https://devzone.nordicsemi.com/f/nordic-q-a/2786/android-bluetoothsocket-is-blockingThe Android API Kitkat documentation says the following about BluetoothSockect.connect() &quot;This method will block until a connection is made or the connection fails. If this method returns without an exception then this socket is now connected.&quot; en-USTelligent Community 13Fri, 13 Jun 2014 12:52:37 GMThttps://devzone.nordicsemi.com/thread/10720?ContentTypeID=1Fri, 13 Jun 2014 12:52:37 GMT137ad170-7792-4731-bb38-c0d22fbe4515:088ace87-2920-4e00-a725-74b29e3b85dfHung Bui<p>Hi Gilson,</p> <p>BluetoothSocket is for classic Bluetooth (BR/EDR) for Bluetooth Low Energy, please use BluetoothGatt instead. Please follow the documentation <a href="http://developer.android.com/guide/topics/connectivity/bluetooth-le.html">here</a>, and <a href="http://developer.android.com/tools/samples/index.html">the example</a> on Android website or our samples app provided on our website.</p><div style="clear:both;"></div>