A GPS tracer application for Windows Mobile CE 5

using System;
using System.Collections.Generic;
using System.Text;
using System.Threading;
using System.IO.Ports;


namespace GpsTracer
{
    public class reader 
    {
        static private System.IO.Ports.SerialPort m_serialPort1;
        static private Thread m_th=null;
        static private bool m_run=false;
        static public String m_readed="";
        static private String m_port;
        static private bool m_demo;
        public delegate void DataReceivedEventHandler(string data);
        public event DataReceivedEventHandler dataReceived;

        public reader(String port)
        {
         m_port = port;
        }

        public void start(bool demo)
        {
            m_demo = demo;
            

            if (m_th == null)
            {
                if(!demo && m_serialPort1==null)
                {
                    m_serialPort1 = new System.IO.Ports.SerialPort(m_port);
                }
                m_th = new Thread(methodTh);
            }
            m_run = true;
            m_th.Start();
        }

        public void stop()
        {
            m_run = false;
            Thread.Sleep(500);
            if (!m_demo)
            {
                m_serialPort1.Close();
            }
            if (m_th != null)
            {
                m_th.Abort();
                m_th = null;
            }
        }

        

        private void methodTh()
        {
            if (!m_demo)
            {
                m_serialPort1.Open();
            }

            byte[] buffer= new byte[100];
            while (m_run)
            {
                Thread.Sleep(1000);
                if (m_demo)
                {
                    dataReceived(randomString());
                }
                else
                {
                    m_readed = m_serialPort1.ReadLine();
                    if (m_readed.Length > 0)
                    {
                        dataReceived(m_readed);
                    }
                }
            }
        }

        private String randomString()
        { 
            Random r = new Random();
            String rSecond1 = (int)(r.NextDouble() * 10 - 1) + "" + (int)(r.NextDouble() * 10 - 1) + "" + (int)(r.NextDouble() * 10 - 1) + "" + (int)(r.NextDouble() * 10 - 1);
            String rSecond2 = (int)(r.NextDouble() * 10 - 1) + "" + (int)(r.NextDouble() * 10 - 1) + "" + (int)(r.NextDouble() * 10 - 1) + "" + (int)(r.NextDouble() * 10 - 1);
            String rPrime1 = (int)(r.NextDouble() * 1 - 1) + "";
            String rPrime2 = (int)(r.NextDouble() * 1 - 1) + "";
            
            return "$GPRMC,170111,A,434"+ rPrime1 + "." + rSecond1+",N,0111" + rPrime2 + "." + rSecond2+",W,000.0,360.0,060199,017.5,W*73";
         }
    }
}