Sfp Ports - Allied Telesis x320 Series Installation Manual

SFP Ports

Problem: The LINK/ACT LED is off for an SFP port with a transceiver that
is connected to an active network device.
Solutions: The transceiver is unable to establish a link to a network
device. Try the following:
Verify that the remote network device is operating properly.

Verify that the fiber optic cable is securely connected to the port on

the transceiver and the remote network device.
Check that the transceiver is fully inserted in the port.

Verify that the operating specifications of the fiber optic ports on

the transceiver and remote network device are compatible.
Verify that the correct type of fiber optic cabling is being used.

Verify that the port is connected to the correct fiber optic cable.

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 with the other network device.
Use the switch's management software to verify that the port is

enabled.
If the remote network device is a managed device, use its

management firmware to determine whether its port is enabled.
If the problem is with two BiDi (bi-directional) transceivers, refer to

their data sheets to verify that their transmission and reception
frequencies are opposite each other. For instance, a BiDi
transceiver that transmits and receives at 1310nm and 1550nm,
respectively, has to be connected to a transceiver that transmits
and receives at 1550nm and 1310nm, respectively. Two BiDi
transceivers cannot establish a link if they transmit and receive at
the same frequencies.
Test the attenuation of both directions on the fiber optic cable with

a fiber optic tester to determine whether the optical signal is too
weak (sensitivity) or strong (maximum input power).
x320 Series Installation Guide
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