RJ-11 - Definition and Overview

RJ-11 is a physical interface often used for terminating twisted pair type cables. “RJ” stands for Registered Jack which is part of the United States Code of Federal Regulations. It has six pins or electrical connections.

Telephone signal polarisation and cable wiring in RJ-11

RJ-61/8P8C, RJ-25/6P6C, RJ-14/6P4C and RJ-11/6P2C Wiring

8P8C	6P6C	6P4C	6P2C	Pair	Wire	T/R	+/-	Color	Old
1				4	1	T4	+	white/brown
2	1			3	1	T3	+	white/green
3	2	1		2	1	T2	+	white/orange	black
4	3	2	1	1	2	R1	-	blue/white	red
5	4	3	2	1	1	T1	+	white/blue	green
6	5	4		2	2	R2	-	orange/white	yellow
7	6			3	2	R3	-	green/white
8				4	2	R4	-	brown/white

(T4 means 4th pair's tip wire, R2 means 2nd pair's ring wire, etc.)