https://devzone.nordicsemi.com/f/nordic-q-a/7222/ble-nus---tx-cccd-discoveryHello, I&#39;m trying to retrieve data from a nrf51822-based board that supports the BLE NUS sevice (using the ble_nus Library provided for the uart communication example, and the s110 softdevice). I have a few issues using it: When I try to discoveren-USTelligent Community 13Wed, 27 May 2015 07:58:05 GMThttps://devzone.nordicsemi.com/thread/25508?ContentTypeID=1Wed, 27 May 2015 07:58:05 GMT137ad170-7792-4731-bb38-c0d22fbe4515:9da9c897-92f4-411d-b7c7-4106721b3fa8Robin ANSIAS<p>Indeed, I needed to handle BLE_GATTS_EVT_SYS_ATTR_MISSING (or set the attribute using sd_ble_gatts_sys_attr_set() when a connection occurs). You saved my day, thank you :D</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/25507?ContentTypeID=1Tue, 26 May 2015 07:43:19 GMT137ad170-7792-4731-bb38-c0d22fbe4515:421cd3fd-2f29-4471-8d29-9196f846f076Hung Bui<p>@Robin: Have you tried to use our example ble_app_uart in the SDK ?</p> <p>We also have an example on PC that use Master Emulator API to interface with the UART service. Please look for nRFUart in C:\Program Files (x86)\Nordic Semiconductor\Master Emulator\2.1.12.6\Example code\</p> <p>The reason that service discovery is hung when reading CCCD could be that you haven&#39;t handled BLE_GATTS_EVT_SYS_ATTR_MISSING event in your code. When CCCD is not set, you will receive that event, the softdevice wait for the application to either set it to a previously set value, or set it to NULL.</p><div style="clear:both;"></div>