xStack® DGS-3420 Series Layer 2 Managed Stackable Gigabit Switch CLI Reference Guide
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Chapter 13
Cable Diagnostics
Commands
cable_diag ports [<portlist> | all]
13-1 cable_diag ports
Description
This command is used to test copper cabling.
For 10/100Based-TX link speed RJ45 cables, two pairs of cables will be diagnosed.
For 1000Base-T link speed RJ45 cables, four pairs of cables will be diagnosed.
The type of cable errors can be open, short, or crosstalk.
• Open means that the cable in the error pair does not have a connection at the specified
position.
• Short means that the cables in the error pair has a short problem at the specified position.
• Crosstalk means that the cable in the error pair has a crosstalk problem at the specified
position.
For Fast Ethernet ports:
1. Where the link partner is powered on with no errors and the link is up, this command
cannot detect the cable length.
2. Where the link partner is powered on with errors, this command can detect whether the
error is open, short, or crosstalk. In this case this command can also detect the distance of the
error.
3. Where the link partner is powered down with no errors and the link is down, this command
cannot detect the cable length.
4. When the link partner is powered down with errors, this command can detect whether the
error is open, short, or crosstalk. In this case this command can also detect the distance of the
error.
5. When there is no link partner with no errors and the link is up, this command can detect the
cable length.
6. When there is no link partner with errors, this command can detect whether the error is open,
short, or crosstalk. In this case this command can also detect the distance of the error.
For Gigabit Ethernet ports: