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RJ Registered Jack

In data communications, the acronym RJ stands for Registered Jack. Registered Jacks are electrical connector designs registered with the Federal Communications Commission (FCC). A number is added to the RJ designation (RJ-##) to further identify the connector. RJ connectors are typically used with twisted pair wiring. RJ-11, RJ-12 and RJ-14 are the most common 4-conductor and 6-conductor connectors and the RJ-45 is the most common 8-conductor connector. Most often these connectors are used for telephone wiring and LAN wiring. They were originally invented and patented by Bell Telephone Laboratories in the 1970s and went on to essentially replace hard-wired connections. There is some naming convention and physical compatibility confusion when referring to the 4 and 6 conductor (or pin) jacks. Even the FCC commonly refers to all of these jacks as 6-pin connectors, however the RJ-11 is a 4-pin plug. The confusion most likely is a result of design compatibility as smaller connector jacks can often fit larger sockets, yet only connect to the center conductors. Always be sure your connectors and sockets are compatible before installation. Some manufacturers explicitly warn that placing smaller connectors in larger sockets can cause damage. If you have any questions about these connectors or any of our products, a Falcon Tech rep is always ready and willing to help!