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Cisco 1900 Series Hardware Installation
OL-19084-02
Chapter 1 Overview of the Router
Hardware Features
Memory
Cisco 1900 series routers contain the following types of memory:
• DRAM—Stores the running configuration and routing tables and is used for packet buffering by the
network interfaces. Cisco IOS software executes from DRAM memory.
• Boot/NVRAM—Internal flash memory. Stores the bootstrap program (ROM monitor), the
configuration register, and the startup configuration.
• Flash memory—External flash memory (1940 series only). Stores the operating system software
image.
Table 1-3 summarizes the memory options for Cisco 1900 series routers. The default memory numbers
for RAM represent the minimum usable memory. You can install additional RAM in multiples of the
default amount, up to the maximum amount on the Cisco 1940 series ISRs. The Cisco 1905 and Cisco
1921 have factory installed, fixed memory modules and no expansion slots.
Tab l e 1-2 Summary of Cisco 1940 Series Removable and Interchangeable Modules
External Modules (In chassis slots) Internal Modules
CompactFlash 1
1. Only Advanced Capability CompactFlash (CF) purchased from Cisco operate in Cisco 1900 series
ISRs. Legacy CF will not operate in these routers. When legacy CF is inserted, the following error
message appears:
WARNING: Unsupported compact flash detected. Use of this card during
normal operation can impact and severely degrade performance of the
system. Please use supported compact flash cards only.
Enhanced High-Speed WAN
Interface Cards (EHWICs)2
2. HWICs, WICs, and VWICs (data only) are supported.
Internal Service Module (ISM)3
3. Non wireless models only.
2 2 1
Tab l e 1-3 Router Memory Specifications
DRAM 1940 Series 1905 1921
DRAM Type—Unregistered DIMM
(UDIMM)
DIMM sizes—512 MB, 1 GB, 2
GB
DIMM expansion slots—1
Default onboard memory—512
MB non ECC
Maximum memory—2.5 GB
Boot or NVRAM—Internal
16-MB flash memory.
Type—DDR2
DIMM expansion slots—0
Default onboard
memory—2561 MB non ECC
Maximum memory—512 MB2
Boot or NVRAM—Internal 16 MB
flash memory.
1. 256 MB cannot support net boot or warm upgrade functions. Net boot and warm upgrade require 512 MB of memory.
2. 512 MB activation requires memory licensing feature. See the Cisco IOS Software Activation Configuration Guide for details.
Type—DDR2
DIMM expansion slots—0
Default onboard
memory—512 MB non ECC
Maximum memory—512 MB
Boot or NVRAM—Internal 16 MB
flash memory.