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Loss is more than expected or is reported as "Too High".
•
The fibers are connected to the wrong ports on the tester, or are swapped at one end of the cabling.
•
A reference test cord is broken.
•
There is one or more dirty, damaged, misaligned, or unseated connections in the cabling. Check all connections and
clean all fiber endfaces, then retest. Or use the OTDR locate bad connections.
Tip: An OTDR cannot measure the loss of the first and last connections in the cabling unless you use a launch and receive
fiber during the OTDR test. If the first or last connection is bad, and you do not use launch and receive fibers, the
OTDR test may pass because it does include the loss of the bad connection. See "About Launch and Receive Fibers"
in Chapter 3 for details.
•
The number of adapters or splices on the Cable tab in Setup is too low (for limits that use a calculated loss value).
•
The wrong fiber type is selected on the Cable tab in Setup.
•
The reference is incorrect. Set the reference again using the same reference test cords to be used for testing.
•
A reference test cord or fiber segment has the wrong core size. If the reference test cords are the correct type, use the
OTDR to look for mismatched fiber in the cabling.
•
The cabling has a bad fusion or mechanical splice or a sharp bend. Use the OTDR to locate these faults.
Disconnect the source before connecting the OTDR to the cabling. Live sources can
damage the OTDR's receiver.
Table 7-10. Diagnosing Loss/Length Test Failures
W
Caution
Using the Loss/Length Option
Diagnosing Loss/Length Test Failures
7
-continued-
7-37
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