Specifications

Hardware Reference 43
Software Release 3.0.2
C613-03092-00 REV C
Troubleshooting
This section provides information on how to troubleshoot AT-8900, AT-9900,
and AT-9900s switches to resolve the following basic problems:
■ L/A LED on a port is off
■ Power LED is off
■ Fault LED is on
What to check first ■ Check power cord connections.
■ Check that the power supply voltage is stable.
■ Check that the correct data cables are used and that their connections are
secure.
■ Make sure that other network devices work properly.
■ Use the show install command to check that the latest software release is
loaded. The Software Reference describes how to obtain the latest software
release.
■ If the switch malfunctions, reboot it. Either use a small diameter pin to
operate the recessed Reset button on the switch’s front panel or enter the
restart reboot command. Alternatively, shut down and restart the switch at
either the main power source (AC models) or use the Run/Standby switch
on the PSU (DC models).
L/A LED on a
port is off
If the Link/Activity LED is off, it may indicate the following:
■ a loose data cable
■ the device at the other end of the connection does not work properly or is
turned off
■ the data cable is not wired correctly
■ the network administrator has manually disabled the port through the
software
■ the port’s selected transmission mode does not match that of the attached
device
Follow these suggestions to resolve the problem:
1. Make sure the data cable connections are secure.
2. Make sure the device at the other end of the connection is powered on and
works properly.
3. Check that the data cable is wired correctly.
4. If you can, log in and check the port status. How to log in is described in the
Installation and Safety Guide.
5. If the port is enabled, make sure the transmission speed matches that of the
connected device (autonegotiating, full or half-duplex).
6. If the port is disabled, someone disabled it with the software. Find out why
before you enable it.