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(hardware, communications)
An American-style telephone jack with six possible connections. A telephone normally uses two pairs of wires. Often found on the back of US-manufactured modems or for connection to a leased line.


(Registered Jack-11) A telephone interface that uses a cable of twisted wire pairs and a modular jack with two, four or six contacts. RJ-11 is the common connector for plugging a telephone into the wall and the handset into the telephone. See modular connector.

RJ-11, 14, 25 - One, Two and Three Lines
RJ-11 cables can hold six wires for up to three telephone lines, and their nomenclature is technically RJ-11, RJ-14 or RJ-25 depending on the number of lines (see chart below).

RJ-21X, RJ-26X and RJ-27X
For PBX and other telecom connections, RJ-21X, 26X and 27X cables use a 50-pin Centronics-style "Miniature Ribbon" connector to handle 25 telephone lines in one cable.

C and W
The C refers to a desk phone jack, such as RJ-11C, while RJ-11W means a wall-mounted jack. See modular connector.

RJ-11 Connectors
Four-wire RJ-11 connectors (6P4C) are commonly used for telephone handsets and wall outlets. The six-wire variation (6P6C) is used for three telephone lines (see below).

Jack Positions (P)RJ     U.S.                 andType   Wire Pair Colors    Contacts (C)

  RJ-11  Line 1 - red-green     6P2C

  RJ-14  Line 1 - red-green     6P4C
         Line 2 - yellow-black

  RJ-25  Line 1 - red-green     6P6C
         Line 2 - yellow-black
         Line 3 - blue-white
References in periodicals archive ?
Instead of hooking a stereo's + and -- posts to a slave jack, and running phone line extension cord with RJ-11 plugs at each end to another jack in the phone circuit, you can skip the slave jacks and attach the stereo leads to the stripped end of a length of phone wire with an RJ-11 at the far end.
This critter looks very much like the RJ-11 except that it can hold eight wires.
The RJ-11 voice interface ports enable one FXS voice interface to connect an analog phone for low-cost calling via VoIP.
The PC CommLink contains 8 feet of RJ-11 cable that can extend and retract.
The TinyModem is an extremely small modem module with an RJ-11 connector.
The cordset uses a standard RJ-45 or RJ-11 plug and adds strain relief and a locking mechanism that seals the connector when mated with an appropriate receptacle.
The GL Analog Test Set (ATS) supports two analog ports with RJ-11 interfaces and may be connected to any U.
90 Winmodem controllerless modem from the RJ-11 phone jack to the host PCI interface, the new system will be used by 3Com in its mobile, desktop and combo Ethernet and broadband consumer communications products.