RJ11

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 across the world.

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.

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.

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.

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.

Pinouts

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

In modern structured wiring Cat5e or Cat6 is commonly used in homes and buildings. The Cat 5e and Cat 6 data lines are often used for both voice or data. The color codes above are the standard and defined within wiring guides.

See also

• BS 6312 - British equivalent to RJ25
• 4P4C - Handset jack
• 8P8C - Eight position connector used with Ethernet
• Modified Modular Jack -- A variation used by Digital Equipment Corporation for serial computer connections
• Telephone plug - Includes a table of the countries where RJ-11 and other telephone connectors are used

External links

• The Basics of Telephone Wiring
• Home Phone Wiring Advice Page
• Doing your own telephone wiring
• Connecting a second phone line
• 8-conductor Silver Flat Phone Cable
• John R. Carlsen: On Wiring Modular Telephone Connectors