https://devzone.nordicsemi.com/f/nordic-q-a/16972/ble_gap_conn_sec_mode_setGiven this answer , do the BLE_GAP_CONN_SEC_MODE_SET family of macros only relate to the Write permissions of the device name? Maybe a better way to ask this is: Is it just incidental that the only characteristic that has adjustable permissions inen-USTelligent Community 13Tue, 11 Oct 2016 07:29:26 GMThttps://devzone.nordicsemi.com/thread/65107?ContentTypeID=1Tue, 11 Oct 2016 07:29:26 GMT137ad170-7792-4731-bb38-c0d22fbe4515:a6507eef-fe06-4636-b841-37e2db393671FormerMember<p>The BLE_GAP_CONN_SEC_MODE_SET_xxx macros are, according to their documentation, GAP attribute security requirement setters, see ble_gap.h. The macros can be used to set the read and write permissions on attribute properties. In ble_app_hrs --&gt; battery service, the client is not allowed to write battery level characteristic, and it is set the following way: <code>BLE_GAP_CONN_SEC_MODE_SET_NO_ACCESS(&amp;attr_md.write_perm);</code></p> <p>In the <a href="http://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.s132.api.v3.0.0%2Fgroup___b_l_e___g_a_p___f_u_n_c_t_i_o_n_s.html&amp;cp=2_3_0_1_0_2_1_2_15&amp;anchor=gae779f7eed346027dc4cbaf438352e5db">sd_ble_gap_device_name_set(..)</a> documentation it is specified that the first parameter is the write permissions for the device name. And hence, setting <code>BLE_GAP_CONN_SEC_MODE_SET_NO_ACCESS(&amp;sec_mode);</code>will set the write permissions.</p><div style="clear:both;"></div>