Allied Telesis AT-PC2002/POE - Manual (Page 56)

Chapter 3: Troubleshooting
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❒
Verify that the fiber optic cable is securely connected to the port on the
media converter and to the port on the remote network device.
❒
Verify that the network device connected to the fiber optic port is
powered on and is operating properly.
❒
Verify that the operating specifications of the fiber optic ports on the
SFP module and on the remote network device are compatible. The
operating specifications for the SFP module can be found in the
module’s instructions.
❒
Check that DIP switch 4 is set correctly for the SFP module.
❒
Verify that the correct type of fiber optic cabling is being used and that
the maximum operating distance has not been exceeded.
❒
Try connecting another network device to the fiber optic port using a
different cable. If the port is able to establish a link, then the problem is
with the cable or the other network device.
❒
If the remote network device is a managed device, use its
management firmware to verify that the fiber optic port is enabled.
❒
Test the attenuation on the fiber optic cable with a fiber optic tester to
determine whether the optical signal is too weak or too strong. The
specifications of the fiber optic port on the SFP module can be found in
the module’s instructions.
Problem 4: One of the Link LEDs is blinking and the other Link LED is off.
Solutions: The unit is in the Smart MissingLink mode and the port whose
Link LED is off is unable to form a link to its network device. Change the
unit to the Link Test mode and go to Problem 2 for the twisted pair port or
to Problem 3 for the fiber optic port for suggestions on how to resolve the
problem.
Problem 5: The Link LEDs for the two ports are on but the network
devices are not forwarding traffic to each other through the media
converter.
Solutions: Try the following:
❒
If the network devices are managed devices, use their management
firmware to determine whether they are configured and operating
properly.
❒
If one of the network devices is a switch that is using a spanning tree
protocol, use its management firmware to determine the state of the
port that is connected to the media converter. The port may have been
placed in the blocking mode by the switch if it was determined to be
part of a redundant path.