Making a RJ45 cable tester

Crossover Cable Pin-out-
One End
----
Other End
Pin 1

Pin 3
Pin 2

Pin 6
Pin 3

Pin 1
Pin 4

Pin 4
Pin 5

Pin 5
Pin 6

Pin 2
Pin 7

Pin 7
Pin 8

Pin 8
Straight Through Connection
Pin 1 - TxD+ Pin 2 - TxD-Pin 3 - RxD+Pin 4 - Pin 5 - Pin 6 - RxD-Pin 7 -Pin 8 -
Cable: Here is what the internals of the cable look like:
Figure 1 - Internal Cable Structure and Color Coding
RJ45 Ends: Here is a diagram and pinout:
Figure 2 - RJ45 Jack and Plug Pinout

Ethernet Cables:
Standard, Straight-Through Wiring (both ends are the same):
RJ45 Pin #
Wire Color
Wire Diagram
Signal*
1
White/Orange

Transmit+
2
Orange

Transmit-
3
White/Green

Receive+
4
Blue

Unused
5
White/Blue

Unused
6
Green

Receive-
7
White/Brown

Unused
8
Brown

Unused
Table 1 - Straight-Through Cable Pinout

Cross-Over Cable:
RJ45 Pin # (END 1)
Wire Color
Diagram End #1
1
White/Orange

2
Orange

3
White/Green

4
Blue

5
White/Blue

6
Green

7
White/Brown

8
Brown

RJ45 Pin # (END 2)
Wire Color
Diagram End #2
1
White/Green

2
Green

3
White/Orange

4
Blue

5
White/Blue

6
Orange

7
White/Brown

8
Brown

Tables 2 & 3 - Cross-Over Cable Pinouts


Cross Cabling:
Wiring Diagrams for Straight Through, Cross Over and Y cables
Note: The hook is underneath in all cases and Pin one is always on the Left
Straight Through Cable
Color Code
Color
Pin 1 Pin 2 Pin 3 Pin 4 Pin 5 Pin 6 Pin 7 Pin 8
white orange orange white green blue white blue green white brown brown

Cross Over Cable
Color Code
Color
Pin 1 Pin 2 Pin 3 Pin 4 Pin 5 Pin 6 Pin 7 Pin 8
white green green white orange blue white blue orange white brown brown


Y Cable
Color Code
Color
Pin 1 Pin 2 Pin 3 Pin 6
Pin 1 Pin 2 Pin 3 Pin 6
white orange orange white green green
blue white blue white brown brown