LED indicator blinks in different colors to deliver different notifications to the user:
Blinking RED: The LED indicator blinks red whenever you have incoming or waiting communication messages on your phone - new email, new call or missed
Blinking GREEN: this is Coverage Indicator light. This lets you know you are connected to a network.
Blinking BLUE:If your phone is connected to a Bluetooth device, such as a Bluetooth headset it blinks blue.
Blinking YELLOW: A blinking yellow light means it is time to charge your BlackBerry