Ethernet 10/100/1000 base-T Straight
	
01 Mar 1998

Straight cables are used to connect PCs or other equipment to a HUB or
Switch. If your connection is PC to PC or HUB to HUB you MUST use a Crossed
cable. These cables are sometimes called “whips”.

	
thumb|right|240px|8P8C modular plug pin positioning

	
RJ45 MALE CONNECTOR RJ45 MALE CONNECTOR To network interface card)

	
RJ45 MALE CONNECTOR RJ45 MALE CONNECTOR To hub



TIA/EIA 568A


Pin 	
Signal 	
TIA/EIA 568A 		
Pin 	
Signal 	
TIA/EIA 568A
1 
BI_DA+ (TX+) 
Pair 3 Wire 1 white/green 
1 
BI_DA+ (TX+) 
Pair 3 Wire
1
white/green
2 
BI_DA- (TX-) 
Pair 3 Wire 2 green 
2 
BI_DA- (TX-) 
Pair 3 Wire 2
green
3 
BI_DB+ (RX+) 
Pair 2 Wire 1 white/orange 
3 
BI_DB+ (RX+) 
Pair 2 Wire
1 white/orange
4 
BI_DC+ 
Pair 1 Wire 2 blue 
4 
BI_DC+ 
Pair 1 Wire 2 blue
5 
BI_DC- 
Pair 1 Wire 1 white/blue 
5 
BI_DC- 
Pair 1 Wire 1 white/blue
6 
BI_DB- (RX-) 
Pair 2 Wire 2 orange 
6 
BI_DB- (RX-) 
Pair 2 Wire 2
orange
7 
BI_DD+ 
Pair 4 Wire 1 white/brown 
7 
BI_DD+ 
Pair 4 Wire 1
white/brown
8 
BI_DD- 
Pair 4 Wire 2 brown 
8 
BI_DD- 
Pair 4 Wire 2 brown




TIA/EIA 568B


Pin 	
Signal 	
TIA/EIA 568A 		
Pin 	
Signal 	
TIA/EIA 568A
1 
BI_DA+ (TX+) 
Pair 2 Wire 1 white/orange 
1 
BI_DA+ (TX+) 
Pair 2 Wire
1 white/orange
2 
BI_DA- (TX-) 
Pair 2 Wire 2 orange 
2 
BI_DA- (TX-) 
Pair 2 Wire 2
orange
3 
BI_DB+ (RX+) 
Pair 3 Wire 1 white/green 
3 
BI_DB+ (RX+) 
Pair 3 Wire
1
white/green
4 
BI_DC+ 
Pair 1 Wire 2 blue 
4 
BI_DC+ 
Pair 1 Wire 2 blue
5 
BI_DC- 
Pair 1 Wire 1 white/blue 
5 
BI_DC- 
Pair 1 Wire 1 white/blue
6 
BI_DB- (RX-) 
Pair 3 Wire 2 green 
6 
BI_DB- (RX-) 
Pair 3 Wire 2
green
7 
BI_DD+ 
Pair 4 Wire 1 white/brown 
7 
BI_DD+ 
Pair 4 Wire 1
white/brown
8 
BI_DD- 
Pair 4 Wire 2 brown 
8 
BI_DD- 
Pair 4 Wire 2 brown


Notes

It’s important that each pair is kept as a pair. TX+ & TX- must be in the
pair, and RX+ & RX- must together in another pair. (Just as the table above
shows).
The + side of each pair is called the “tip” and the - side is called
the “ring”, a reference to old telephone connectors.
T568A and T568B are the two color codes used for wiring eight-position RJ45
modular plugs. Both are allowed under the ANSI/TIA/EIA wiring standards. The
only difference between the two color codes is that the orange and green
pairs are interchanged. T568A wiring pattern is recognized as the preferred
wiring pattern for this standard because it provides backward compatibility
to both one pair and two pair USOC wiring schemes. The T568B standard
matches the older ATA&T 258A color code and is/was(?) the most widely used
wiring scheme. It is also permitted by the ANSI/TIA/EIA standard, but it
provides only a single pair backward compatibility to the USOC wiring
scheme. The U.S. Government requires the use of the preferred T568A standard
for wiring done under federal contracts.

References

http://www.duxcw.com/faq/network/diff568ab.htm
http://www.zytrax.com/tech/layer_1/cables/tech_lan.htm