Android: Bluetooth Serial (Com Port) communication with Android Phone

I am trying to communicate with a Bluetooth programmable Microcontroller. The Bluetooth device on the microcontroller communicates (specifically) on Bluetooth Serial COM Port number 4.

QUESTION: How can I get the Android App to read data from this COM port (number 4)?

I know the UUID is a well known unique ID,that works for this device, but I don't think that it has anything to do with specifying the COM port.

static final UUID myUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
btSocket = btDevice.createRfcommSocketToServiceRecord( myUUID);
btSocket.connect();
valid.append( btDevice.getName() + "\n" + btDevice.getAddress());
north.append("Socket Connected");
InputStream mmInStream = btSocket.getInputStream();
OutputStream mmOutStream = btSocket.getOutputStream();
byte[] buffer = new byte[10];
int bytes;
StringBuffer str = new StringBuffer();
while (true)                            {                               
     try {
    mmOutStream.write("a".getBytes());

        //Reads a # of bytes until the end of stream is reached
        bytes = mmInStream.read(buffer);
        //Transform to string
                str.append(buffer.toString()+"\t");                         //Clear the buffer
        Log.e("DATA", "THE DATA: "+ str.toString());
        south.setText(str.toString());
         str.delete(0,str.length());
       } catch (IOException e) {
        break;
} }}