LanTEK® II Series Manual - Ideal Industries Inc.
LanTEK® II Series Manual - Ideal Industries Inc.
LanTEK® II Series Manual - Ideal Industries Inc.
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6.7. Length Test<br />
Chapter 6<br />
Structured cabling testing<br />
This test determines the length of wire pairs to ensure that the recommended limits for the<br />
selected cable are complied with. Depending on the measurement unit selected in<br />
"Preferences", the length is indicated in Foot or Meter.<br />
6.7.1. Length Test Error<br />
Illustration 6.7. Length Test<br />
Minor length differences can occur between the wire pairs of a cable due to small NVP<br />
differences, as well as length differences caused by transposition. A failure exists if the<br />
electronically measured cable length deviates too much from the actual length.<br />
6.8. Resistance Test<br />
This test determines the loop resistance of the individual wire pairs. This ensures that the<br />
total loop resistance does not exceed the recommended limits. For each wire pair, the results<br />
are displayed as resistance value in ohm, together with the reference limit for the cable type.<br />
6.8.1. Resistance Test Error<br />
Illustration 6.8. Resistance Test<br />
All four wire pairs of a transmission line within the network should have approximately the<br />
same resistance. If the resistance value of a wire pair exceeds the limit, the test is considered<br />
failed.<br />
6.9. NEXT, ACR-F (ELFEXT) and Power Sum<br />
In an Autotest, crosstalk at the near and far end of the cable is measured with NEXT (Near<br />
End Cross Talk) and ACR-F (ELFEXT) tests. High crosstalk levels can result in frequent<br />
recurrences, damage to data and other interferences that impair transmission rate.<br />
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