https://devzone.nordicsemi.com/f/nordic-q-a/44913/which-is-the-call-back-for-ble-custom-characteristic-value-readHi all, At Peripheral end, I will get an callback &quot;BLE_GATTS_EVT_WRITE&quot; whenever I do a write on charcteristic write value from Mobile App. Can you please point me to the callback need to be registered for the read of charcteristic write value fromen-USTelligent Community 13Mon, 18 Mar 2019 12:32:47 GMThttps://devzone.nordicsemi.com/thread/176694?ContentTypeID=1Mon, 18 Mar 2019 12:32:47 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f9261d26-f218-4696-a456-9241a0513abbKenneth<p>Hello,</p> <p>You can find the message sequence charts the events that will occur:<br /><a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s132.api.v6.1.0/s132_msc_overview.html?cp=2_3_1_1_0_1">http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s132.api.v6.1.0/s132_msc_overview.html?cp=2_3_1_1_0_1</a>&nbsp;</p> <p>Typically you will not be informed of any event when a peer read a characteristic, unless you enable authorization on the characteristic, then you will get an event every time the peer try to read the characteristic:<br /><a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s132.api.v6.1.0/group___b_l_e___g_a_t_t_s___r_e_a_d___r_e_q___a_u_t_h___m_s_c.html">http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s132.api.v6.1.0/group___b_l_e___g_a_t_t_s___r_e_a_d___r_e_q___a_u_t_h___m_s_c.html</a>&nbsp;</p> <p>You can transfer any kind of data, just cast the data to (uint8) and then&nbsp;convert it back afterwards.</p> <p>Best regards,<br />Kenneth</p><div style="clear:both;"></div>