RJ45 Ethernet & RJ11 Telephone Cables

Standard, Straight-Through Wiring (both ends are the same):

RJ45 Pin #

Wire Color
(T568A)

Wire Diagram
(T568A)

10Base-T Signal
100Base-TX Signal

1000Base-T Signal

1

White/Green

Transmit+

BI_DA+

2

Green

Transmit-

BI_DA-

3

White/Orange

Receive+

BI_DB+

4

Blue

Unused

BI_DC+

5

White/Blue

Unused

BI_DC-

6

Orange

Receive-

BI_DB-

7

White/Brown

Unused

BI_DD+

8

Brown

Unused

BI_DD-

Straight-Through Cable Pin Out for T568A

RJ45 Pin #

Wire Color
(T568B)

Wire Diagram
(T568B)

10Base-T Signal
100Base-TX Signal

1000Base-T Signal

1

White/Orange

Transmit+

BI_DA+

2

Orange

Transmit-

BI_DA-

3

White/Green

Receive+

BI_DB+

4

Blue

Unused

BI_DC+

5

White/Blue

Unused

BI_DC-

6

Green

Receive-

BI_DB-

7

White/Brown

Unused

BI_DD+

8

Brown

Unused

BI_DD-

Straight-Through Cable Pin Out for T568B

Pair 1 (T1 & R1)

Usually the primary dial tone or talk circuit is wired to the center two pins (pins 3 & 4) and is the white/blue and blue/white pair (AKA: T1 & R1 – tip 1 and ring 1). A standard single line phone draws dial tone from these center pins.

NOTE: The type of wiring shown here is known as USOC (pronounced U-sock). See background below.

The multi-conductor cables attached to RJ11 connectors usually have colored sheaths.

position

RJ25 pin

RJ14 pin

RJ11 pin

Pair

T/R

±

Cat 5e/6 colors

Colors

Old colors

1

1

   

3

T

+

white/green

white/green

white

2

2

1

 

2

T

+

white/orange

white/orange

black

3

3

2

1

1

R

 blue

blue/white

red

4

4

3

2

1

T

+

white/blue

white/blue

green

5

5

4

 

2

R

 orange

orange/white

yellow

6

6

   

3

R

 green

green/white

blue

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