https://devzone.nordicsemi.com/f/nordic-q-a/33255/write-to-characteristic-from-centralHi, I&#39;m having trouble writing to a characteristic when operating as a central. I&#39;m sure it is just a lack of understanding on my part but neither the SDK documentation nor the examples I have seen are helping resolve this. I have successfully manageden-USTelligent Community 13Wed, 11 Apr 2018 09:12:37 GMThttps://devzone.nordicsemi.com/thread/127770?ContentTypeID=1Wed, 11 Apr 2018 09:12:37 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c85da4fa-f017-4e02-93c8-b83a318ea360YYZ<p>Thanks Daniel. That has fixed the problem - really appreciate your help!</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/127689?ContentTypeID=1Tue, 10 Apr 2018 18:19:04 GMT137ad170-7792-4731-bb38-c0d22fbe4515:9d494955-6602-4f0a-b6a4-2ef020dcdf12Daniel Wang[quote userid="26748" url="~/f/nordic-q-a/33255/write-to-characteristic-from-central"]I&#39;ve used the same code in another project when sending data from a peripheral back to a central without problems. Is this correct when trying to write from a central or is this totally wrong?[/quote] <p>It is totally wrong if your central is the client(which is almost always the case). You can&#39;t send a notification from client to server.</p> <p><img alt=" " src="https://devzone.nordicsemi.com/resized-image/__size/640x240/__key/communityserver-discussions-components-files/4/8037.data_5F00_transfer.png" /></p> <p>You should send a write command instead using&nbsp;sd_ble_gattc_write() with opcode&nbsp;BLE_GATT_OP_WRITE_CMD.</p> <p></p><div style="clear:both;"></div>