RJ12 | Technical Characteristics | instrumentic.info

RJ12 uses all six locations while RJ11 uses only four.
RJ12 uses all six locations while RJ11 uses only four.

RJ12

RJ12 - Registered Jack 12 - is a standard of the same family as RJ11, RJ13 and RJ14. The same six-slot connector is used.

RJ12 has 3 pairs of copper strands allowing the exchange of information on 3 lines, the other standards allow exchanges only on one or two lines.

RJ12 allows the connectivity of telephone lines in companies while in general RJ11 is aimed at individuals.

The terms Tip and Ring are used to refer to the beginnings of telephony when long audio sockets connected the customer's line. The translation is 'point' and 'ring', they correspond to the 2 conductors needed for the operation of a line.
The voltage in a subscriber is usually 48V between drivers Ring And Tip With Tip near the mass and Ring -48 V.
Copper conductors therefore go by 2 in all RJ sockets and have distinct colors.
See the chart.

RJ12 is a 6P6C connector - RJ11 is a 6P2C wiring
RJ12 is a 6P6C connector - RJ11 is a 6P2C wiring

Differences between RJ11 and RJ12

The two standards differ in wiring and the number of useful contacts.
Like RJ11, the RJ12 socket is made up of thin copper cables and connection contacts.
RJ12 has 3 pairs of copper strands and RJ11 only one.

Between RJ11 and RJ12 to distinguish these differences, the names 6P6C, 6P4C, 6P2C, 4P2C are used.
RJ12 is a 6P6C connector. This means that there are 6 contacts that are wired in the socket.
RJ11 is a 6P2C wiring and has only 2 connected contacts, the others are not used.
6P4C corresponds to the reference RJ13 and RJ14.

- 6P means 6 connections or Positions .
- 6C,4C or 2C mean 6.4 or 2 contacts used i.e. containing strands.

RJ12 RJ11 T / R color code UTP (modern) old color code (cat3)
1 T green/white White
2 1 T white/orange Black
3 2 R blue/white Red
4 3 T white/blue Green
5 4 R orange/white Yellow
6 R white/green Blue

RJ12 :  Key systems and PBX
RJ12 : Key systems and PBX

RJ12 : Key systems and PBX (Private Branch Exchange)

Applications of RJ12 : key systems and PBX (Private Branch Exchange)
There are RJ12-specific telephone systems : key telephone systems and PBX. These systems allow companies to offer telephones to all their employees. Both types of systems offer features such as voicemail and waiting music.

A key system offers these services, but with only about twenty extensions.
A PBX system can include thousands of extensions. Most PBX systems offer features such as call duration and phone call tracking, while key systems don't.

In a nutshell


Comparison RJ12 - RJ11 :
- RJ12 and RJ11 use the same socket with six locations.
- RJ12 and RJ11 differ only in the wiring and the number of lines that can be transmitted.
- RJ12 uses all six slots while RJ11 uses only two of the six slots available.
- RJ12 serves for businesses and in general RJ11 for individuals.