Web Management Guide-R07

Table Of Contents
Chapter 4
| Interface Configuration
Port Configuration
– 122 –
Performing Cable
Diagnostics
Use the Interface > Port > Cable Test page to test the cable attached to a port. The
cable test will check for any cable faults (short, open, etc.). If a fault is found, the
switch reports the length to the fault. Otherwise, it reports the cable length. It can
be used to determine the quality of the cable, connectors, and terminations.
Problems such as opens, shorts, and cable impedance mismatch can be diagnosed
with this test.
Command Usage
Cable diagnostics are performed using Time Domain Reflectometry (TDR).
TDR detects a cable fault by sending a signal through the cable and reading the
signal that is reflected back. TDR can only determine if a link is valid or faulty.
Cable diagnostics can only be performed on twisted-pair media.
This cable test is only accurate for Gigabit Ethernet cables 7 - 100 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 to a fault.
Potential conditions which may be listed by the diagnostics include those listed
below. Note that TDR testing can only show Test failed or OK.
Test failed
OK: Correctly terminated pair
Open: Open pair, no link partner
Short: Shorted pair
Impedance mismatch: Terminating impedance is not in the reference
range.
No cable
Not tested
Not Supported: This message is displayed for any Gigabit Ethernet ports
linked up at a speed lower than 1000 Mbps, or for any 10G Ethernet ports.
Unknown – Unknown error
Ports are linked down while running cable diagnostics.
Parameters
These parameters are displayed:
Port – Switch port identifier.
Type – Displays media type. (GE – Gigabit Ethernet, Other – SFP)
Link Status – Shows if the port link is up or down.