Installation guide

Cisco 4000 Series Virtual Configuration Register D-7
Virtual Configuration Register Settings
Bit 8 controls the console Break key. Setting bit 8 (the factory default) causes the processor
to ignore the console Break key. Clearing bit 8 causes the processor to interpret Break as a
command to force the system into the bootstrap monitor, halting normal operation. A Break
can be sent in the first 60 seconds while the system reboots, regardless of the configuration
settings.
Bit 10 controls the host portion of the Internet broadcast address. Setting bit 10 causes the
processor to use all zeros; clearing bit 10 (the factory default) causes the processor to use
all ones. Bit 10 interacts with bit 14, which controls the network and subnet portions of the
broadcast address. Table D-4 shows the combined effect of bits 10 and 14.
Table D-4 Configuration Register Settings for Broadcast Address Destination
Bit 13 determines the server response to a bootload failure. Setting bit 13 causes the server
to load operating software from ROM after five unsuccessful attempts to load a boot file
from the network. Clearing bit 13 causes the server to continue indefinitely to attempt
loading a boot file from the network. By factory default, bit 13 is cleared to 0.
Bits 11 and 12 in the configuration register determine the baud rate of the console terminal.
Table D-5 shows the bit settings for the four available baud rates. (The factory-default baud
rate is 9600.)
Bit 14 Bit 10 Address (<net> <host>)
Off Off <ones> <ones>
Off On <zeros> <zeros>
On On <net> <zeros>
On Off <net> <ones>