How many times you had bend on side or back to find if your network cable is plugged in and its blinking ? probably many a times which you don’t want to count. Here is pretty useful software which can make your num lock or scroll lock led blink when there is a network activity i.e. keyboard LEDs (Light Emitting Diode) indicating outgoing and incoming network packets on network interface. Its called as Network Lights

Monitor the synchronization between num lock led and modems activity. ( LINK )

You can check the network stats also and set the configuration for Blink Duration. This works both on Windows Xp and Vista