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Versiv Series Cabling Certification Product Family
Technical Reference Handbook
414
Fiber Type
Settings IOR
: The tester uses the index of refraction to calculate the
optical length of the fiber. Optical length usually differs
slightly from the length of the fiber jackets in a link. This
occurs because fibers are often curved inside their jackets
and because there are small variations in the IOR of the
fibers.
Each fiber type includes a default value, which is the IOR
specified for the fiber by the manufacturer. To use a
different IOR, make a custom fiber type. See Chapter 19.
Note
If you use a length-based test limit, the IOR value
has an effect on the loss limit that the tester
calculates. See “OTDR Settings for Limits that
Calculate a Loss Limit” on page 415.
Fiber Type
Settings
(continued)
Backscatter
: Backscatter is the backscatter coefficient. This
is a measurement of the quantity of light that the fiber
reflects back to the OTDR when the OTDR uses a 1 ns pulse.
The tester uses this value to calculate the reflectance of
events for OTDR tests and the overall ORL for the link. Each
fiber type includes a default value, which is the backscatter
coefficient specified for the fiber by the manufacturer. To
use a different backscatter value, make a custom fiber
type. See Chapter 19.
Test Limit
Select the correct test limit for the job. Generic limits, such
as
General PON
and
Document PON
, let you do tests when
no industry-standard limit is applicable and you do not
want to make a custom limit. These limits are in the
Miscellaneous
group. To see a different group of limits,
tap
MORE
, then tap the name of a group. To make a
custom test limit, see Chapter 19.
Some test limits use the measured length of the fiber to
calculate a limit for loss. See “OTDR Settings for Limits that
Calculate a Loss Limit” on page 415.
Test Limit
Settings
This item shows only if the selected test limit calculates a
loss limit for each link. For such limits, enter the number of
connectors and splices in the link. See Table 16 on page
415.
Table 15. Settings for HDR OTDR Tests (continued)