Fluke Networks CertiFiber Pro Users Manual - Manual (Page 249)

Chapter 9: How to Use the OptiFiber Pro OTDR Module
About Launch and Tail Cords
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Caution
To help make sure the tester can find the Tail event
when you do tests on fibers with APC connectors,
use a tail cord that is terminated with a non-APC
connector at the far end.
Note
Do not use hybrid patch cords to connect the
launch or tail cords to the cabling under test. Use
launch and tail cords with the correct connectors
to connect directly to the cabling under test. This
gives the best measurement of the first and last
connectors in the link. Launch and tail cords with
different types of connectors are available from
Fluke Networks.
How To Compensate for Launch and Tail Cords
The launch compensation function lets you specify the lengths of
the launch and tail cords. The OTDR can then remove the losses,
lengths, and attenuation coefficients of the launch and tail cords
from overall OTDR results. It does not remove the losses of the
connections at the launch and tail cords.
Launch compensation also gives a more accurate ORL (optical
return loss) measurement if you entered the correct backscatter
coefficient for the fiber you will test.
Methods of Launch Compensation
The tester has four methods of compensation:
 Launch Only: Does an OTDR test to find the end of the launch
cord.
 Launch + Tail: Does an OTDR test to find the ends of the
launch cord and tail cords.
 Launch + Fiber + Tail: Use this method for links that have
different connectors on the near and far ends of the fiber.