Operation Manual

Chapter 6
Structured cabling testing
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Effects of
3 Pairs on 1 Pair
When using Power Sum NEXT, four (4) calculations on each cable end and on each wire pair
combination (pairs 1-2, 3-6 and 4-5 to 7-8 etc.) are performed. A total of eight (8) values is
obtained.
Illustration 1 6.10.1. Power Sum NEXT
NOTE:
The Power Sum NEXT values are usually 2 - 3 dB below the value (= stronger crosstalk)
than with conventional NEXT measurement.
When using Power Sum ACR-F (Power Sum ELFEXT), four (4) calculations on the side of the
Display handset (DH) and on each wire pair combination (pairs 1-2, 3-6 and 4-5 to 7-8 etc.)
are performed. A total of eight (8) values is obtained.
Illustration 2 6.10.1. Power Sum ACR-F (Power Sum ELFEXT)
6.10.1. NEXT Test and ACR-F (Power Sum ELFEXT) Test Error
Crosstalk is usually caused by faulty connections at the cable ends. The lower the measuring
values in dB, the stronger the crosstalk.