Straight-through cabling, Cross-over cabling – NetComm NP2500 User Manual
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NP2500 24-Port 10/100 PoE + 2-Port 10/100/1000 WebSMART Switch User Guide
YML842 Rev1
In a straight-through cable, wires 1,2,3,4,5,6,7 and 8 at one end of the cable are still wires 1~8 at the other
end. In a crossover cable, the wires of 1,2,3,6 are reversed so that wire 1 become 3 at the other end of the
cable, 2 becomes 6, and so forth.
To determine which wire is wire 1, hold the RJ-45 cable tip with the spring clip facing towards the ground
and the end pointing away from you. The copper wires exposed upwards to your view. The first wire on the
far left is wire 1. You can also refer to the illustrations and charts of the internal wiring on the following page.
Straight-Through Cabling
Figure 3
Wire
Becomes
1
1
2
2
3
3
6
6
Cross-Over Cabling
Figure 4
Wire
Becomes
1
3
2
6
3
1
6
2
Note:
To prevent loss of signal, make sure that the length of any twisted-pair connection does
not exceed 100 metres.