Memory
11
Overview of Cisco 3800 Series Routers
OL-5966-01
Memory
Cisco 3800 series routers contain the following types of memory: 
• Main memory consists of ECC DDR SDRAM. It stores the running configuration and routing tables, 
and buffers packets at the network interfaces. Both routers ship with 256 MB of main memory. The 
two DIMM slots can be upgraded with 128-MB, 256-MB, or 512-MB DIMMs to a maximum of 
1024 MB (1 GB). 
• An external CompactFlash memory card stores the Cisco IOS software image. The routers are 
shipped with a 64-MB CompactFlash memory card, which can be upgraded to 128 MB or 256 MB. 
• The routers boot from 4 MB of internal flash memory. This memory cannot be upgraded. 
Power
Table 1 summarizes power options for Cisco 3800 series routers. Both the Cisco 3825 router and the 
Cisco 3845 router support an AC input power supply, an AC input power supply with IP phone power 
output, or a DC input power supply. The Cisco 3825 router has one internal power supply and also 
provides a connector for the optional Cisco Redundant Power System (RPS) external backup power 
source. The Cisco 3845 router supports two internal power supplies and operates in redundant mode both 
are installed. 
Table 1 Cisco 3800 Series Routers Power Options
Router Power Option Input IP Phone Power Output
Cisco 3825 AC input without IP phone power 
output
100–240 VAC, 3 A None
AC input with 24 ports of IP phone 
power output
100–240 VAC, 8 A –48 VDC, 360 W
DC input without IP phone power 
output
24–60 VDC, 12 A None
Cisco Redundant Power System 100 VAC, 10 A
240 VAC, 6 A
If supported by router power supply
Cisco 3845 AC input without IP phone power 
output
100–240 VAC, 5 A None
AC input with 48 ports of IP phone 
power output
100–240 VAC, 9 A –48 VDC, 360 W
DC input without IP phone power 
output
24–60 VDC, 19 A None
Second internal power supply Any option above