Allied Telesis AT-FS238b/2 - Manual (Page 44)

Troubleshooting
34
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If the twisted pair port is set to Auto-Negotiation, the end-node
connected to the port should also be using Auto-Negotiation. If the
end-node is not using Auto-Negotiation and has a fixed duplex mode
of full-duplex, a duplex mode mismatch will result. To resolve this, you
must disable Auto-Negotiation on the port and adjust the speed and
duplex setting manually using the DIP switches. For further
information on this, refer to “Duplex Mode” on page 12.
❑
If you disabled Auto-Negotiation on the port, check to be sure that the
port is operating at the same speed and duplex mode as the end-node.
❑
If you disabled Auto-Negotiation, the port is configured as MDI-X. A
crossover cable will be required if the port on the end-node is also MDI-
X.
If the LNK LED for the fiber optic port is OFF, do the following:
❑
Verify that the end-node connected to the port is ON and is operating
properly.
❑
Check that the fiber optic cable is securely connected to the fiber optic
port on the bridging converter and on the end-node.
❑
Test the attenuation on the fiber cable to ensure that it does not
exceed acceptable values.
❑
Verify that you are using the appropriate type of fiber optic cable and
that you have not exceeded the maximum operating distance. For
cable types and maximum operating distances, refer to Table 4 on
page 21.
❑
If you connected the fiber optic port to another bridging converter,
verify that the two bridging converters are of the same series and that
there is an “a” unit and a “b” unit. For instance, you cannot connect the
fiber optic ports of two AT-FS238a/1 devices together; nor can you
connect an AT-FS238a/1 unit and an AT-FS238b/2 together. The AT-
FS238a/1 must be teamed with AT-FS238b/1 and the AT-FS238a/2
must be teamed with AT-FS238b/2.
❑
If you connected the fiber optic port to an IEEE 802.3ah-compliant
device, verify that the device is operating at 100 Mbps and that the
operating specifications of its fiber optic port matches that of the fiber
optic port on the bridging converter. For fiber optic port specifications,
refer to “Fiber Optic Port Specifications” on page 39.