Real-Time Clock - Cisco 2900 series Installation Manual

Chapter 1 Overview of the Routers
Figure 1-22
Figure 1-23

Real-Time Clock

Upon system power up, the internal real-time clock with battery backup provides the system software
with the time of day. This allows the system to verify the validity of the certification authority (CA)
certificate. The Cisco 2900 and Cisco 3900 series routers have a lithium battery. This battery lasts for
the life time of the router under the operating environmental conditions specified for the router and is
not field-replaceable.
Note If the lithium battery in a Cisco 2900 or Cisco 3900 series ISR 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:
Warning 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
OL-18712-02
Cisco 3900 Series (Non NEBS) Router Airflow
SY S
AC T SY S
AU X
PW R1 SY S
AU X
PW R1
PW R2
PW R2
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Cisco 3900 Series NEBS Router Airflow
SY S
AC T SY S
AU X
PW R1 SY S
PW R1 AU X
PW R2
PW R2
Ci sc o 39
Cisco 2900 Series and 3900 Series Hardware Installation Guide
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Hardware Features
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