
Eight lines of each RJ45 socket are separated into four pairs of FXS line sequences.
RJ45 position
RJ45 lines definition
Four-pair FXS line sequences
FXS port number
Pin
Signal
UTP Colour
Analog Line Pair
1
1
TX+
White Orange
Tip 1
1
St
Pair
1
2
TX-
Orange
Ring 1
3
RX+
White Green
Tip 2
2
nd
Pair
2
4
No Signal
Blue
Tip 3
3
rd
Pair
3
5
No Signal
White Blue
Ring 3
6
RX-
Green
Ring 2
2
nd
Pair
2
7
No Signal
White Brown
Tip 4
4
th
Pair
4
8
No Signal
Brown
Ring 4
2
1
TX+
White Orange
Tip 1
1
St
Pair
5
2
TX-
Orange
Ring 1
3
RX+
White Green
Tip 2
2
nd
Pair
6
4
No Signal
Blue
Tip 3
3
rd
Pair
7
5
No Signal
White Blue
Ring 3
6
RX-
Green
Ring 2
2
nd
Pair
6
7
No Signal
White Brown
Tip 4
4
th
Pair
8
8
No Signal
Brown
Ring 4
3
1
TX+
White Orange
Tip 1
1
St
Pair
9
2
TX-
Orange
Ring 1
3
RX+
White Green
Tip 2
2
nd
Pair
10
4
No Signal
Blue
Tip 3
3
rd
Pair
11
5
No Signal
White Blue
Ring 3
6
RX-
Green
Ring 2
2
nd
Pair
10
7
No Signal
White Brown
Tip 4
4
th
Pair
12
8
No Signal
Brown
Ring 4
4
1
TX+
White Orange
Tip 1
1
St
Pair
13
2
TX-
Orange
Ring 1
3
RX+
White Green
Tip 2
2
nd
Pair
14
4
No Signal
Blue
Tip 3
3
rd
Pair
15
5
No Signal
White Blue
Ring 3
6
RX-
Green
Ring 2
2
nd
Pair
14
7
No Signal
White Brown
Tip 4
4
th
Pair
16
8
No Signal
Brown
Ring 4
5
1
TX+
White Orange
Tip 1
1
St
Pair
17
2
TX-
Orange
Ring 1
3
RX+
White Green
Tip 2
2
nd
Pair
18
4
No Signal
Blue
Tip 3
3
rd
Pair
19
5
No Signal
White Blue
Ring 3
6
RX-
Green
Ring 2
2
nd
Pair
18
7
No Signal
White Brown
Tip 4
4
th
Pair
20
8
No Signal
Brown
Ring 4
6
1
TX+
White Orange
Tip 1
1
St
Pair
21
2
TX-
Orange
Ring 1
3
RX+
White Green
Tip 2
2
nd
Pair
22
4
No Signal
Blue
Tip 3
3
rd
Pair
23
5
No Signal
White Blue
Ring 3
6
RX-
Green
Ring 2
2
nd
Pair
22
7
No Signal
White Brown
Tip 4
4
th
Pair
24
8
No Signal
Brown
Ring 4
7
1
TX+
White Orange
Tip 1
1
St
Pair
25
2
TX-
Orange
Ring 1
3
RX+
White Green
Tip 2
2
nd
Pair
26
4
No Signal
Blue
Tip 3
3
rd
Pair
27
5
No Signal
White Blue
Ring 3
6
RX-
Green
Ring 2
2
nd
Pair
26
7
No Signal
White Brown
Tip 4
4
th
Pair
28
8
No Signal
Brown
Ring 4
8
1
TX+
White Orange
Tip 1
1
St
Pair
29
2
TX-
Orange
Ring 1
3
RX+
White Green
Tip 2
2
nd
Pair
30
4
No Signal
Blue
Tip 3
3
rd
Pair
31
5
No Signal
White Blue
Ring 3
6
RX-
Green
Ring 2
2
nd
Pair
30
7
No Signal
White Brown
Tip 4
4
th
Pair
32
8
No Signal
Brown
Ring 4