Bluetooth connect without pairing

The normal way to connect to a bluetooth device is by pairing.

We need to connect to a device in an abnormal way: By using the Bluetooth MAC address only. We do not want to be prompted for a PIN.

We know the device supports this technique, but we cannot find a way to do it on Android.

The abbreviated code looks like this:

  String mac_address = “00:11:22:33:44:55”
  BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

  BluetoothDevice bluetoothDevice = mBluetoothAdapter.getRemoteDevice(mac_address);

  Method m = bluetoothDevice.getClass().getMethod("createRfcommSocket", 
           new Class[] {int.class});
  BluetoothSocket socket = (BluetoothSocket) m.invoke(device, 1);

  socket.connect();

The problem is that upon socket.connect() we are prompted for a PIN. The PIN is not necessary for this device, so we do not want to be prompted for a PIN.

The reason we know the PIN is not necessary:

1. We manufacture this device and write the firmware.
2. We can connect to it using a program on windows written in C#.

How can we modify the code such that it will not prompt for a PIN?

[Edit to test suggestion in comment]

We tested method createInsecureRfcommSocketToServiceRecord like this:

ParcelUuid list[] = device.getUuids();
BluetoothSocket  socket = bluetoothDevice.createInsecureRfcommSocketToServiceRecord(list[0].getUuid());

Then we get error like this:

I/InputDispatcher(  382): Delivering touch to current input target: action: 0x1
I/InputDispatcher(  382): Delivering touch to current input target: action: 0x1
V/BluetoothSocket.cpp(16956): initSocketNative
V/BluetoothSocket.cpp(16956): ...fd 66 created (RFCOMM, lm = 0)
V/BluetoothSocket.cpp(16956): initSocketFromFdNative
I/BluetoothPolicyService(  382): getBluetoothDataTransferAllowed
D/BluetoothUtils(16956): isSocketAllowedBySecurityPolicy start : device null
V/BluetoothService.cpp(  382): createDeviceNative
V/BluetoothService.cpp(  382): ... address =
V/BluetoothEventLoop.cpp(  382): onCreateDeviceResult
V/BluetoothEventLoop.cpp(  382): onCreateDeviceResult
E/BluetoothEventLoop.cpp(  382): onCreateDeviceResult: D-Bus error: org.bluez.Error.AlreadyExists (Already Exists)
D/BluetoothEventLoop(  382): Result of onCreateDeviceResult:1
V/BluetoothService.cpp(  382): discoverServicesNative
V/BluetoothService.cpp(  382): ... Object Path = /org/bluez/1100/hci0/dev_00_11_22_33_44_55
V/BluetoothService.cpp(  382): ... Pattern = , strlen = 0
D/FStest  (  633): check default
D/FStest  (  633): check default