RJ12

RJ12 - Registered Jack 12 - is a standard of the same family as RJ11

RJ11 - Registered Jack 11 - is used for the landline telephone. It is an international standard that is used to connect the landline telephone to the Telecommunications network. RJ11 uses a 6-slot connector. In it RJ11 has 6 slots (positions) and two conductors, the standard is written 6P2C.
The information transmitted on the line can be digital (DSL) or analog.

, 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

RJ11

RJ11 - Registered Jack 11 - is used for the landline telephone. It is an international standard that is used to connect the landline telephone to the Telecommunications network. RJ11 uses a 6-slot connector. In it RJ11 has 6 slots (positions) and two conductors, the standard is written 6P2C.
The information transmitted on the line can be digital (DSL) or analog.

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

Differences between RJ11 and RJ12

The two standards differ in wiring and the number of useful contacts.
Like RJ11

RJ11

RJ11 - Registered Jack 11 - is used for the landline telephone. It is an international standard that is used to connect the landline telephone to the Telecommunications network. RJ11 uses a 6-slot connector. In it RJ11 has 6 slots (positions) and two conductors, the standard is written 6P2C.
The information transmitted on the line can be digital (DSL) or analog.

, the RJ12 socket is made up of thin copper cables and connection contacts.
RJ12 has 3 pairs of copper strands and RJ11

RJ11

RJ11 - Registered Jack 11 - is used for the landline telephone. It is an international standard that is used to connect the landline telephone to the Telecommunications network. RJ11 uses a 6-slot connector. In it RJ11 has 6 slots (positions) and two conductors, the standard is written 6P2C.
The information transmitted on the line can be digital (DSL) or analog.

only one.

Between RJ11

RJ11

RJ11 - Registered Jack 11 - is used for the landline telephone. It is an international standard that is used to connect the landline telephone to the Telecommunications network. RJ11 uses a 6-slot connector. In it RJ11 has 6 slots (positions) and two conductors, the standard is written 6P2C.
The information transmitted on the line can be digital (DSL) or analog.

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

RJ11

RJ11 - Registered Jack 11 - is used for the landline telephone. It is an international standard that is used to connect the landline telephone to the Telecommunications network. RJ11 uses a 6-slot connector. In it RJ11 has 6 slots (positions) and two conductors, the standard is written 6P2C.
The information transmitted on the line can be digital (DSL) or analog.

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 RJ12 UTP ( modern)	old color code (cat3)
1		T	████ I_____I	I_____I
2	1	T	I_____I ████	████
3	2	R	████ I_____I	████
4	3	T	I_____I ████	████
5	4	R	████ I_____I	████
6		R	I_____I ████	████

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.