https://devzone.nordicsemi.com/f/nordic-q-a/18461/how-does-nrf51xxx-mcus-add-services-chara-etcTo my very limited knowledge, it has something to do with an &quot;attribute table&quot; of some sort. So you will have an init function, where you get to write all your attributes inside so when an android phone connects to it, it can discover all the characteristicsen-USTelligent Community 13Mon, 19 Dec 2016 08:49:38 GMThttps://devzone.nordicsemi.com/thread/71231?ContentTypeID=1Mon, 19 Dec 2016 08:49:38 GMT137ad170-7792-4731-bb38-c0d22fbe4515:e9f37001-93e2-4b2e-bad6-53a75295b8c8J&#248;rgen Holmefjord<p>Hi,</p> <p>I would recommend that you read and work through the <a href="https://devzone.nordicsemi.com/tutorials/8">BLE Services</a> and <a href="https://devzone.nordicsemi.com/tutorials/17">BLE Characteristics</a> tutorials found in the <a href="https://devzone.nordicsemi.com/tutorials/">tutorials section</a> here at DevZone. These give a great introduction and should get you started on understanding services and characteristics.</p> <p>Best regards,</p> <p>Jørgen</p><div style="clear:both;"></div>