https://devzone.nordicsemi.com/f/nordic-q-a/16950/what-is-uuid-and-handleHello, I want to clear things up a bit, all these concepts are starting to overwhelm me somehow. I want to know: What can have UUID and handle? I understand that profiles and characteristics usually have UUID, but strangely not services. Why, sinceen-USTelligent Community 13Mon, 10 Oct 2016 08:33:00 GMThttps://devzone.nordicsemi.com/thread/64987?ContentTypeID=1Mon, 10 Oct 2016 08:33:00 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b8a413df-9cff-4091-898b-8c4d79c88a6fFormerMember<p>A profile consists of a set of services with a set of characteristics. A profile doesn&#39;t have any UUID since it is defined by the set or subset of services present in a device. All services and characteristics are defined by UUIDs. When a device is advertising, it will advertise the UUID of some or all of its services. <a href="https://www.youtube.com/watch?v=pLgnHuGI69s">This</a> video tutorial talks a little bit about UUIDs from approximately 8:57 to 10:20.</p> <p>During service and characteristic discovery, each service and characteristic are assigned with handle to identify them in the application code. It can be useful to take a look at the documentation of <a href="http://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.sdk5.v12.0.0%2Flib_ble_db_discovery.html&amp;cp=4_0_0_3_1_2">the DB discovery module</a> along with a central example like ble_app_hrs_c for instance.</p><div style="clear:both;"></div>