https://devzone.nordicsemi.com/f/nordic-q-a/39390/nus-message-confirmationDoes the Nordic UART Service (NUS) have a facility to confirm when a sent message has been received by the peer? In particular, to confirm when an NUS message sent by a Central has been received by the Peripheral? Or, conversely, an event to indicateen-USTelligent Community 13Fri, 12 Oct 2018 07:49:49 GMThttps://devzone.nordicsemi.com/thread/152603?ContentTypeID=1Fri, 12 Oct 2018 07:49:49 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7b653329-a6eb-4cb8-a436-6acd5eb6eb85MartinBL<p>There is nothing like that in the NUS service implementation itself. However, if I understand you correctly you should be able to use the&nbsp;<a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s132.api.v6.1.0/group___b_l_e___g_a_t_t_c___e_n_u_m_e_r_a_t_i_o_n_s.html#ggafd9b8b42eeb832d688e33f4561f97efca69bce270587ac00d7a1c3bd976cfd902">BLE_GATTC_EVT_WRITE_CMD_TX_COMPLETE</a>&nbsp;event that is generated after a call to <a title="sd_ble_gattc_write" href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s132.api.v6.1.0/group___b_l_e___g_a_t_t_c___f_u_n_c_t_i_o_n_s.html?cp=2_3_1_1_0_2_2_2_11#ga90298b8dcd8bbe7bbe69d362d1133378">sd_ble_gattc_write</a>(). Please refer to the Message Sequence Charts:&nbsp;<a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s132.api.v6.1.0/group___b_l_e___g_a_t_t_c___v_a_l_u_e___w_r_i_t_e___w_i_t_h_o_u_t___r_e_s_p___m_s_c.html">GATTC Characteristic Value Write Without Response</a>.</p> <p>There is also an equivalent event generated after notifications are sent from the server side:&nbsp;<a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s132.api.v6.1.0/group___b_l_e___g_a_t_t_s___h_v_n___m_s_c.html">GATTS Handle Value Notification</a>.</p><div style="clear:both;"></div>