https://devzone.nordicsemi.com/f/nordic-q-a/7238/device-link-one-specific-hosthi, as we know, the device need to being linked in 1.28s if Advertising types is BLE_GAP_ADV_TYPE_ADV_DIRECT_IND ,but my host can&#39;t link device in 1.28s,so i want to link specific host by whitelist,but i can&#39;t achieve,i see log by MCP in the followen-USTelligent Community 13Wed, 27 May 2015 12:30:23 GMThttps://devzone.nordicsemi.com/thread/25586?ContentTypeID=1Wed, 27 May 2015 12:30:23 GMT137ad170-7792-4731-bb38-c0d22fbe4515:84f09d47-caef-44b1-917c-4fe444d1a8ccStian R&#248;ed Hafskjold<p>I tried your code and it seems to work fine if I change <code>ble_gap_addr_01.addr_type</code> to <code>BLE_GAP_ADDR_TYPE_PUBLIC</code> . (I&#39;m using MCP with master emulator which advertise with public address). You should also check the order of the bytes, remember it is LSB first.</p> <p>I also think you should set <code>whitelist.irk_count = 0</code></p><div style="clear:both;"></div>