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Cisco Catalyst 4900M Switch Installation Guide
78-18350-01
Chapter 1 Product Overview
Switch Components
Chassis Cooling
Note For environmental specifications, see Chapter 2, “Site Planning.”
The hot-swappable system fan tray provides cooling air for the internal chassis
components. The fans exhaust air to the left, and fres h air is drawn in from the
right side of the chassis.
Caution When the fan tray is removed, internal circuitry is exposed that should not be
touched by tools or fingers. The system should not be left operating without a fan
tray for longer than is necessary to replace a faulty fan tray with a new one.
Figure 1-7 shows the direction of airflow going in and out of the switch.
Port
(front)
Green
Yell ow
Flashing yellow
Off
Port is operational
Port is disabled by user
Power-on self-test indicates faulty port
No signal detected or link configuration
failure
Fan (front
and rear)
Off
Green
Red
No power to the switch or fans (the tray may
not be plugged in especially if one or more of
the power supplies status LED is green)
Fan tray operational
Fault detected
PS1 and
PS2
(front)
Off
Green
Red
No power to the PS
Operational1
Fault detected or the on/off switch is set to
off while the power supply is plugged in
1. If either LED is green and the other is OFF the power supply is probably not plugged in. If it is
red, the supply is either plugged in and not switched on or it is faulty. It may be necessary to
interrogate the system for further status using the CLI.
Table 1-1 LED Descriptions (continued)
LED Color or State Description