Allied Telesis AlliedWare Plus AT-GS980M/52, Руководство по установке, Страница: 84 / 94

Chapter 7: Troubleshooting
84
 Try connecting another network device to the twisted pair port with
a different cable. If the twisted pair port is able to establish a link,
then the problem is with the cable or the other network device.
 Verify that you are using the appropriate category of twisted pair
cable. Refer to “Cable Requirements” on page 22.
 Verify that the port is connected to the correct twisted pair cable.
Note
Twisted pair ports may require five to ten seconds to establish a link.
Problem 4: The LINK/ACT LED is off for an SFP transceiver that is
connected to an active network device.
Solutions: The fiber optic port on 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 to the port on the remote network device.
 Check that the transceiver is fully inserted in the slot.
 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 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 two BiDi (bi-directional) transceivers cannot establish a link, refer
to their data sheets to verify that their transmission and reception
frequencies are opposite to 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 too strong (maximum input power).
Problem 5: The AT-GS980M/52PS Switch is not providing power to any
powered devices or to only a few devices whose power requirements are