| Interface Commands
This command performs cable diagnostics on the specified port to diagnose any
cable faults (short, open, etc.) and report the cable length.
test cable-diagnostics interface interface
unit - Unit identifier. (Range: 1)
port - Port number. (Range: 1-24/48)
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.
This cable test is only accurate for Gigabit Ethernet cables 0 - 250 meters long.
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.
Potential conditions which may be listed by the diagnostics include:
OK: Correctly terminated pair
Open: Open pair, no link partner
Short: Shorted pair
Not Supported: This message is displayed for Gigabit Ethernet ports linked
up at a speed lower than 1000 Mbps.
Impedance mismatch: Terminating impedance is not in the reference
Ports are linked down while running cable diagnostics.
To ensure more accurate measurement of the length to a fault, first disable
power-saving mode (using the
before running cable diagnostics.
– 308 –
command) on the link partner