Cisco Router 7204 Installation And Configuration Manual page 20

Physical Description
The Cisco 7204 router comes equipped with one 280W AC-input or one 280W DC-input power supply.
A fully configured Cisco 7204 router operates with only one installed power supply; however, a second,
optional power supply of the same type provides hot-swappable, load-sharing, redundant power.
Figure 1-3
power supply filler plate is installed over the second power supply bay.)
Do not mix power supplies in the Cisco 7204. In dual power supply router configurations, both power
Caution
supplies must be of the same type (two AC-input power supplies or two DC-input power supplies).
The power supply has the router's main power switch and either an AC-input power receptacle or a
hardwired DC-input power cable (depending on the type of installed power supply).
Adjacent to the power supply bays there are two chassis ground receptacles that provide a chassis ground
connection for ESD equipment or a two-hole grounding lug (refer to
Three internal fans draw cooling air into chassis and across internal components to maintain an
acceptable operating temperature. (Refer to
located in the subchassis.
Caution To ensure the proper flow of cooling air across the internal components, make sure blank port adapters
are installed in unoccupied port adapter slots, and power supply filler plates are installed in unoccupied
power supply bays.
The I/O controller, port adapters, power supplies, and network processing engine slide into their
respective chassis slots and connect directly to the router's midplane; there are no internal cables to
connect. The midplane distributes DC power from the power supplies to the I/O controller, port adapters,
fan tray, and network processing engine.
The midplane also identifies OIR of the port adapters, bridges the PCI buses from the port adapters to
packet static random-access memory (SRAM) on the network processing engine, arbitrates traffic across
the PCI buses, and generates the clock signals for the port adapters on each PCI bus.
The Cisco 7204 operates as either a tabletop or rack-mounted unit. A rack-mount kit is standard
equipment included with all Cisco 7204 routers when they are shipped from the factory. The kit provides
the hardware needed to mount the router in a standard 19-inch equipment rack or a 2-post rack. Steps
for installing the Cisco 7204 router in an equipment rack are explained in
Cisco 7204."
A fully configured Cisco 7204, with two installed power supplies and all chassis slots filled, weighs
approximately 50 pounds (22.7 kilograms [kg]). For clearance requirements and rack-mount installation
considerations, refer to the section "Site Environment" in
Cisco 7204 Installation and Configuration Guide
1-4
shows the rear of a Cisco 7204 router configured with a single AC-input power supply. (A
If you are not rack-mounting your Cisco 7204, place it on a sturdy tabletop or platform.
Figure
Figure 1-3.) The three fans are enclosed in a tray that is
Chapter 2, "Preparing for Installation."
Chapter 1 Product Overview
1-3).
Chapter 3, "Installing the
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