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A P P E N D I X
Cisco 4000 Series Virtual Configuration Register B-1
Cisco 4000 Series Virtual
Configuration Register
B
This appendix describes the Cisco 4000 series virtual configuration register, the factory default
settings, and the procedures for changing those settings.
Virtual Configuration Register Settings
The Cisco 4000 series has a 16-bit virtual register, which is written into the nonvolatile random
access memory (NVRAM). Use the processor configuration register information contained in this
appendix to do the following:
•
Set and display the configuration register value.
•
Force the system into the bootstrap program.
•
Select a boot source and default boot filename.
•
Enable or disable the Break function.
•
Control broadcast addresses.
•
Set the console terminal baud rate.
•
Load operating software from ROM.
•
Enable booting from a Trivial File Transfer Protocol (TFTP) server.
Table B-1 lists the meaning of each of the virtual configuration memory bits.
Table B-1
Virtual Configuration Bit Meanings
Bit No.
Hex
Meaning
00–03
0x0000–0x000F
Boot field (see Table B-2)
06
0x0040
Causes system software to ignore nonvolatile memory contents
07
0x0080
OEM bit enabled
08
0x0100
Break disabled
10
0x0400
IP broadcast with all zeros
11–12
0x0800–0x1000
Console line speed
13
0x2000
Boots default ROM software if network boot fails
14
0x4000
IP broadcasts do not have net numbers
15
0x8000
Enables diagnostic messages and ignores NVRAM contents
Summary of Contents for Explorer 4700
Page 18: ...xviii Cisco 4000 Series Hardware Installation and Maintenance Document Conventions ...
Page 116: ...Cable Specifications 2 Book Title 78 xxxxx xx ...
Page 132: ...D 6 Cisco 4000 Series Hardware Installation and Maintenance Entering the ROM Monitor Program ...
Page 134: ...E 2 Cisco 4000 Series Hardware Installation and Maintenance For United Kingdom Use Only ...
Page 136: ...F 2 Cisco 4000 Series Hardware Installation and Maintenance For European Community Use Only ...