Fujitsu MB2140 Series Hardware Manual page 22

MESSAGES
Three types of front-panel LEDs on the main unit indicate the following.
POWER LED (Orange) (Silk-printed POWER): The power is on.
READY LED (Green) (Silk-printed READY):
<ON> Both the main unit and host computer are ready for communication.
<Blinking> The main unit is communicating with the host computer.
HARD ERROR LED (Red) (Silk-printed ERROR): A hardware error has occurred.
Caution: A lit HARD ERROR LED means repair is required.
4-3