RJ11
From Free net encyclopedia
Image:Photo-RJ11-MF.jpg RJ11 is a physical interface often used for terminating telephone wires. It has six positions with two pins (electrical connections) installed at positions 3 and 4. RJ14 indicates that there is a second pair for an additional line on pins 2 and 5. RJ12 or RJ25 indicate that there is a third pair on pins 1 and 6.
The six-position connectors are commonly (but unofficially) designated as 6P2C, 6P4C, and 6P6C (where 'P' stands for 'positions' and 'C' stands for 'conductors'), respectively. RJ stands for registered jack, which is part of the Universal Service Ordering Code and the United States Code of Federal Regulations, though this connector is now coming into worldwide use. The U.S. is now almost completely converted, except for some much-older homes.
Like most other RJ connectors, this type of plug has a hinged locking tab that must be depressed to remove the plug from the wall jack. The disadvantage lies in the lightweight construction of the plug. If the plug were unhooked from the jack, and cord pulled free, the locking tab is subject to catching on the cord, desk, carpet, etc. and breaking it off. Some higher-quality cables incorporate a "snagless" plastic sleeve over the tab (or a redesigned tab) to prevent this, though this is almost exclusive to 8P8C data cables.
Pinouts
| 8P8C | 6P6C | 6P4C | 6P2C | Pair | Wire | T/R | +/- | Color | Old |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 4 | 1 | T4 | + | Image:Wire white brown stripe.svg white/brown | Image:Wire orange.svg orange | |||
| 2 | 1 | 3 | 1 | T3 | + | Image:Wire white green stripe.svg white/green | Image:Wire white.svg white (or slate) | ||
| 3 | 2 | 1 | 2 | 1 | T2 | + | Image:Wire white orange stripe.svg white/orange | Image:Wire black.svg black | |
| 4 | 3 | 2 | 1 | 1 | 2 | R1 | - | Image:Wire blue white stripe.svg blue | Image:Wire red.svg red |
| 5 | 4 | 3 | 2 | 1 | 1 | T1 | + | Image:Wire white blue stripe.svg white/blue | Image:Wire green.svg green |
| 6 | 5 | 4 | 2 | 2 | R2 | - | Image:Wire orange white stripe.svg orange | Image:Wire yellow.svg yellow | |
| 7 | 6 | 3 | 2 | R3 | - | Image:Wire green white stripe.svg green | Image:Wire blue.svg blue | ||
| 8 | 4 | 2 | R4 | - | Image:Wire brown white stripe.svg brown | Image:Wire brown.svg brown |
(T4 means 4th pair's tip wire, R2 means 2nd pair's ring wire, etc.)
Note that while the old solid color code was well established for pairs 1 and 2, there are several conflicting conventions for pairs 3 and 4. The colors shown above were taken from a vendor of "silver satin" flat 8-conductor phone cable that claims to be standard. At least one other vendor of flat 8-conductor cable uses the sequence blue, orange, black, red, green, yellow, brown and white/slate. If the conductors are wired straight through however, the color does not matter.
Note also that the flat 8-conductor "silver satin" cable traditionally used with 4-line analog telephones is unsuitable for use with Ethernet, even though both applications use the "RJ45" 8-position connector. Twisted pair cable and the pairings given in TIA-568A/B (which are different from the pairings shown above) must be used with Ethernet. The 8-conductor phone wiring is officially known as RJ-61. T1 lines use another wiring for the same connector, designated RJ48.
Most residences are wired with the full four-wire cable, but many only have the inner pair actually connected to anything, LocalTalk was designed to use only the outer pair (the black and yellow wires). Many homes also used the second pair for power, with a transformer wired into an outlet near one jack providing 24 or so volts DC to all phones in the house. Technically these would be RJ11, because there is still only one telephone line connected, although RJ14 cords are required to access whatever is on the second pair.
These connectors are sometimes also wired for RS-232 serial communication used on certain devices.
