Reading mouse input with Java comm

Hi Folks...

I'm trying to get a Java program together to read the input from a
serial mouse connected to my PC on COM1. This is not the main mouse so
I don't get a port in use exception when I start the program. The
problem is that I get absolutely nothing.

I've constructed this from scraps I've found all over the internet.
I'm using version 2.1.7 of the RXTX comm API hence the 'gnu.io'
package prefixes.

I'd be most grateful if anyone has a suggestion on why this doesn't
work. Or indeed any step I might take to ensure the mouse if connected
properly to the PC.

With thanks in advance,
Steve.

import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;

import java.io.IOException;
import java.io.InputStream;

public final class CommServiceManager {
    public void initialise() throws Exception {
        CommPortIdentifier portId =
CommPortIdentifier.getPortIdentifier("COM1");
        SerialPort serialPort = (SerialPort) portId.open("MouseReader",
2000);
        final InputStream inputStream = serialPort.getInputStream();
        serialPort.addEventListener(new SerialPortEventListener() {
            public void serialEvent(SerialPortEvent evt) {
                if (evt.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
                    byte[] readBuffer = new byte[20];
                    try {
                        while (inputStream.available() > 0)
                            inputStream.read(readBuffer);

                        System.out.println(">>" + new String(readBuffer));
                    } catch (IOException ioe) {
                        ioe.printStackTrace();
                    }
                }
            }
        });

        serialPort.setSerialPortParams(
                9600,
                SerialPort.DATABITS_8,
                SerialPort.STOPBITS_1,
                SerialPort.PARITY_NONE
            );

        serialPort.notifyOnDataAvailable(true);

        serialPort.notifyOnCTS(true);
        serialPort.notifyOnDSR(true);

        serialPort.setDTR(true);
        serialPort.setRTS(true);

        int duration = 1000;
        float pulseRate = 1.28f;
        int numOfPulse = (int) (duration * pulseRate);

        int waitingTime = (int) (1000 / (2 * pulseRate));
        for (int i = 1; i <= numOfPulse * 2; i++) {
            serialPort.setDTR(i % 2 == 1);
            Thread.sleep(waitingTime);
        }
    }

    public static void main(String[] args) {
        try {
            CommServiceManager manager = new CommServiceManager();
            manager.initialise();

            while (true) {
                Thread.sleep(2000);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}