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Software Configuration Guide—Release 12.2(25)SG
OL-7659-03
Chapter 5 Checking Port Status and Connectivity
Checking Cable Status Using TDR
Overview
With TDR, you can check the status of copper cables on the 48-port 10/100/1000 BASE-T modules for
the Catalyst 4500 series switch (WS-X4548-GB-RJ45, WS-X4548-GB-RJ45V, WS-X4524-GB-RJ45V,
WS-X4013+TS, WS-C4948, and WS-C4948-10GE). TDR detects a cable fault by sending a signal
through the cable and reading the signal that is reflected back. All or part of the signal can be reflected
back either by cable defects or by the end of the cable.
Note There are four pairs of standard category 5 cable. Each pair can assume one of the following states: open
(not connected), broken, shorted, or terminated. The TDR test detects all four states and displays the first
three as “Fault” conditions, and displays the fourth as “Terminated.” Although the CLI output is shown,
the cable length is shown only if the state is “Faulty.”
Running the TDR Test
To start the TDR test, perform this task in privileged mode:
This example shows how to start the TDR test on port 1 on module 2:
Switch# test cable-diagnostics tdr int gi2/1
Switch#
This example shows the message that displays when the TDR test is not supported on a module:
Switch# test cable-diagnostics tdr int gi2/1
00:03:15:%C4K_IOSDIAGMAN-4-TESTNOTSUPPORTEDONMODULE: Online cable
diag tdr test is not supported on this module
Switch#
This example shows how to display TDR test results for a port:
Switch# show cable-diagnostics tdr interface gi4/13
Interface Speed Local pair Cable length Remote channel Status
Gi4/13 0Mbps 1-2 102 +-2m Unknown Fault
3-6 100 +-2m Unknown Fault
4-5 102 +-2m Unknown Fault
7-8 102 +-2m Unknown Fault
Note This command will be deprecated in future releases of Cisco IOS software. Please use the diagnostic
start and the show diagnostic result commands to run the TDR test and display the test results.
Note TDR is a port test; the port can not handle traffic for the duration of the test (generally, 1 minute).
Command Purpose
Step 1
Switch# test cable-diagnostics tdr
{
interface
{
interface interface-number
}}
Start the TDR test.
Step 2
Switch# show cable-diagnostics tdr
{
interface
{
interface interface-number
}}
Show the TDR test counter information.