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System Configuration 25
Cable Diagnostics
This section describes:
• "Copper Port Cable Test" on page 25
• "Fiber Port Cable Test" on page 27
NOTE: Cable Diagnostics is supported on SFP/XFP ports but not on the Stacking/CX-4/SFP+/10GbaseT ports.
Copper Port Cable Test
The cable test feature enables you to determine the cable connection status on a selected port. The switch
uses Time Domain Reflectometry (TDR) technology to determine the quality and characteristics of a
copper cable attached to a port.
NOTE: The cable test feature is supported only for copper cable. it is not supported for optical fiber cable.
NOTE: The copper-related commands do not apply to the stacking, 10G BaseT, or CX-4 ports associated with these
plug-in modules.
In privileged exec mode, enter test copper-port tdr unit/port to run the cable test on the
specified port. One of the following statuses are returned:
•
Normal
: The cable is working correctly.
•
Open
: The cable is disconnected or there is a faulty connector.
•
Short
: There is an electrical short in the cable.
•
Cable Test Failed
: The cable status could not be determined. The cable may in fact be working.
The command also returns a cable length estimate if this feature is supported by the PHY for the current
link speed. The length is displayed as the estimated length. Note that if the link is down and a cable is
attached to a 10/100 Ethernet adapter, then the cable status may display as Open or Short because some
Ethernet adapters leave unused wire pairs unterminated or grounded. Unknown is displayed if the cable
length could not be determined.
If the port has an active link while the cable test is run, the link can go down for the duration of the test. The
test may take several seconds to run.
To view cable status information for multiple ports, enter show copper-ports tdr. If the cable test
has not been run on a port, the results indicate that the test has not been performed.