RJ-45 Ethernet Cable

Pin Number Designations:  (clip down end facing away)

Straight Through Configuration (Pass Through)
Color Codes for T568B  (for both RJ45 plugs for a pass-through cable)
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

* Hub to Computer connection: T568B on each end.

Crossover Configuration 
Color Codes for T568A  (for the second RJ45 plug on cable)
Pin   color  pair  name
---   -----  ----  ---------
1     wh/grn  2    TxData +
2     grn     2    TxData -
3     wh/or   3    RecvData+
4     blu     1
5     wh/blu  1
6     or      3    RecvData-
7     wh/brn  4
8     brn     4  
 
* Hub to Hub or Computer to Computer connection:  one end T568A, other end T568B (Crossover Cable).
Basically the Transmit and Receive are swapped with this configuration.

Odd pin numbers are always the white with stripe color.

The pairs designated for 10BaseT Ethernet are Orange and Green. The other two pairs, Brown and Blue, can be
used for a second Ethernet line or for phone connections.

The Blue pair is on the center pins and conveniently corresponds to the Red and Green pair in a normal phone line.
The connections shown are specifically for an RJ45 plug (the thing on the end of the wire). The wall jack may be
wired in a different sequence because the wires are actually crossed inside the jack. The jack should either come
with a wiring diagram or at least designate pin numbers that you can match up to the color code below.