Specifications

42 AT-9900 Series Switch
C613-03084-00 REV A
Troubleshooting
This section provides information on how to detect and resolve problems with
AT-9900 Series switches.
Other sources of useful troubleshooting information are:
■ http:// www.alliedtelesyn.co.nz/support
■ The AT-9900 Series Software Reference.
Check these first
■ Check the 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. How to obtain the latest software release is described in the
AT-9900 Series Software Reference.
■ 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
command restart reboot. Alternatively, shut down and restart the switch at
either the mains power source (AC models) or use the Run/Standby
switch on the PSU (DC models).
Link/Activity LED on any port is off
This can indicate:
■ 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.
Perform these steps in sequence:
1. Make sure the data cable connections are secure.
2. Make sure the device at the other end of the connection is switched 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
“How to log in” on page 14
5. If the port is enabled, make sure the transmission speed matches that of the
connected device (auto-negotiating, full or half-duplex).