Cisco Systems WS-X6608-T1 用户手册
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Cisco Cat alyst 4900M Sw itch Instal lation Guid e
78-18350-02
Chapter 1 Product Overview
Catalyst 4900M Swi tch Chassis
Figure 1-4
Catalyst 4900M Chassis Airflow
There are five fans in the fan tray. If an in dividual fan fails , the o ther fans co ntinue to run. Senso rs
monitor the internal air temperatures. The number of fan s in operation and their sp eed varies according
to the intern al temperature for the quietest o peration possible. If the air temperature exceeds a desired
thresho ld, the environmental mon itor disp lays warning mes sages.
monitor the internal air temperatures. The number of fan s in operation and their sp eed varies according
to the intern al temperature for the quietest o peration possible. If the air temperature exceeds a desired
thresho ld, the environmental mon itor disp lays warning mes sages.
Note
Ind iv idual fan s in the fan tray canno t be replaced; the entire fan tray must be replaced.
Power Supplies
Note
Fo r co mplete power specification s for th e Catalyst 490 0M s witch, see Appendix A, “
.”
The Catalyst 4900M switch has two redu ndant in ternal 1 000 W AC-input or 10 00 W DC-input power
supplies.
supplies.
The internal p ower supp lies have individu al power cords an d status LEDs (PS1 an d PS2 on the front
panel). Th ere are also LEDs o n the power supp lies that show status for th e input (Inpu t OK) and o utput
(Output OK) cu rren ts. A power cord is used to con nect the power su pplies to the site AC so urce. There
is a power switch on th e AC-inp ut power supp lies; AC power is present when a power cord is plugged
into a power supply and the switch is set to th e On po sition. DC-inp ut p ower supp lies attach to source
DC using customer-supplied cables.
panel). Th ere are also LEDs o n the power supp lies that show status for th e input (Inpu t OK) and o utput
(Output OK) cu rren ts. A power cord is used to con nect the power su pplies to the site AC so urce. There
is a power switch on th e AC-inp ut power supp lies; AC power is present when a power cord is plugged
into a power supply and the switch is set to th e On po sition. DC-inp ut p ower supp lies attach to source
DC using customer-supplied cables.
The switch starts with only one p ower supply plug ged in, bu t redu ndant failover and load sharin g is not
availab le in this co nfiguration. Cisco recommen ds that you always co nnect both power supplies to
sep arate AC o r DC circuits for o ptimal power reliability.
availab le in this co nfiguration. Cisco recommen ds that you always co nnect both power supplies to
sep arate AC o r DC circuits for o ptimal power reliability.
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