Fluke DSP-100 User Manual page 123

Basic Cable Testing
7
Crosstalk and Near-End Crosstalk (NEXT)
The scale of the vertical scale increases logarithmically. The scale units are
arbitrary. A level of 50 represents a crosstalk magnitude that is close to causing a
cable failure. The level of 100 is approximately 20 times greater than the level of
50. A level of 100 represents an extremely high level of crosstalk that is typically
due to split pairs. Cables or other hardware that cause crosstalk levels of 100 or
above are considered unusable. Crosstalk levels near 0 are considered to be
inconsequential.
The TDX plot from a cable that failed a NEXT test may show one or more peaks
of crosstalk greater than a level of 50. A failure can also be caused by a crosstalk
level less than 50 if the level is sustained over a substantial distance of the cable.
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