device.</p> <p>After pairing is complete the client can try to write again.</p> <p>(Only write requests will get error responses, not write commands)</p><div style="clear:both;"></div>