Figure 12: Switch Id Leds In Low Power Mode - Allied Telesis AT-x550-18XTQ Installation Manual

Chapter 1: Overview
44
The switch displays the letter "F" for fault on the ID LED if it detects one of
the following problems:

A cooling fan has failed.
 The internal temperature of the switch has exceeded the normal
operating range and the switch may shut down.
Note
You can use the SHOW SYSTEM ENVIRONMENT command in the
command line interface to identify the source of the problem.
The states of the LED when the switch is operating in the low power mode
are shown in Figure 12.
The switch is the master switch of a VCStack.
The switch is operating as a stand-alone unit.
The switch is a member switch of a VCStack.
Figure 12. Switch ID LEDs in Low Power Mode