RJ12 | Technical features | instrumentic.info

The difference is the wiring and the number of strands used
The difference is the wiring and the number of strands used

RJ12

The RJ11 and RJ12 standards are quite close. The same six-slot connector is used.

The only difference between the two is the wiring and the number of strands that are used.

RJ12 is a standard 6P6C wiring. This means that there are 6 strands that are wired in the connector. RJ11 is a 6P4C wiring and has only four wires connected, the other two are not used.

RJ12 uses six slots while RJ11 uses only four of the six available slots.
RJ12 uses six slots while RJ11 uses only four of the six available slots.

Difference between RJ11 and RJ12

Despite the differences, the two wiring standards are used for the same purpose : for telephone lines.
Generally the center pair is used. But there are also other applications that use the RJ12 standard.
Key phone systems and PBX can take advantage of the two additional connections. For this reason, RJ12 is not very common.
RJ11, on the other hand, is common because it is used by the majority of phone companies in the world.

The two additional lines that are available with the RJ12 standard can become interesting with a private auto-switch that adds lines.

- RJ11 and RJ12 use the same connector with six locations.
- RJ11 and RJ12 differ only in wiring.
- RJ12 uses all six slots while RJ11 uses only four of the six slots available.

RJ12 RJ11 use
1 power supply + 5V
2 1 unused
3 2 data transmission
4 3 GND
5 4 power supply + 5V
6 unused