Operation Manual

Using the OTDR Module

Setting Up for OTDR Testing

7-19

Table 7-1.

Setting Description

When Fiber Characteristics is set to User Defined, the n and Backscatter values can be edited by

the user. When the Fiber Characteristics is set to Default, the tester uses the values defined in

the current Fiber Type.

The n value is the index of refraction. Index of refraction is used to calculate length. The default

n values defined in the fiber types are suitable for most applications. Minor differences

between the default n and a fiber's actual n usually do not make enough difference in length

to fail a fiber.

Increasing n decreases measured length.

Backscatter is the backs

catter coefficient, which indicates the amount of light the fiber reflects

back to the OTDR (using a 1 ns pulse). This value is used to calculate event reflectance for OTDR

tests.

Enter the backscatter coefficient of the fibe

r under test, if known. This value is specified by

many fiber manufacturers.

OTDR Test Settings (cont.)

-continued-

Fiber Characteristics

Backscatter