Allied Telesis CentreCOM GS970M Series Installation Manual page 92

Chapter : Chapter 3: Troubleshooting
82
then the problem is with the cable or the other network device.
Verify that the twisted pair cable does not exceed 100 meters (328

feet).
Verify that you are using the appropriate category of twisted pair

cable. Cable requirements can be found in Table 1, Table 3 and
Table 4.
Note
A 1000BASE connection may require five to ten seconds to
establish a link.
The Link/Activity/Speed LED for an SFP transceiver is off.
Problem 4:
The fiber optic port on the transceiver is unable to establish a
Solutions:
link to a network device. Try the following:
Verify that the network device connected to the fiber optic port is

operating properly.
Verify that the fiber optic cable is securely connected to the port on

the media converter channel and to the port on the remote network
device.
Check that the SFP module is fully inserted in the slot.

Verify that the operating specifications of the fiber optic ports on

the SFP transceiver and the 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.

This is to eliminate the possibility that the port is connected to the
wrong remote network device, such as a powered off device.
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 management device, use its

management firmware to determine whether its 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 (sensitivity) or
too strong (maximum input power).