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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Chapter 6<br />
Structured cabling testing<br />
Illustration 6.9. NEXT, ACR-F (ELFEXT) and Power Sum<br />
The NEXT test determines interfering effects (crosstalk) of a transmitting wire pair on the<br />
adjacent wire pair in the same cable. NEXT is measured on Display handset (DH) and Remote<br />
handset (RH).<br />
1<br />
2<br />
3<br />
6<br />
4<br />
5<br />
7<br />
8<br />
Effect of<br />
Adjacent Pair<br />
‣ FEXT test and NEXT measurement are similar; the only difference is that in FEXT test the<br />
transmissions emanate from Remote handset (RH) and that crosstalk is determined at<br />
Display handset (DH).<br />
‣ NEXT measurements are performed on each cable end and for all wire pair combinations<br />
(pair 1-2 to 3-6 etc.). Thus, a total of 12 measurements is performed.<br />
‣ ACR-F (ELFEXT) measurements take place with the Display handset (DH) and the Remote<br />
handset (RH) on both cable ends and for all possible wire pair combinations (1-2 to 3-6,<br />
3-6 to 1-2, 1-2 etc.). This results in a total of 12 measurements.<br />
6.10. Power Sum NEXT, Power Sum ACR-F (ELFEXT)<br />
Power Sum-Tests determine the crosstalk effects of three transmitting wire pairs on the<br />
fourth wire pair in the same cable.<br />
2<br />
1<br />
6<br />
3<br />
5<br />
4<br />
8<br />
7<br />
62
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