RJ11, RJ14, RJ25

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Two views of an RJ25 6P6C crimp-on style connector
Two views of an RJ25 6P6C crimp-on style connector

RJ11 is a physical interface often used for terminating telephone wires. It is probably the most familiar of the registered jacks, being used for single line POTS telephone jacks in most homes and offices in North America and many other countries.

RJ14 is similar, but for a two line telephone jack, and RJ25 is for a three line jack. RJ61 is a similar registered jack for four lines. The telephone line cord and its plug are more often a true RJ11 with only two conductors.

Contents

[edit] Contact arrangement

All of these registered jacks are described as containing a number of potential contact "positions" and the actual number of contacts installed within these positions. RJ11, RJ14, and RJ25 all use six-position modular connectors.

[edit] RJ11 wiring

An RJ11 is nearly always a 6P4C (six position, four conductor) jack, with four wires (two of them unused) running to a central junction box, using two of its six possible contact positions to connect tip and ring. It could therefore be wired with a 6P2C variety of modular jack, but this is rarely done.

The extra wires are used for various things such as a ground for selective ringers, low voltage for a dial light, or as an 'anti-tinkle' circuit to prevent a pulse dialing phone from ringing the bell on other extensions. With tone dialing these are not required, so the connectors are used to provide flexibility so the jack can be rewired later as RJ14 or to supply additional power for special uses.

[edit] Powered version of RJ11

In the powered version, Pins 2 and 5 (black and yellow) may carry low voltage AC or DC power. While the phone line itself supplies enough power for most telephone terminals, old telephone terminals with incandescent lights in them (such as the classic Western Electric Princess and Trimline telephones) need more power than the phone line can supply. Typically, the power on Pins 2 and 5 comes from a transformer plugged into a wall near one jack, supplying power to all of the jacks in the house. Trimline and Princess phone dial lights are rated at 6.3 volts and the transformer output is typically around 5 volts, providing a long service life for the incandescent lamps.

[edit] Pinouts

pin RJ25 RJ14 RJ11 Pair T/R ± Color Old
1 X 3 T + Pair 4 Wire 1 white/green Pair 4 Wire 1 orange
2 X X 2 T + Pair 2 Wire 1 white/orange Pair 2 Wire 1 Old black
3 X X X 1 R - Pair 1 Wire 2 blue/white Pair 1 Wire 2 Old red
4 X X X 1 T + Pair 1 Wire 1 white/blue Pair 1 Wire 1 Old green
5 X X 2 R - Pair 2 Wire 2 orange/white Pair 2 Wire 2 Old yellow
6 X 3 R - Pair 3 Wire 2 green/white Pair 3 Wire 2 blue

While the old solid color code was well established for pairs 1 and 2, there are several conflicting conventions for pair 3. The colors shown above were taken from a vendor of "silver satin" flat 8-conductor phone cable that claims to be standard. Other 6 pair solid (old) bellwire cables may substitute white for orange. At least one other vendor of flat 8-conductor cable uses the sequence blue, orange, black, red, green, yellow, brown and white/slate.

Holding the connector in your hand tab side down with the cable opening toward you, the pins are numbered 1-6, left to right.

[edit] See also

[edit] External links

v • d • e
USOC registered jacks
RJ9 · RJ11 · RJ12 · RJ14 · RJ21 · RJ25 · RJ45 · RJ48 · RJ50 · RJ61