Chapter 2
Overview
Note
10/100 Port Status LEDs
78-14944-03
In dual-power mode, the switch draws power from the power supply with the
higher voltage. If the primary power supply fails in dual-power mode, the
alternate power supply gives power to the switch.
The power status LEDs show whether the individual power supplies are receiving
power and functioning properly.
Table 2-1
lists the LED colors and meanings.
The power status LEDs show that power is not present on the switch if the power
input drops below 17 V. The power status LEDs only show that power is present
if the voltage at the switch input exceeds 18.5 V. The 1.5 V difference, or
hysteresis, ensures that the power status LEDs do not oscillate at values near 18 V.
In dual-power mode, the power status LEDs show status for both power inputs,
VA and VB.
Table 2-1
Power Status LEDs
Color
System Status
Off
System is not powered up.
Green
Power present on associated contact.
Red
Power not present on associated contact.
For information about the power LED colors during the power-on self-test
(POST), see the
"Powering On the Switch and Running POST" section on
page
3-13.
Each 10/100 port has a port status LED, also called a port LED, shown in
Figure 2-7
and
Figure
the individual ports, shown in
2-8. These LEDs display information about the switch and
Table
2-2.
Catalyst 2955 Hardware Installation Guide
Front-Panel Description
2-13