EXFO FTB-500 - Manual (Page 16)

Introducing the FTB-500
8 FTB-500
LED Indicators Description
LED Indicators Description
The LED panel on the front of the unit provides you with the status of the
FTB-500.
LED Status Meaning
Green Unit is on.
Green, blinking Unit is in Sleep mode.
Off
Unit is off or in Hibernation mode.
(when unit is
connected to an
external power
source)
Green All batteries are fully charged.
Green, blinking At least one battery is charging.
Yellow, blinking No battery present in the unit.
OR
The unit and its modules would be
using more power than what is
available from batteries. Do not
disconnect AC power while this
module is in use.
A blinking yellow LED takes
precedence over a blinking green one,
so when AC power is connected, even
if the LED is blinking yellow, batteries
are probably charging (depending on
conditions).