Allied Telesis AT-TS24TR - Manual (Page 41)

Hardware Installation
24
LED Displays
TurboStack hubs have two types of LED displays:
❑ Hub status indicators show the overall condition of the module
❑ Port activity indicators show the condition of each port connection.
Port activity indicator designs vary with module type; later
chapters of this manual give specifics.
Hub Status
Indicators
As Figure 20 and Figure 21 show, hub status LEDs appear on both the
back and the front panels of a TurboStack hub.
The specific illumination characteristics of each LED are as follows:
POWER—Green whenever power is applied.
MASTER— Amber indicates the currently active Master. (Illuminates on
the Master or on the Backup when the Backup has taken over the Master
function).
FAULT—(OFF under normal operational conditions):
❑ Stays red for a very short time while power-on/reset diagnostics are
run; remains continually red if a malfunction occurs during the
diagnostics
❑ Turns red (on a Master only) if the Master fails; if the Backup
detects a failure of the Master, the Backup takes over the Master
function
Note
If the Master fails, its software may not be able to turn OFF its own Master
LED; consequently, the Master LED may be illuminated on two modules in
the backplane. In this kind of failure, however, the original Master’s Fault
LED will also be illuminated to indicate the failure.
Figure 21: AT-TS12F/SC Hub
LED Displays
Hub status LEDs
Port activity LEDs