EXFO FTB-635 Wideband Copper and DSL Test Module - Manual (Page 169)

Multimeter Tests
Copper and xDSL Tests 161
Balance Test
Balance Test
The VF Longitudinal Balance test allows you to check that the pair balance
is sufficient to mitigate common-mode noise. The test is a measurement of
how much the T/A leg is like the R/B leg in electrical characteristics,
measured by how much noise the line can mitigate (in dB). It is an overall
health indicator and a quick way to tell if the line is in good condition. The
better the longitudinal balance of the cable pair, the higher the dB reading.
Active
The Active function applies its own signal to take a balance measurement,
displaying and updating results in real time, until you stop the test. The last
valid results then remain displayed. The page also displays the pass/fail
status and Balance value.
To access Active page:
1. From the Copper main menu Test Groups, select Signal test
.
2. From the Tests menu, select Balance test to start the test.
By default, the Active page opens.