The telephone jack, telecommunication jack or registered jack is a family of connectors and receptacles used for telephone, network, and signal wiring. The registered jack refers to the female modular receptacle specifically, although it is commonly accepted as the designation for both genders. Registered jacks are named by the letters RJ, followed by two digits that designate the type. Additionally, letter suffixes indicate minor variations.
Some Registered Jack examples include:
- eight-contact 8P8C plug (used for RJ45, RJ49, RJ61 and others)
- six-contact 6P6C plug used for RJ25
- four-contact 6P4C plug used for RJ14 (often also used instead of 6P2C for RJ11)
- four-contact 4P4C handset plug (also popularly called "RJ9", "RJ10", or "RJ22")
RJ11, RJ14, and RJ25 are the most commonly used interfaces for telephone connections. RJ11 uses a six-position two-conductor connector (6P2C), RJ14 uses a six-position four-conductor (6P4C) modular jack, while RJ21 uses a 25-pair (50-pin) miniature ribbon connector.
The RJ11 standard dictates a 2-wire connection, while RJ14 uses a 4-wire configuration, and RJ25 uses all six wires. The RJ abbreviations, though, only pertain to the wiring of the jack (hence the name registered jack); it is commonplace, but not strictly correct, to refer to an unwired plug connector by any of these names.
Related
- Ethernet RJ45 Wiring Reference
- Telephone RJ11 Wiring Reference
- Telephone System
- Telecommunication Jack