Straight And Crossover Cable Configuration - NetComm NB9 User Manual

Straight and crossover cable configuration

There are two types of the wiring: Straight-Through Cables and Crossover Cables. Category 5 UTP/STP cable
has eight wires inside the sheath. The wires form four pairs. Straight-Through Cables has same pinouts at
both ends while Crossover Cables has a different pin arrangement at each end.
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 fi rst 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
Cross-Over Cabling
Note: To prevent loss of signal, make sure that the length of any twisted-pair connection does not exceed 100 metres.
NB9/NB9W ADSL2+ VoIP Router
YML790 Rev1
Figure 3
Wire
1
2
3
6
Figure 4
Wire
1
2
3
6
Becomes
1
2
3
6
Becomes
3
6
1
2
103