Cisco 2811 ROUTER 2FE 1NME 4HWIC 2PVDM 2AIM IP BASE WITH A/C POWER SUPPLY Specification Guide

Internal multispeed fans provide chassis cooling, controlled by an onboard temperature sensor.

The Cisco 2801 router has two fans. The Cisco 2801 router with inline power includes two additional 
fans integrated with the inline power supply, for a total of four fans. The Cisco 2801 internal fans operate 
at three different speeds, running at the slower speeds to conserve power and reduce fan noise at ambient 
temperatures below 40

o

C. They operate at the highest speed in ambient temperatures above 40

o

C.

The Cisco 2811 router has three fans that operate at a slower speed to conserve power and reduce fan 
noise at ambient temperatures below 32

o

C. They operate at high speed in ambient temperatures above 

32

o

C. 

The Cisco 2821 and Cisco 2851 routers have three fans that operate at a slower speed to conserve power 
and reduce fan noise at ambient temperatures below 40

o

C. They operate at high speed in ambient 

temperatures above 40

o

C.

An internal real-time clock with battery backup provides the system software with time of day on system 
power up. This allows the system to verify the validity of the certification authority (CA) certificate. In 
the Cisco 2811, Cisco 2821, and Cisco 2851 routers, the clock and battery are permanently installed; the 
battery lasts the life of the router under the operating environmental conditions specified for the router. 
The Cisco 2801 router has a socketed lithium battery. This battery lasts the life of the router under the 
operating environmental conditions specified for the router, and is not field-replaceable.

If the lithium battery in a Cisco 2801 router should fail, the router must be returned to Cisco for repair.

Although the battery is not intended to be field-replaceable, the following warning must be heeded:

There is the danger of explosion if the battery is replaced incorrectly. Replace the battery only with 
the same or equivalent type recommended by the manufacturer. Dispose of used batteries according 
to the manufacturer’s instructions. Statement 1015

This section contains views of the front and rear panels of the Cisco 2800 series routers, showing 
locations of the power and signal interfaces, module slots, status indicators, and chassis identification 
labels.

 shows the front panel of a Cisco 2801 router. 

 shows the back panel.