RJ (Registered Jack) Reference Guide

USOC No. Description Typical Application

RJ11W(Wall)
RJ11C Bridged configurations other than data; single line connections; bridged T/R; 6 position jack Single line non-key telephone, ancillary devices, PBXS and key telephone systems.

RJ12W(Wall)
RJ12C Bridged T/R ahead of the line circuit of a key telephone system with A/A1; 6 position jack. Single line non-key telephone sets and ancillary devices connected to a key system where registered terminal equipment is not compatible with electrical characteristics of tip and ring behind line circuit.

RJ13W(Wall)
RJ13C Bridged T/R behind the line circuit of a key telephone system with A/A1; 6 position jack. Single line non-key telephone sets and ancillary devices connected to a key system.

RJ14W(Wall)
RJ14C Two line bridged T/R; 6 position jack. Two line non-key telephone sets and ancillary devices.

RJ15C Bridged T/R; 3 position weatherproof jack. Providing telephone service to boats in marinas.

RJ16X Bridged tip and ring with mode Indication to A Series Connection ahead of bridged connector; 6 position jack. 9dBM (Data equipment with MI (mode indication) and MIC (mode indication common) leads.

RJ17C Single line bridged tip and ring leads. Tip and ring appear on pins 1 and 6 rather than 3 and 4. Positions 2, 3, 4 and 5 are not equipped with contacts, 6 position jack. Special non-key telephone set or certain hospital ancillary equipment in hospital critical care areas.

RJ18C A bridged connection of single line tip and ring with make-busy leads MB/MB1. 6 position jack. When the registered equipment provides a contact closure between the MB and MBI leads, a make busy indication is transmitted to the network equipment busying out the line from further incoming calls.

RJ19C Bridged tip and ring behind key telephone Line Circuit plus A, A1 and Make Busy Control. 6 position jack. When the registered equipment provides a contact closure between the MB and MBI leads, a make busy indication is transmitted to the network equipment busying out the line from further incoming calls.

RJ21X Multiple line; up to 25 bridged T/R; 50 position jack. Traffic data recording equipment.

RJ22X Multi-line: up to 12 bridged T/R ahead of the line circuit of a key telephone system with A/A1 connection; 50 position jack. 2 to 12 ancillary devices connected to a key system at one location where registered terminal equipment is not compatible with electrical characteristics of tip and ring behind the line circuit.

RJ23X Multi-line: up to 12 bridged T/R behind the line circuit of a key telephone system with A/A1 connections; 50 position jack. 2 to 12 ancillary devices connected to a key system at one location.

RJ24X Multi-line: up to 5 bridged T/R behind the line circuit of a key telephone system. This arrangement has the same wiring arrangement as a standard 5 line key telephone set. Ancillary devices connected to a key system such as 5 line conferencing devices.

RJ2MB Multi-line bridge tip ending with make busy indication. 2 to 12 non-key telephone and ancillary devices connected directly to c.o. lines with make busy requirement.

RJ25C Up to three lines bridged connection 6-position jack. Three line non-key telephone sets, ancillary devices, including message registration, automatic identification, outward dialing, and off-premise station.

RJ26X Data: bridged T/R; 50 position ribbon jack, programmed. Universal jack for fixed loss loop (FLL) or programmed (P) types of data equipment.

RJ27X Bridged T/R; 50 position ribbon jack, programmed. Programmed jack for programmed (P) types of data equipment.

RJ31M Multi-line: up to 8 position series jacks. Multiple series T/R ahead of all station equipment (reference section 68.502 (b)(1).FCC).

RJ31X Series T/R ahead of all station equipment; 8 position series jack. Alarm reporting devices.

RJ32M Multi-line: up to 8 position series jack. Multiple series T/R at station (reference section 68.502 (b)(3).FCC)

RJ32X Series T/R at station; 8 position series jack. Series ancillary devices such as such as automatic dialers. Single line sets with exclusion.

