Overview of the Cisco 12008
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Vertical cable-management bracket (one per line card)—This bracket is attached to a
line card by means of captive installation screws at the top and bottom of the bracket.
Once an interface cable is connected to its intended line card port, you loop the cable
through the cable keeper clip nearest the port of connection and seat the cable in the
bottom of the bracket raceway.
Thus, the vertical cable-management bracket enables you to neatly "dress" all the
interface cables in place as you connect them to the individual line card ports.
Later, when you remove or replace a line card, you need only disconnect the cables from
the individual line card ports (leaving the cables intact within the vertical cable-
management bracket) and detach the bracket from the line card to be replaced.
When you install the new line card, you merely reattach the vertical cable-management
bracket to the new line card and reconnect the interface cables to the appropriate line
card port(s).
Card Cage Fan Tray
The card cage fan tray is located in the lower card cage behind the air filter assembly (see
Figure 1-2). This fan tray maintains the operating temperature of the router's electronic
circuitry within an acceptable range.
Designed for simplicity, the card cage fan tray incorporates six fans mounted on a sheet
metal carrier. The assembly also contains associated wiring and a connector in the back of
the unit that enables it to draw operating power through the backplane from a DC-DC
converter on the CSC.
Guide rails in the sides of the lower card cage facilitate insertion and removal of the fan tray
assembly, which is secured in place by means of a captive installation screw on each side
of the metal carrier.
Under normal operating conditions, the variable-speed fans in the card cage fan tray operate
at a reduced rate to
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Conserve power
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Reduce noise
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Minimize fan wear
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Cisco 12008 Gigabit Switch Router Installation and Configuration Guide