C
HAPTER
26
| Interface Commands
Cable Diagnostics
– 990 –
Cable Diagnostics
test cable-
diagnostics
This command performs cable diagnostics on the specified port to diagnose
any cable faults (short, open, etc.) and report the cable length.
SYNTAX
test cable-diagnostics interface interface
interface
ethernet unit/port
unit - Unit identifier. (Range: 1)
port - Port number. (Range: 1-28/52)
COMMAND MODE
Privileged Exec
COMMAND USAGE
â—† Cable diagnostics are performed using Digital Signal Processing (DSP)
test methods. DSP analyses the cable by sending a pulsed signal into
the cable, and then examining the reflection of that pulse.
â—† This cable test is only accurate for cables 7 - 100 meters long.
â—† The test takes approximately 5 seconds. The switch displays the results
of the test immediately upon completion, including common cable
failures, as well as the status and approximate length of each cable
pair.
â—† Potential conditions which may be listed by the diagnostics include:
â–
OK: Correctly terminated pair
â–
Open: Open pair, no link partner
â–
Short: Shorted pair
â–
Not Supported: This message is displayed for any Fast Ethernet
ports that are linked up, or for any Gigabit Ethernet ports linked up
at a speed lower than 1000 Mbps.
â–
Impedance mismatch: Terminating impedance is not in the
reference range.
â—† Ports are linked down while running cable diagnostics.
â—† To ensure more accurate measurement of the length to a fault, first
disable power-saving mode (using the no power-save command) on the
link partner before running cable diagnostics.
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