RJ33M Multi-line: up to 8 position series jacks. Multiple series T/R behind the line circuits leading to one key telephone system with A/A1 (reference section 68.502 (b) (3). FCC)

RJ33X Series T/R ahead of the line circuit of a key telephone system with A/A1; 8 position series jack. Series ancillary devices connected to a key system where registered terminal equipment is not compatible with electrical characteristics of tip and ring behind line circuit.

RJ34M Multi-line: up to 8 position series jacks. Multiple series T/R behind the line circuits of a key telephone system with A/A1 (reference section 68.502 (b)(4). FCC)

RJ34X Series T/R behind the line circuit of a key telephone system with A/A1; 8 position series jack. A single line set with exclusion or series ancillary device connected to a key system. This arrangement is preferred to arrangement shown in subsection (b) (3). FCC

RJ35M Multi-line: up to 8 position series jacks. Multiple series T/R behind the line circuits leading to one key telephone station instrument of a key telephone system, with A/A1.

RJ35X Series T/R at key telephone station, behind station pickup key with A/A1; 8 position series jack. Series ancillary devices connected to key telephone set.

RJ36X Series T/R with mode indication signal; 6 position jack. Mode indication (exclusion key) telephone set in series with data jack. Customer shall specify whether a closure or open shall indicate "exclusion" mode.

RJ37X Series T/R on first line and bridged T/R on second line; 8 position series jack. Two line telephones with exclusion on one line.

RJ38X Series connection identical to RJ31X. Strap provides a continuity circuit between 2 and 7, which is used as an indication that the plug of the equipment is engaged with the jack strap provided by telephone company. Registered alarm dialers.

RJ41M Data: multiple bridged T/R; 8 position keyed data jack, universal. Multiple installations of fixed loss loop or programmed types of data equipment.

RJ41S Data: bridged T/R; 8 position keyed data jack, universal. Universal jack for fixed loss loop (FLL) or programmed (P) types of data equipment

RJ42S Data: multiple tip and ring, A and A1. Tip and ring ahead of line circuit; 8 position keyed data jack. Universal jack for FLL or Programmed (P) types of data equipment connected to a key system where the registered terminal equipment is not compatible with electrical characteristics of tip and ring behind the line circuit.

RJ42M Data: multiple tip and ring connected ahead of the line circuit, 8 position keyed data jack. Multiple installations of fixed loss loop or programmed types of data equipment.

RJ43S Data: multiple tip and ring A/A1. Tip and ring behind line circuit; 8 position keyed data jack. Universal jack for FLL or Programmed types of data equipment connected to a key system.

RJ43M Data: multiple tip and ring A/A1 tip and ring behind line circuit; 8 position keyed data jack. Multiple installation of FLL or P data equipment.

RJ45M Data: multiple bridged T/R; 8 position keyed data jack. Multiple installations of programmed types of data equipment.

RJ45S Data: bridged T/R; 8 position keyed data jack, programmed. Programmed data equipment.

RJ46S Data: Single Line bridged tip and ring, A/A1 tip and ring ahead of line circuit; 8 position keyed. Programmed data equipment connected to a key system where the registered terminal equipment is not compatible with electrical characteristics of tip and ring ahead line circuit.

RJ46M Same as RJ46S only in Multiple Mounting arrangements bridged tip and ring with or without A/A1. Programmed data equipment connected to a key system.

RJ47M Data same as RJ47S only in multiple mounting arrangements. Programmed data equipment connected to a key system.

RJ47S Data: single line bridged tip and ring. A/A1 tip and ring behind line circuit; 8 position keyed. Programmed data equipment connected to a key system where the registered terminal equipment is not compatible with electrical characteristics of tip and ring behind line circuit.

RJ48C 8 position digital services jack. Network connection for ISDN terminal equipment using 1.544 Mbps.

RJ48M 50 position miniature ribbon connector for digital services. Multi-line (8 T& R, 8 T1 R1) connections for terminal equipment using 1.544 Mbps.

RJ48S 8 position keyed digital services jack. Network connection for local area data channels and/or sub-rate digital services.

RJ48T 50 position miniature ribbon connector. Multi-line network connection for local area data channels and/or sub-rate digital services.

