RJ11 | Technical Characteristics | instrumentic.info

What is RJ11 ?
What is RJ11 ?


RJ11 – Regitered Jack 11 – is used for the landline. It is an international standard for connecting the fixed telephone to the telecommunications network.

RJ11 uses a 6-slot connector. In this one RJ11 has 6 slots (positions) and two drivers, the standard is written 6P2C.

The information transmitted on the line can be digital (DSL) or analog.

The telephone cable that arrives at the subscriber has 4 conductors grouped into 2 colored pairs called twisted pairs. Only the two central conductors are used for the line.

RJ11 wiring
RJ11 wiring


The terms are used Tip And Ring which refer to the beginnings of telephony when long audio sockets were used to connect the customer's line. The translation is tip and ring, they correspond to the 2 conductors needed for the operation of a line.

The voltage in a subscriber is usually 48 V between Ring And Tip With Tip near the mass and Ring -48 V.
Copper conductors therefore go by 2 in all RJ sockets and have very distinct colors.

The two central contacts, numbered 2 and 3, are used for the telephone line signal and the standard colors guide the user or technician.

Table of wiring RJ11-RJ12-RJ25 :

Position Contacter Number RJ11 Contacter Number RJ12 Contacter Number RJ25 Twisted pair no. T \ R colors France U.S. colors Germany colors Old colors
1 . . 1 3 T green white white or orange Purple White
2 . 1 2 2 T orange white Black Green Black
3 1 2 3 1 R white blue Red White Red
4 2 3 4 1 T blue white Green Brown Green
5 . 4 5 2 R white orange Yellow Yellow Yellow
6 . . 6 3 R white green blue or brown Grey Blue

Contacts other than the two central contacts are variously used for a second or third telephone line or, for example, for the mass of selective ringtones, a low-voltage light dial power supply or to prevent the ringing of pulse-numbering phones.


RJ11 is a telephone connector that connects a single line. The RJ11 has six positions and two contacts (6P2C).
RJ12 is a telephone connector that connects two lines. The RJ12 has six positions and four contacts (6P4C).
RJ14 is also a six-position, four-contact telephone connector that connects two lines (6P4C).
RJ25 is a telephone connector that connects three lines. The RJ25 therefore has six positions and six contacts (6P6C).
RJ61 is a similar socket for four lines that uses an 8P8C connector.

The RJ45 socket also has 8 connectors but is rarely used in phone applications. This version of the RJ connector (8P8C) is used in Ethernet networks.

here the list

Changes in standards and telephone sockets
Changes in standards and telephone sockets

RJ11 examples of variations

The RJ standards have many different configurations. Each country has standardized its telephone sockets. There are approximately 44 different variations in RJ11 standards and catches.

RJ standards are U.S.-born definitions, but some are used around the world. The continuous tension between the two links of the RJ11 connectors may vary from country to country.
Adapters can be used from one country to another depending on the wiring.

In Germany there is the TAE standard, it covers two types of TAE : F ( "Fernsprechgerät" : for phones) And N ( "Nebengerät" or so "Nichtfernsprechgerät"Other devices such as answering machines and modems). U-coded plugs and plugs are universal connectors that are suitable for both types of devices.

In England there is the standard BS 6312, the connectors are similar to the RJ11 connectors, but have a hook mounted on the side, rather than a hook mounted at the bottom, and are physically incompatible.
This standard is also used in many other countries.

In Spain, a Spanish royal decree defines the use of RJ11 and RJ45.
In Belgium, there are several types of RJ11 wiring with 2 or 4 links.

Wiring the \T\ socket
Wiring the \T\ socket

Taking care of T

The F-010 phone socket or in "T" or so "gigogne" was installed by France Telecom until the end of 2003. This socket uses 8 standard connections, each of different color (grey, white, blue, purple, gray, brown, yellow, orange).
However, one phone only needs two contacts (usually grey and white) to function, the others being used mainly for faxes.

Outside of France, these catches are used in many other countries.