17
Cable Diagnostics
Upon booting up the Switch, a
Cable Diagnostics
is used to detect two
problems that may prevent successful connection. This feature operates only
on ports that are connected to 1000Mbps devices. If there a re proble ms on a
port connected to a Gigabit Ethernet device (1000Mbps), try restarting the
Switch and watch the speed (100/ 1000Mbps) LED indicators to determine is
the problem is a fault in the cable or connecting hardware. For ports operating
at 10 or 100Mbps, the LED indicators can be used for less specific
troubleshooting.
The faults detected by the cable diagnostics for 1000Mbps operation are as
follows:
•
Open circu it - a lack of continuity between the pins at each end of the
Ethernet cable or a disconnected cable.
•
Short circu it - t wo or mo re conductors short-circuited.
During the diagnostic, each port is scanned to determine if the Ethernet cable
and connectors is in good working order. Du ring the diagnostic process the
speed LED for each port blinks green in sequential order. This port scan takes
about 3 seconds. If a cable fault is detected, the corresponding port’s speed
LED will light a mber for 5 seconds. The Switch is then reset for norma l
operation. It takes about 2 seconds for the Switch to reset. The entire Cab le
diagnostics process takes about 10 seconds fro m the time the Switch is
powered on.
The table below su mmarizes Cab le diagnostics informat ion.
NOTE:
the cable diagnostics function does not
detect the length of Ethernet cabling. Remember
that the length of cabling between two Ethernet
devic es may not exceed 100 meters (or 300 feet).