RJ48X 8 position digital services jack with shorting bars. Network connection for ISDN terminal equipment using 1.544 Mbps.

RJM2X Wall or rack mounting enclosure for use with multiple lines of data and voice blocks and adapters.

RJ51X Data: bridged T/R with A/A1 and Mode Indication; 50 position ribbon jack, universal; T/R connected ahead of the line circuit. Universal jack for fixed loss loop (FLL) or programmed (P) types of data equipment requiring both Mode Indication function and A/A1 connections to a key telephone system. This configuration will normally be used in conjunction with RJ36X series configuration.

RJ52X Data: bridged T/R with A/A1 and Mode Indication; 50 position ribbon jack, programmed; T/R connected ahead of the line circuit. Universal jack for fixed loss loop (FLL) or programmed (p) types of data equipment requiring both Mode Indication function and A/A1 connections to a key telephone system. This configuration will normally be used in conjunction with RJ36X series configuration.

RJ53X Data: bridged T/R with A/A1 and Mode Indication; 50 position ribbon jack, programmed; T/R connected ahead of the line circuit. Programmed jack for programmed (P) types of data equipment requiring both Mode Indication function and A/A1 connections to a key telephone system. This configuration will normally be used in conjunction with RJ36X series configuration.

RJ54X Data: bridged T/R with A/A1 and Mode Indication; 50 position ribbon jack, programmed; T/R connected ahead of the line circuit. Programmed jack for programmed (P) types of data equipment requiring both Mode Indication function and A/A1 connections to a key telephone system. This configuration will normally be used in conjunction with RJ36X series configuration.

RJ71A 8 position jack.

RJ71M 50 pin ribbon jack.

RJA1X Adapter between non-standard square-array 4 pin jack and standard 6 position plug. Single line non-key telephone set or ancillary devices where a working 4 pin jack exists and the registered terminal equipment is equipped with a miniature 6 position plug.

RJA2X Adapters between non-standard square-array 4 pin jack and standard 6 position plug. Single line non-key telephone set or ancillary device where a working miniature 6 position jack exists.

RJA3X Adapter between non-standard 12 pin jack and standard 6 position plug. Single line non-key telephone set or ancillary devices where a working 12 pin jack exists and the registered terminal equipment is equipped with a miniature 6 position plug.

RJA4X Adapter between non-standard rectangular-array 6 pin jack and standard 6 position plug. Single line non-key telephone set or ancillary devices where a working rectangular-array jack exists and the registered terminal equipment is equipped with a miniature 6 position plug.

RJ1DC Single line bridged 4-wire tip/ring and T1/R1. Terminal equipment and systems requiring 4-wire exchange access.

