Registered jack
lastmod 2023-11-11created 2018-08-0211 edits
(This page is about the standardized telecommunication network interface, a wiring standard. For uses of modular connectors, see Modular connector.)
This page is about the registered jack (RJ) wiring standard. For other uses of modular connectors, see modular connector.
A registered jack (RJ) is a standardized telecommunication network interface for connecting voice and data equipment to services provided by a local exchange carrier or long-distance carrier.
Details
A registered jack (RJ) is a standardized telecommunication network interface for connecting voice and data equipment to a service provided by a local exchange carrier or long distance carrier. Registration interfaces were first defined in the Universal Service Ordering Code (USOC) system of the Bell System in the United States for complying with the registration program for customer-supplied telephone equipment mandated by the Federal Communications Commission (FCC) in the 1970s. They were subsequently codified in title 47 of the Code of Federal Regulations Part 68.
The specification includes physical construction, wiring, and signal semantics. Accordingly, registered jacks are primarily named by the letters RJ, followed by two digits that express the type. Additionally, letter suffixes indicate minor variations. For example, RJ11, RJ14, and RJ25 are the most commonly used interfaces for telephone connections for one-, two-, and three-line service, respectively. Although these standards are legal definitions in the United States, some interfaces are used worldwide.
The connectors used for registered jack installations are primarily the modular connector and the 50-pin miniature ribbon connector. For example, 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.
Categories
- Registered jack (RJ45, etc ...)
- Modular connector
- Twisted pair
- Unshielded twisted pair (UTP; cable)
8P8C
For how to connect, see Unshielded twisted pair.
Pin usage by communication method
- For voice lines => only 1 pair (pins 4, 5) or (pins 7, 8) is used
- For Ethernet 10/100 Mbps => only 2 pairs (4 wires) are used
- Transmit: pins 1, 2 pair (orange, pair 2)
- Receive: pins 3, 6 pair (green, pair 3)