Cisco XR 12404 - Manual (Page 40)

Chapter 1 Cisco XR 12404 Router Overview
Fan Tray Assembly
1-26
Cisco XR 12404 Router Installation Guide
OL-13830-02
The status LEDs on the DC PEM provide information about the current
operational status of the power supply.
Table 1-10 summarizes the function of
these indicators.
Power Distribution
The backplane distributes power through the Cisco XR 12404 router and to all
cards in the card cage. The PEM converts AC power source into –48 VDC. When
directed by the route processor or by MBus software, the MBus module turns on
the DC-DC converter; the –48 VDC is converted into +2.5 VDC, +3.3 VDC and
+5 VDC for all internal voltages required by the cards.
Power for the fan tray assembly is supplied directly from the backplane. An
internal fan tray assembly controller card converts –48 VDC into DC voltage that
powers the fans.
Fan Tray Assembly
The Cisco XR 12404 router is equipped with a fan tray assembly located at the
side of the chassis. The fan tray assembly maintains acceptable operating
temperatures for the internal components by drawing cooling air across the card
cage.
Table 1-10 DC-Input PEM LED Indicators
LED Label Color Function
Output OK Green PEM is powered on and operating normally.
Input OK Green DC power is present at the PEM input and
within the specified limits.
Output Fail Amber Indicates a failure in the PEM.
todd.book Page 26 Monday, March 16, 2009 2:47 PM