ProsKit 15-AT002, Руководство пользователя

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purposely mis-wring, with their Receive and
Transmit wires cross over. The 4 in 1 will test
this as a bad cable, but it may work just fine
as Crossover cable.
6.2 The 4 in 1 says my cable is good, but it
does not work on my LAN:
Many cable testers like the 4 in 1 only
perform continuity style tests (open, short,
crossed, etc). Ethernet LAN cables are
constructed in a special way. The 8 wires
inside are grouped into 4 pairs of 2 way. The
8 wires inside are grouped into 4 pairs of 2
wires each. Not only must the 8 wires
connect from end to end of the cable, the
pairs in the cable must connect to specific
pins of RJ-45 plugs on to the ends of cable
ignoring the pairing (as described in EIA/TIA
568),and the cable will test ok. But when the
cable is tried on the LAN, it does not
work .This is because the lack of the
proper pairing causes excessive cross talk in
the cable, preventing the LAN from working.
This type of cable fault is sometimes call a
split pair or double split pair to detect this
type of fault, a more sophisticate tester
capable of performing a NEXT test(Near End
Cross Talk) must be used. Both the Pair
Master and LAN TDR can perform NEXT
tests.