Hardware Installation
18
LED Displays
AT-3600 Series hubs have two types of LED displays:
❑
Hub status indicators show the overall condition of the module.
❑
Port indicators show the condition of each port connection. They
vary with module type; later chapters of this manual give specifics.
Hub Status Indicators
The LEDs shown in Figure 17 appear on the back panel of each AT-3600
Series hub.
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.
The AT-3612T has additional hub indicators; see Chapter 6 for details.
Figure 17:
Hub Status LEDs
STATUS
POWER
MASTER
FAULT
