Registered Jack (RJ) is a standardized physical network interface connecting voice and data equipment. It was developed by the Electronic Industries Association (EIA) in 1976 to replace earlier telephone connection standards, such as the Western Electric Registered Jack designations. RJ connectors are primarily used in telephone and Ethernet networks but can also be found on other types of communications systems, including fiber optic and coaxial cables. They provide reliable connections between devices while allowing for easy installation, maintenance, and reconfiguration when needed.
There are several types of RJ connectors, including:
- RJ-11: The most common type of RJ connector is the RJ-11, which is used for telephone connections. It has 4 or 6 pins.
- RJ-14: The RJ-14 connector is similar to the RJ-11, but it has 6 pins and is typically used for 2-line telephone connections.
- RJ-45: The RJ-45 connector is most commonly used for Ethernet connections and has 8 pins.
- RJ-21: The RJ-21 connector is a large-scale version of the RJ-45, and it has 50 pins; it is used for high-density connections in data centers or other large-scale networks.
- RJ-48: The RJ-48 connector is similar to the RJ-45, but it has 8 or 10 pins and is typically used for T1 and E1 connections in telecommunications networks.
- RJ-50: The RJ-50 connector is similar to the RJ-21, but it has 10 pins and is used for serial connections in industrial and other specialized environments.
- RJ-61: The RJ-61 connector is similar to the RJ-11, but it has 8 pins and is used for 4-line telephone connections.
- RJ-62: The RJ-62 connector is similar to the RJ-14, but it has 8 pins and is used for 4-line telephone connections.
The most widely used connectors are RJ-45 and RJ-11 for Ethernet networks and telephone connections, respectively.
- RJ-69: The RJ-69 connector is similar to the RJ-45, but it has 6 pins and is used for Token-Ring networks. This type of connector is not commonly used, as Ethernet networks have largely replaced token-Ring networks.
- RJ-72: The RJ-72 connector is specialized in ISDN (Integrated Services Digital Network) connections. It has 16 or 24 pins, and it’s typically used for high-speed digital data, voice, and video applications.
- RJ-73: The RJ-73 connector is similar to the RJ-72, but it has 8 pins and is used for ISDN BRI (Basic Rate Interface) connections.
- RJ-74: The RJ-74 connector is similar to the RJ-72, but it has 30 pins and is used for ISDN PRI (Primary Rate Interface) connections.
- RJ-88: The RJ-88 connector is similar to the RJ-45 but has 8 pins and is used for ATM (Asynchronous Transfer Mode) connections.
- RJ-89: The RJ-89 connector is similar to the RJ-45 but has 8 pins and is used for PoE (Power over Ethernet) connections.
It’s important to note that not all of these connectors are commonly used, and most are specialized connectors used in specific networks or applications.
RJ-69, RJ-72, RJ-73, RJ-74, RJ-88, RJ-89 are not standard connectors and are not commonly used in the industry.
The most commonly used connectors for Ethernet networks are the RJ-45 and for telephone connections the RJ-11, as well as the RJ-14, which can be used for 2-line telephone connections.
It’s vital to ensure that the connector type is compatible with the device and the network infrastructure it will be used with to ensure proper function and performance.