USOC No.	Description	Typical Application
RJ11W(Wall) RJ11C	Bridged configurations other than data; single line connections; bridged T/R; 6 position jack	Single line non-key telephone, ancillary devices, PBXS and key telephone systems.
RJ12W(Wall) RJ12C	Bridged T/R ahead of the line circuit of a key telephone system with A/A1; 6 position jack.	Single line non-key telephone sets and ancillary devices connected to a key system where registered terminal equipment is not compatible with electrical characteristics of tip and ring behind line circuit.
RJ13W(Wall) RJ13C	Bridged T/R behind the line circuit of a key telephone system with A/A1; 6 position jack.	Single line non-key telephone sets and ancillary devices connected to a key system.
RJ14W(Wall) RJ14C	Two line bridged T/R; 6 position jack.	Two line non-key telephone sets and ancillary devices.
RJ15C	Bridged T/R; 3 position weatherproof jack.	Providing telephone service to boats in marinas.
RJ16X	Bridged tip and ring with mode Indication to A Series Connection ahead of bridged connector; 6 position jack.	9dBM (Data equipment with MI (mode indication) and MIC (mode indication common) leads.
RJ17C	Single line bridged tip and ring leads. Tip and ring appear on pins 1 and 6 rather than 3 and 4. Positions 2, 3, 4 and 5 are not equipped with contacts, 6 position jack.	Special non-key telephone set or certain hospital ancillary equipment in hospital critical care areas.
RJ18C	A bridged connection of single line tip and ring with make-busy leads MB/MB1. 6 position jack.	When the registered equipment provides a contact closure between the MB and MBI leads, a make busy indication is transmitted to the network equipment busying out the line from further incoming calls.
RJ19C	Bridged tip and ring behind key telephone Line Circuit plus A, A1 and Make Busy Control. 6 position jack.	When the registered equipment provides a contact closure between the MB and MBI leads, a make busy indication is transmitted to the network equipment busying out the line from further incoming calls.
RJ21X	Multiple line; up to 25 bridged T/R; 50 position jack.	Traffic data recording equipment.
RJ22X	Multi-line: up to 12 bridged T/R ahead of the line circuit of a key telephone system with A/A1 connection; 50 position jack.	2 to 12 ancillary devices connected to a key system at one location where registered terminal equipment is not compatible with electrical characteristics of tip and ring behind the line circuit.
RJ23X	Multi-line: up to 12 bridged T/R behind the line circuit of a key telephone system with A/A1 connections; 50 position jack.	2 to 12 ancillary devices connected to a key system at one location.
RJ24X	Multi-line: up to 5 bridged T/R behind the line circuit of a key telephone system. This arrangement has the same wiring arrangement as a standard 5 line key telephone set.	Ancillary devices connected to a key system such as 5 line conferencing devices.
RJ2MB	Multi-line bridge tip ending with make busy indication.	2 to 12 non-key telephone and ancillary devices connected directly to c.o. lines with make busy requirement.
RJ25C	Up to three lines bridged connection 6-position jack.	Three line non-key telephone sets, ancillary devices, including message registration, automatic identification, outward dialing, and off-premise station.
RJ26X	Data: bridged T/R; 50 position ribbon jack, programmed.	Universal jack for fixed loss loop (FLL) or programmed (P) types of data equipment.
RJ27X	Bridged T/R; 50 position ribbon jack, programmed.	Programmed jack for programmed (P) types of data equipment.
RJ31M	Multi-line: up to 8 position series jacks.	Multiple series T/R ahead of all station equipment (reference section 68.502 (b)(1).FCC).
RJ31X	Series T/R ahead of all station equipment; 8 position series jack.	Alarm reporting devices.
RJ32M	Multi-line: up to 8 position series jack.	Multiple series T/R at station (reference section 68.502 (b)(3).FCC)
RJ32X	Series T/R at station; 8 position series jack.	Series ancillary devices such as such as automatic dialers. Single line sets with exclusion.
RJ33M	Multi-line: up to 8 position series jacks.	Multiple series T/R behind the line circuits leading to one key telephone system with A/A1 (reference section 68.502 (b) (3). FCC)
RJ33X	Series T/R ahead of the line circuit of a key telephone system with A/A1; 8 position series jack.	Series ancillary devices connected to a key system where registered terminal equipment is not compatible with electrical characteristics of tip and ring behind line circuit.
RJ34M	Multi-line: up to 8 position series jacks.	Multiple series T/R behind the line circuits of a key telephone system with A/A1 (reference section 68.502 (b)(4). FCC)
RJ34X	Series T/R behind the line circuit of a key telephone system with A/A1; 8 position series jack.	A single line set with exclusion or series ancillary device connected to a key system. This arrangement is preferred to arrangement shown in subsection (b) (3). FCC
