The registered jack designations originated in the standardization process of telephone connections in the Bell System in the United States, and describe application circuits and not just the physical geometry … See more

Registration interfaces were created by the Bell System under a Federal Communications Commission order for the standard interconnection between telephone company … See more

All of these registered jacks are described as containing a number of potential contact positions and the actual number of contacts installed within these positions. RJ11, RJ14, and … See more

The RJ45S, an obsolete standard jack once specified for modem or data interfaces, has a slot on one side to allow mating with a special … See more

The most widely implemented registered jack in telecommunications is the RJ11. This is a modular connector wired for one telephone line, using the center two contacts of six available positions. This configuration is also used for single-line telephones in many … See more

RJ21 is a registered jack standard using a micro ribbon connector with contacts for up to fifty conductors. It is used to implement connections for … See more

RJ48 is used for T1 and ISDN termination, local-area data channels, and subrate digital services. It uses the eight-position See more