Chapter 11
| Interface Commands
Cable Diagnostics
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DDM Thresholds
Transceiver-monitor : Disabled
Transceiver-threshold-auto : Enabled
Low Alarm Low Warning High Warning High Alarm
----------- ------------ ------------ ------------ ------------
Temperature(Celsius) -123.00 0.00 70.00 75.00
Voltage(Volts) 3.10 3.15 3.45 3.50
Current(mA) 6.00 7.00 90.00 100.00
TxPower(dBm) -12.00 -11.50 -9.50 -9.00
RxPower(dBm) -21.50 -21.00 -3.50 -3.00
Console#
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 dsp interface
interface
interface
ethernet
unit/port
unit - Unit identifier. (Range: 1)
port - Port number. (Range: 1-8/24)
Command Mode
Privileged Exec
Command Usage
â—†
Cable diagnostics are performed using Digital Signal Processing (DSP) test
method when the port link-up speed is 1 Gbps. DSP analyses the cable by
sending a pulsed signal into the cable, and then examining the reflection of
that pulse. If the port link-up speed is not 1 Gbps, then Time Domain
Reflectometry (TDR) test method is used. TDR also detects a cable fault by
sending a signal through the cable and reading the signal that is reflected back.
However, note that TDR can only determine if a link is valid or faulty.
â—†
This cable test is only accurate for Ethernet cables 7 - 100 meters long.
â—†
The test takes approximately 5 seconds. Use the show cable-diagnostics
command to display the results of the test, including common cable failures, as
well as the status and approximate length of each cable pair.
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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