https://devzone.nordicsemi.com/f/nordic-q-a/16746/write-to-characteristic-with-manual-ackHi all, I believe it should be possible to defined a characteristic which can be written to but have no automatic write response ACK sent. Instead I want to send a manual ACK once I have processed the written data on the micro-controller received viaen-USTelligent Community 13Mon, 03 Oct 2016 13:07:06 GMThttps://devzone.nordicsemi.com/thread/64020?ContentTypeID=1Mon, 03 Oct 2016 13:07:06 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7e596419-58b0-4124-b6ad-354c5bbce443Hung Bui<p>Hi Simon,</p> <p>I believe that the nRF8001 can only handle authorization (application choose to ACK or NACK) with write request.</p> <p>So you need to make sure you don&#39;t check &quot;write without response&quot; when you configure the nRF8001. And that your client write with write request, not write command.</p> <p>Also, please make sure you handle all DATA event. Because if you missed the first DataReceivedEvent, and don&#39;t send a response either SendDataAck or SendDataNack then you won&#39;t receive any further Data event.</p> <p>A <a href="https://www.nordicsemi.com/eng/Products/Bluetooth-Smart-Bluetooth-low-energy/nRF-Sniffer/">sniffer trace</a> would be useful to see what happened over the air.</p> <p>Best Regards,</p> <p>Hung</p><div style="clear:both;"></div>