Difference Between RJ11 and RJ14 and RJ25 and RJ12 in Structured Cabling

RJ11 vs RJ14 vs RJ25 vs RJ12 in Structured Cabling

RJ 11 and RJ12 are two different standards in structured cabling. RJ11 is 6P4C type of wiring and RJ12 is 6P6C wiring standard. RJ is acronym to Registered Jack. RJ family has lots of standards like RJ9, RJ11, RJ12, RJ13, RJ14, RJ45, RJ48, RJ15, RJ61, RJ71 and more. The last 2 digits specify the wiring standards.6P4C connector acronym for 6 Position 4 Conductor. So, RJ 11 falls under 6 positions 4 conductor standard whereas RJ12 falls under 6 positions 6 conductor standards.


RJ 11 is a wiring standard mostly used in telephone systems. RJ11 is 6P4C wiring standard where only 4 conductors (wires) connected to the physical connector and 2 slots or positions on the socket is free. That means 2 phones can be connected via this connector. RJ11, RJ14 and RJ25 all use the 6P6C physical connector but the numbers of conductors or wires differ. RJ11 generally connects with 2 wires, RJ14 connects with 4 wires and RJ25 connects with 6 wires respectively allowing 1, 2 or 3 phone lines respectively.

RJ11 cables generally sold as 6P4C with 4 wires (2 pairs) running from central junction box but only one line is being used via single pair and other pair is kept free for future use if necessary.


RJ12 is a 6P6C wiring standards means, 6 positions of the socket will be occupied by 6 conductors or wires. Normal home telephones used RJ11 and corporate PBX using key phones or Digital Phone Systems uses generally RJ12. In some phones we can configure 3 phone lines (3 CO lines) for an operator to answer 3 different phone lines. Those types of phones are generally connected via RJ12 or RJ25.

Depends on our needs we can select RJ11, RJ12, RJ14 and RJ25. But in general home connections are RJ11.

Difference between RJ11, RJ12, RJ14 and RJ24

1. RJ11, RJ14, RJ25 and RJ12 all use the same physical connector.

2. RJ 11 connects with single pair cable (2 conductors), RJ14 double pair or 4 conductors, RJ12 and RJ25 connects 3 pair or 6 conductors respectively to carry 1, 2 or 3 phone lines.

3. RJ11 is generally used in home connections and appliances whereas RJ12 is mostly used in corporate wirings

  • http://www.cabling-design.com/ Cabling Guy

    Umm… Gotta be careful with that RJ14 – it’s often used to describe a connector at the both ends of a coiled phone handset cable. It may not be a correct RJ denomination but it’s very pervasive and has pretty much taken over the otherwise unused original RJ14