EXFO CableSHARK P3 VF/DSL Cable Qualifier - Manual (Page 132)

VF / DSL Cable Qualifier
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The Longitudinal Balance Test Setup menu has several options that appear at the upper part of the screen
(see the previous illustration). The parameters can be modified to customize a Longitudinal Balance test.
The Longitudinal Balance test setup options are described as follows:
TEST TYPE: LONG BAL NEAR END . This test is a single ended longitudinal balance test
where the resultant is plotted from 26 kHz to 2208 kHz.
TERM
IMPEDANCE: The options are 100 ohms, 135 ohms, and AUTO (older hardware will still show
120 and 150 ohms). For single-ended tests, the AUTO impedance setting is
recommended because it gives better accuracy by measuring the cable and
selecting the most appropriate attenuation.
8.5.2 Running a Longitudinal Balance Test
Use caution when connecting the test set, as telephone cables may have dangerous A.C. or D.C.
voltages on them. The CableSHARK will not run a Longitudinal Balance if the voltage on the line
is greater than 10 volts.
Press the RUN / STOP button on the front of the CableSHARK to initiate the test. Figure 8.5.2A shows an
example of the results obtained from a Longitudinal Balance Test.