Hi, I think you are going in wrong direction. Serial port are buffered port and it has got two seperate data line, which are TX (Transmit) and RX(Receive). Now if you send any data to your serial port it's there in TX buffer. So which ever device connected to this serial port suppose to get that. So, you want to see whether this code working for you or not. So do one thing. Get one RS232 connector and short both RX pin and TX pin. Now try the same code, it should work. This is called loopback mechanism in hardware style. If you don't have this connector then there are few utility software which create virtual serial port and same utility can create loopback mechanism also. This is loopback in software style. I am sure either of two approach should solve your problem. Please let me know if you still face issues. Himadri