Owner's Manual

PHY Diagnostics Commands 271
PHY Diagnostics Commands
test copper-port tdr
The test copper-port tdr privileged EXEC command diagnoses with TDR (Time Domain
Reflectometry) technology the quality and characteristics of a copper cable attached to a port.
The device reports only shorts across the cable pairs. The Virtual Cable Test (VCT) analyzes each
of the MDI pairs in the cable being tested. Typically, in a CAT5 RJ-45 cable, the positive and
negative of each pair are twisted together. The pairs that are twisted together are identifiable: solid
orange and striped orange, solid blue and striped blue, solid green and striped green, solid brown
and striped brown are twisted together. If, for example, MDI[0]+/- pins are connected to pairs 1,2
of the RJ45, which are connected to the orange pair, then MDI[0]+ will be connected to the solid
orange and MDI[0]- will be connected to the striped orange. The short between wires that do not
belong to the same pair will not be reported.
Syntax
test copper-port tdr interface
• interface —A valid Ethernet port.
Default Configuration
This command has no default configuration.
Command Mode
Privileged EXEC mode
User Guidelines
The port can only be tested if cable is connected to both sides.
The port under test should be shut down during the test, unless it is a combo port with an
active fiber port.
NOTE: The maximum disatance VCT can function is 120 meters.
Examples
The following example results in a report on the cable attached to port g3.
Console# test copper-port tdr g3
Cable is open at 100 meters