Category 5(e) (UTP) colour coding table :
The following table shows the normal colour coding for category 5 cables (4 pair) based on the two standards supported by TIA/EIA (see also our primer on this topic)
We get occasional email about the difference between 568A and 568B wiring. Which one you use is a matter of local decision. These standards apply to the color code used within any SINGLE cable run - BOTH ENDS MUST USE THE SAME STANDARD. However, since they both use the same pinout at the connectors you can mix 568A and 568B cables in any installation.
We get occasional email about the difference between 568A and 568B wiring. Which one you use is a matter of local decision. These standards apply to the color code used within any SINGLE cable run - BOTH ENDS MUST USE THE SAME STANDARD. However, since they both use the same pinout at the connectors you can mix 568A and 568B cables in any installation.
100base-T Crossed cable (PC to PC or HUB to HUB):
Crossed cables are used to connect PCs to one other PC or to connect a HUB to a HUB. Crossed cable are sometimes called Crossover, Patch or Jumper cables. If your connection is PC to HUB you MUST use a Straight cable.
The following description shows the wiring at both ends (male RJ45 connectors) of the crossed cable. Note: The diagrams below shows crossing of all 4 pairs and allows for the use of cat3/4 cables with 100m LANs (100base-T4). Pairs 4,5 and 7,8 do not NEED to be crossed in 100base-TX wiring. See notes below.
NOTES:
All our crossed wiring is now done to the 100base-T4 spec (uses all 4 pairs, 8 conductors) which you can use with 10base-T networks - but NOT necessarily the other way around.
Many commercial 100m LAN cables seem not to cross pairs 4,5 and 7,8. If there is no cat3/4 wiring in the network this perfectly acceptable.
Gigabit Ethernet uses all 4 pairs so requires the full 4 pair (8 conductor) cross configuration (shown above).
If you are using Power-over-Ethernet (802.3af) then Mode A or Alternative A uses pairs 1,2 and 3,6 for both signals and power. Mode B or alternative B uses 4,5 and 7,8 to carry power. In all cases the spec calls for polarity insensitive implementation (using a diode bridge) and therefore crossing or not crossing pairs 4,5 and 7,8 will have no effect
The following description shows the wiring at both ends (male RJ45 connectors) of the crossed cable. Note: The diagrams below shows crossing of all 4 pairs and allows for the use of cat3/4 cables with 100m LANs (100base-T4). Pairs 4,5 and 7,8 do not NEED to be crossed in 100base-TX wiring. See notes below.
NOTES:
All our crossed wiring is now done to the 100base-T4 spec (uses all 4 pairs, 8 conductors) which you can use with 10base-T networks - but NOT necessarily the other way around.
Many commercial 100m LAN cables seem not to cross pairs 4,5 and 7,8. If there is no cat3/4 wiring in the network this perfectly acceptable.
Gigabit Ethernet uses all 4 pairs so requires the full 4 pair (8 conductor) cross configuration (shown above).
If you are using Power-over-Ethernet (802.3af) then Mode A or Alternative A uses pairs 1,2 and 3,6 for both signals and power. Mode B or alternative B uses 4,5 and 7,8 to carry power. In all cases the spec calls for polarity insensitive implementation (using a diode bridge) and therefore crossing or not crossing pairs 4,5 and 7,8 will have no effect
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