Operation Manual

Chapter 6
Structured cabling testing
66
6.14.1. Delay and Skew Test Error
The delay and skew measurements usually result in slightly different values for the individual
wire pairs of a cable. However, a large difference indicates a cable fault or a damaged wire
pair.
6.15. Capacitance Test
This test determines the mutual capacitance between the two conductors of each wire pair, to
ensure that the capacitance of the corresponding cable type has not been impaired by the
installation.
 The capacitance test of the analysis mode indicates the overall capacitance in Nanofarad
(nF).
 The Autotest measures the overall capacitance in Picofarad (pF) per meter or foot.
Illustration 6.15. Capacitance Test
6.15.1. Capacitance Test Error
The higher the capacitance, the higher the error rate. Due to transport and installation of the
cable, minor changes in capacitance are normal. Connectors and patch cords also influence
capacitance values.
6.16. ACR-N (ACR) Test and Power Sum ACR-N (Power Sum ACR) Test
The ACR-N (ACR) test determines the loss-crosstalk distance by means of a mathematical
comparison (difference calculation) of the loss and NEXT test results. The differences between
the measuring values of a wire pair indicate whether transmission interferences are likely to
occur in the respective wire pair.
The ACR-N (ACR) measurement is calculated from pair to pair. Power Sum ACR-N (Power
Sum ACR) measurement is calculated by summation of NEXT values between a selected wire
pair and three other wire pairs of the same cable.