https://devzone.nordicsemi.com/f/nordic-q-a/12211/ble-packet-structurePlease consider the images bellow, which can also be found ​​ here ​ and ​​ here ​. The images represent the structure of a BLE packet, and the units used are bytes. The question I have is regrading the Par/Pay section of the packet. The maximum amounten-USTelligent Community 13Tue, 01 Mar 2016 08:12:01 GMThttps://devzone.nordicsemi.com/thread/46204?ContentTypeID=1Tue, 01 Mar 2016 08:12:01 GMT137ad170-7792-4731-bb38-c0d22fbe4515:6342d045-0c6b-4f83-9f87-af444905589cendnode<p>Well in general you seems to be showing message on top of LE ATT layer where each packet has OP code (what Attribute &quot;method&quot; name is used in this packet) and 2-byte ATT handle (over which record in ATT Server table you communicate). This gives you minimal payload on top of ATT/GATT as 23 - 1 - 2 = 20B. You can see additional explanation at slide 239 and further of LE introduction presentation freely available (upon free registration) at BT SIG pages (see <a href="https://devzone.nordicsemi.com/question/64222/i-am-new-to-the-nrf51-dk-and-would-like-some-insight-on-bluetooth/#64254">this</a> post to get there, your second picture in the question above is &quot;stolen&quot; from there;).</p> <p>Cheers Jan</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/46203?ContentTypeID=1Mon, 29 Feb 2016 17:46:52 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ead789f8-bec5-4b84-be57-886041c7e1c5Petter Myhre<p>If you for example are sending a notificaiton the 2 bytes would be the attribute handle of the characteristic value.</p><div style="clear:both;"></div>