Allied Telesis AT-8516F/SC Installation Manual page 74

Troubleshooting
Make sure that you are using the appropriate type of fiber optic
cable and that the cable length does not exceed the allowed
maximum distance. For an AT-8516F Series switch, refer to
Planning the Installation on page 48. For an optional GBIC or SPF
module, or other expansion module, refer to the Installation
Guide shipped with the module.
Use a fiber optic tester to test the attenuation on the cable to
determine if the strength of the fiber optic signal falls below
acceptable limits. (For fiber optic port specifications for an
AT-8516F Series Switch, refer to AT-8516F/SC Fiber Optic Port
Specifications on page 86. For an optional GBIC or SPF module, or
other expansion module, refer to the Installation Guide shipped
with the module.
Check that the operating specifications (for instance, wavelength
and maximum operating distance) of the fiber optic port on the
remote end node are compatible with the fiber optic port on the
switch. For example, you cannot connect a fiber optic port with a
maximum distance of 40 kilometers (24.8 miles) and an operating
wavelength of 1550 nm to a remote fiber optic port with an
maximum distance of only 2 kilometers (1.24 miles) and a
wavelength of 1310 nm.
Check to be sure that the fiber optic ports on the switch and on
the end node are operating at the same speed and duplex mode.
AT-8550GB and AT-8550SP switches only
module or SFP module is completely inserted into the expansion
slot on the front of the switch.
Note
A 1000Base connection can take from five to ten seconds to
establish a link.
If you attached a powered device to a port on an AT-8524POE, the PoE
LED for the port should be green. (Remember to use the Mode Select
button to toggle the Mode LEDs to the PoE state.) If the device is not
receiving power or the PoE LED is flashing amber, steady amber, or is
OFF, do the following:
Check to be sure that the powered device is designed to receive
power over pins 1, 2, 3, and 6 on the RJ-45 port. This can be
verified by reviewing the device's documentation or datasheet.
Check that the device's power requirements do not exceed 15.4
W. This can be verified by reviewing the device's documentation
or datasheet.
Verify that the GBIC
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