3Com Switch 7750 Series
Command Reference Guide — Basic Port Commands Chapter 1 Port Basic Configuration Commands
1-33
Description
Use the virtual-cable-test command to enable the system to test the cable connected
to a specific port and to display the results. The system can test these attributes of the
cable:
z Cable status, including normal, abnormal, abnormal-open, abnormal-short and
failure
z Cable length
Note:
z If the cable is in normal state, the displayed information is “-”.
z If the cable is in any other state, the displayed length value is the length from the
port to the faulty point.
z Pair impedance mismatch
z Pair skew
z Pair swap
z Pair polarity
z Insertion loss
z Return loss
z Near-end crosstalk
By default, the system does not test the cable connected to the Ethernet port.
Note:
z The combo port does not support the virtual-cable-test command.
z The error for cable length tested through the virtual-cable-test command is ±5m.
Example
# Enable the system to test the cable connected to Ethernet1/0/1.
<3Com> system-view
System View: return to User View with Ctrl+Z.
[3Com] interface Ethernet1/0/1
[3Com-Ethernet0/1] virtual-cable-test
Cable status: abnormal(open), 7 metres
Pair Impedance mismatch: yes
Pair skew: 4294967294 ns
Pair swap: swap