How to use Keyboard's LED to indicate Network Activity?

This is old trick but new to Break The security.  I hope that you have seen three LED lights in your keyboard, for indicating NUM lock, Scroll and Caps lock.  You can use those LED lights for indicating Network activity. Using this trick, we can make the Num and Scroll lock LED for indication.  These LED will start to blink whenever there is data transfer(send or receive packets on network) being