Allied Telesis AT-8088/xx (MT and SC) - Manual (Page 76)

Troubleshooting
76
Use a fiber optic tester to test the attenuation on the cable to
determine if the strength of the fiber optic signal falls below
acceptable limits. (For fiber optic port specifications for an
AT-8000 Series Switch, refer to
AT-8016F/xx, AT-8026FC, and AT-
8088/xx Fiber Optic Port Specifications on page 92. For port
specifications for a GBIC module, refer to the GBIC Installation
Guide. For an optional fiber optic expansion module, refer to the
Expansion Module Installation Guide.)
Check that the operating specifications (for instance, wavelength
and maximum operating distance) of the fiber optic port on the
remote end-node are compatible with the fiber optic port on the
switch. For example, you cannot connect a fiber optic port with a
maximum distance of 40 kilometers (24.8 miles) and an operating
wavelength of 1550 nm to a remote fiber optic port with an
maximum distance of only 2 kilometers (1.24 miles) and a
wavelength of 1310 nm.
Check to be sure that the fiber optic ports on the switch and on
the end-node are operating at the same speed and duplex mode.
AT-8024GB switch only — Verify that the GBIC module is
completely inserted into the GBIC expansion slot on the front of
the switch.
Note
A 1000Base connection can take from five to ten seconds for the
link to be established.
If the FAULT LED is blinking, no action is required. A blinking FAULT LED
could indicate that a new version of the management software is being
downloaded to the switch or that the switch’s configuration is being
changed, such as with the creation of a new VLAN. The LED will stop
blinking once the switch has completed the download or its
reconfiguration.
If the FAULT LED is constantly ON, a problem has occurred in the switch.
Do the following:
Reset the switch using the Reset button on the back panel of the
switch.
If the FAULT LED remains ON after you have reset the switch,
power OFF the switch by disconnecting the power cord, wait a
few moments, and then reconnect the power cord.