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Cisco ONS 15600 SDH Reference Manual, Release 9.0
78-18400-01
Chapter 1 Shelf and Backplane Hardware
1.10.2 Fan Speed and Failure
Figure 1-13
Air Filter and one Fan Tray Pulled Out
1.10.2 Fan Speed and Failure
If one or more fans fail on the fan-tray assembly, replace the fan tray where that fan resides. You cannot
replace individual fans. The red FAN LED on the front of the fan tray turns on when one or more fans
fail. For fan-tray replacement instructions, refer to the
Cisco ONS 15600 SDH Procedure Guide
. The red
FAN LED clears after you install a working fan tray.
Caution
If both fans in the center fan tray are inoperative, you must replace the fan tray within five minutes of
failure to avoid affecting traffic because CTC software will shut down one of the SSXC cards.
Caution
The ONS 15600 SDH requires at least one working fan in each of the three fan trays. When a single fan
in a tray fails, Cisco recommends replacing the tray with a fully working tray as soon as possible.
Note
Each fan tray contains two fans. The FAN LED indicates if one or both fans fail in that fan tray.
Fan speed is determined by card temperature sensors that report temperature data to the active TSC card.
The sensors measure the input and output air temperature for each card. Fan speed options are low,
medium, and high. For example, if a card exceeds permissible operational temperature, the fan speed
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