EIA T-568A and T-569B
We wire T-568B everywhere -- when IPv6 is at 80 percent
penetration, we will re-examine the A standard.
Diagnosis tip
A block wired A, with a B far end will show this pattern:
12345678 B master
78145236 A end
Pin Number Designations for T568B
Color Codes for T568B |
Pin | color | pair | name |
1 | wh/or | 2 | TxData + |
2 | or | 2 | TxData - |
3 | wh/grn | 3 | RecvData+ |
4 | blu | 1 | |
5 | wh/blu | 1 | |
6 | grn | 3 | RecvData- |
7 | wh/brn | 4 | |
8 | brn | 4 | |
Note that the odd pin numbers are always the white with stripe color.
The wires connect to RJ-45 8-pin connectors as shown below:
RJ-45 wiring for Ethernet (T568B standard)

The wall jack may be wired in a different sequence because the wires are
often crossed inside the jack. The jack should either come with a wiring
diagram or at least designate pin numbers.
Note that the blue pair is on the center pins; this pair translates to the
red/green pair for ordinary telephone lines, which is also in the center
pair of an RJ-11. (green=wh/blu; red=blu)
from: http://www.johnscloset.net/wiring/
Crossover Cable |
 |
Straight Through Cable |
RJ-45 PIN |
RJ-45 PIN |
RJ-45 PIN |
RJ-45 PIN |
1 Rx+ |
3 Tx+ |
1 Tx+ |
1 Rc+ |
2 Rc- |
6 Tx- |
2 Tx- |
2 Rc- |
3 Tx+ |
1 Rc+ |
3 Rc+ |
3 Tx+ |
6 Tx- |
2 Rc- |
6 Rc- |
6 Tx- |
Note: The standard connector view shown is
color-coded for a straight thru cable
Category 5 wiring standards:
EIA/TIA 568A/568B and AT&T 258A define the wiring
standards and allow for two different wiring color codes.
Pin # |
Signal |
EIA/TIA
568A |
AT&T 258A, or EIA/TIA
568B |
Ethernet
10BASE-T 100BASE-T |
1 |
Transmit+ |
White/Green |
White/Orange |
X |
2 |
Transmit- |
Green/White or Green |
Orange/White or Orange |
X |
3 |
Receive+ |
White/Orange |
White/Green |
X |
4 |
N/A |
Blue/White or Blue |
Blue/White or Blue |
Not used *
|
5 |
N/A |
White/Blue |
White/Blue |
Not used *
|
6 |
Receive- |
Orange/White or Orange |
Green/White or Green |
X |
7 |
N/A |
White/Brown |
White/Brown |
Not used *
|
8 |
N/A |
Brown/White or Brown |
Brown/White or Brown |
Not used *
|
from: http://www.makeitsimple.com/how-to/dyi_crossover.htm
Crossover pattern

from: http://www.derose.net/steve/guides/wiring/CAT5crossover.jpg
T-568B pattern

from: http://www.johnscloset.net/wiring/RJ45.gif
Patch cable end colors

from: http://www.makeitsimple.com/how-to/rj45colors.gif
| | | Modified: Fri, 16 Dec 2005 13:55:12 -0500
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