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Cisco Catalyst 4900M Switch Installation Guide
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Chapter 1 Product Overview
Switch Components
The Catalyst 4900M switch has two redundant internal 1000 W AC or
1000 W DC power supplies.
The internal power supplies have individual power cords and status LEDs (PS1
and PS2 on the front panel). There are also LEDs on the power su pplies that show
status for the input (Input OK) and output (Output OK) currents. A power cord i s
used to connect the power supplies to the site AC power sour ce. There is a power
switch on the AC Catalyst 4900M switch power supplies; AC power is present
when a power cord is plugged into a power supply and the switch is set to the On
position. DC power supplies do not use a power supply cord or have an on/off
switch.
The switch starts with only one power supply plugged in, but redunda nt failover
and load sharing is not available in this configuration. Cisco recommends that you
always connect both power supplies to separate AC or DC circuits for optimal
power reliability.
For safety reasons, the AC power supply must be switched off and unplugged
before it is removed from a chassis or inserted into a chassis. DC supplies should
have power shut off from the source before they are removed.
If only one power supply is used, you must use the blank faceplate supplied to
cover the empty power bay.
Environmental Monitoring of the Power SuppliesUsing the environmental monitoring and reporting functions, you can maintain
normal system operation by resolving adverse environmental conditions prior to
loss of operation.
Each power supply monitors its own temperature and output voltages. The
Catalyst 4900M switch senses the operating condition of the power supply and
reports status through software.
Power Management for the Catalyst 4900M SwitchYou can select AC or DC power supplies for your switch. The Catalyst 4900M
switch supports the following power supplies:
• 1000 W AC
• 1000 W DC