Installing
and
Configuring
Processor
Modules
CRC
is
an
error-checking
technique
that
uses
calculated
numeric
value
to
detect
errors
in
transmitted
data
Because
32-bit
CRC
transmits
longer
data
streams
at faster
rates
it
provides
better
ongoing
error
detection
with
less
retransmits
However
both
the sender
and
the
receiver
must
use
the
same
setting
The
default
for
all serial
interfaces
is
for
16-bit
CRC
To
enable
32-bit
CRC
on
an
interface
specify
the
slot
and
port
address
of the interface
followed
by
the
command
crc32
In the
example
that
follows
the
first
serial
port
on
an
FSIP
in interface
processor
slot
is
configured
for
32-bit
CRC
Router
configure
terminal
Enter
configuration
commands
one
per
line
End
with
CNTL/Z
Routerconfig
interface
aerial
2/0
Router
config-if
crc32
Router
configif
Router
To
disable
32-bit
mode
and
return
to
the default
16-bit
setting
on
specific
interface
specify
the
slot
and
port address
of the interface
and
use
the
no
crc32
command
For
brief overview
of
CRCs
refer
to
the section
Cyclic Redundancy
Checks
in the chapter
Preparing
for
Installation
For
complete
command
descriptions
and
instructions
refer
to
the related
software
documentation
Configuring
4-Bit
Cyclic
Redundancy
Check
The
E1-G.703/G.704
interface
supports
4-bit
CRC
in
framed
mode
only
CRC-4
is
not enabled
by
default
To
enable
CRC-4
on
the
E1-G.703/G.704
interface
specify
the
slot
and
port
address
of the
interface
followed
by
the crc4
command
In the
example
that
follows
the top port
on
an
FSIP
in
interface
processor
slot
is
configured
for
CRC
Router
configure
terminal
Enter
configuration
commands
one
per
line
End
with
CNTL/Z
Routerconfig4
interface
aerial
3/0
Router
config-if
crc4
Routerconfig-if
Router44
To
disable
CRC-4
and
return
to
the default
of
no
CRC
error
checking
specify
the
slot
and
port
address
and
use the
no
crc4
command
For
complete
command
descriptions
and
instructions
refer
to
the related
software
documentation
Replacing
Serial
Port
Adapter Cables
The
port
adapter
cable
connected
to
each
FSIP
port determines
the
electrical
interface
type
and
mode
of the port
The
FSIP
ports
are not
configured
for
either
DTB
or
DCE
mode
by
default
When
there
is
no
cable
attached
to
port
the software
identifies
the port
as
Universal
Cable
Unattached
rather
than
either
DTE
or
DCE
interface
When
cable
is
attached
the port recognizes
the
mode
and
automatically
uses
the clock
signal
from
the appropriate
source
external
for
DTB
or
internal
for
DCE
Although you do
not
have
to
configure
clock
source
for the ports
you
do
have
to
define
the clock
speed
the
first
time
you
configure
port
as
DCE
interface
Because
the ports automatically
use the
appropriate
clock
source
for the type
mode
of cable
it
detects
you
can
configure
clock
rate
for
DCE
interface
and
later
replace
the
DCE
cable
with
DTE
cable
the
FSIP
will
ignore
the
internal
clock
rate
unless
it
detects
that
DCE
cable
is
attached
This
configuration
allows
you
to
perform
loopback
test
on
serial
port
without
port
adapter
cable
attached
Maintaining
the
Router
5-41
Summary of Contents for 7513 Series
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Page 11: ...Cisco 7513 Hardware Installation and Maintenance ...
Page 121: ...Site Log 2 56 Cisco 7513 Hardware Installation and Maintenance ...
Page 162: ...Troubleshooting the Processor Subsystem 4 10 Cisco 7513 Hardware Installation and Maintenance ...
Page 266: ...Interface Processor LEDs B 16 Cisco 7513 Hardware Installation and Maintenance ...
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