Chapter 7
Cable Testing Fundamentals
7-14
The FEXT test is similar to the NEXT test except that the traffic is generated at
the RH and crosstalk is measured at the DH.
• NEXT measurements are made at each end of the cable for all pair
combinations (pair 1-2 vs. 3-6, etc.), yielding a total of twelve measurements.
• ELFEXT measurements are made with the DH and RH for all possible pair
combinations (1-2 vs. 3-6, 3-6 vs. 1-2, 1-2 etc.) at both ends yielding a total
of twenty-four measurements.
Power Sum NEXT and Power Sum ELFEXT
Power Sum tests measure the crosstalk effects of three transmitting pairs on the
fourth pair in the same cable sheath.
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