Cisco 3800 Series Quick Start Manual page 57

Figure 19
Connecting Routers to Backup Power
The Cisco 3845 router accommodates two hot-swappable power supplies in bays at the front of the
router. A single power supply meets router requirements. The second power supply provides
redundancy, load sharing, and increased router availability. Either power supply can be removed without
affecting router operation. Any combination of two power supplies is permitted.
For instructions for installing a second power supply in a Cisco 3845 router, see the
Upgrading Internal Components in Cisco 3800 Series
The Cisco 3825 router has one internal power supply and provides a connector to an optional
Cisco Redundant Power System (RPS) external backup source.
connection. Use a flat-blade screwdriver to pry off the door over the RPS connector before connecting
the cable. See the
instructions.
Before connecting the RPS to the router, make sure that either the RPS is in standby mode or the RPS
Caution
AC power is disconnected. Connecting the RPS to AC power automatically places the RPS in
active mode.
OL-5970-02
Source A and Source B Wired with Opposite-Polarity Grounds
A- A-
Va Va
+ +
A+ A+
B+ B+
+ +
Vb Vb
B- B-
Cisco RPS-675 Hardware Installation Guide
Routers" section.
Figure 20 and
for complete RPS power connection
Connecting Cables to Cisco 3800 Series Routers
Power Connections
"Installing and
Figure 21 illustrate this
27