RJ35M	Multi-line: up to 8 position series jacks.	Multiple series T/R behind the line circuits leading to one key telephone station instrument of a key telephone system, with A/A1.
RJ35X	Series T/R at key telephone station, behind station pickup key with A/A1; 8 position series jack.	Series ancillary devices connected to key telephone set.
RJ36X	Series T/R with mode indication signal; 6 position jack.	Mode indication (exclusion key) telephone set in series with data jack. Customer shall specify whether a closure or open shall indicate "exclusion" mode.
RJ37X	Series T/R on first line and bridged T/R on second line; 8 position series jack.	Two line telephones with exclusion on one line.
RJ38X	Series connection identical to RJ31X. Strap provides a continuity circuit between 2 and 7, which is used as an indication that the plug of the equipment is engaged with the jack strap provided by telephone company.	Registered alarm dialers.
RJ41M	Data: multiple bridged T/R; 8 position keyed data jack, universal.	Multiple installations of fixed loss loop or programmed types of data equipment.
RJ41S	Data: bridged T/R; 8 position keyed data jack, universal.	Universal jack for fixed loss loop (FLL) or programmed (P) types of data equipment
RJ42S	Data: multiple tip and ring, A and A1. Tip and ring ahead of line circuit; 8 position keyed data jack.	Universal jack for FLL or Programmed (P) types of data equipment connected to a key system where the registered terminal equipment is not compatible with electrical characteristics of tip and ring behind the line circuit.
RJ42M	Data: multiple tip and ring connected ahead of the line circuit, 8 position keyed data jack.	Multiple installations of fixed loss loop or programmed types of data equipment.
RJ43S	Data: multiple tip and ring A/A1. Tip and ring behind line circuit; 8 position keyed data jack.	Universal jack for FLL or Programmed types of data equipment connected to a key system.
RJ43M	Data: multiple tip and ring A/A1 tip and ring behind line circuit; 8 position keyed data jack.	Multiple installation of FLL or P data equipment.
RJ45M	Data: multiple bridged T/R; 8 position keyed data jack.	Multiple installations of programmed types of data equipment.
RJ45S	Data: bridged T/R; 8 position keyed data jack, programmed.	Programmed data equipment.
RJ46S	Data: Single Line bridged tip and ring, A/A1 tip and ring ahead of line circuit; 8 position keyed.	Programmed data equipment connected to a key system where the registered terminal equipment is not compatible with electrical characteristics of tip and ring ahead line circuit.
RJ46M	Same as RJ46S only in Multiple Mounting arrangements bridged tip and ring with or without A/A1.	Programmed data equipment connected to a key system.
RJ47M	Data same as RJ47S only in multiple mounting arrangements.	Programmed data equipment connected to a key system.
RJ47S	Data: single line bridged tip and ring. A/A1 tip and ring behind line circuit; 8 position keyed.	Programmed data equipment connected to a key system where the registered terminal equipment is not compatible with electrical characteristics of tip and ring behind line circuit.
RJ48C	8 position digital services jack.	Network connection for ISDN terminal equipment using 1.544 Mbps.
RJ48M	50 position miniature ribbon connector for digital services.	Multi-line (8 T& R, 8 T1 R1) connections for terminal equipment using 1.544 Mbps.
RJ48S	8 position keyed digital services jack.	Network connection for local area data channels and/or sub-rate digital services.
RJ48T	50 position miniature ribbon connector.	Multi-line network connection for local area data channels and/or sub-rate digital services.
RJ48X	8 position digital services jack with shorting bars.	Network connection for ISDN terminal equipment using 1.544 Mbps.
RJM2X	Wall or rack mounting enclosure for use with multiple lines of data and voice blocks and adapters.
RJ51X	Data: bridged T/R with A/A1 and Mode Indication; 50 position ribbon jack, universal; T/R connected ahead of the line circuit.	Universal jack for fixed loss loop (FLL) or programmed (P) types of data equipment requiring both Mode Indication function and A/A1 connections to a key telephone system. This configuration will normally be used in conjunction with RJ36X series configuration.
RJ52X	Data: bridged T/R with A/A1 and Mode Indication; 50 position ribbon jack, programmed; T/R connected ahead of the line circuit.	Universal jack for fixed loss loop (FLL) or programmed (p) types of data equipment requiring both Mode Indication function and A/A1 connections to a key telephone system. This configuration will normally be used in conjunction with RJ36X series configuration.
RJ53X	Data: bridged T/R with A/A1 and Mode Indication; 50 position ribbon jack, programmed; T/R connected ahead of the line circuit.	Programmed jack for programmed (P) types of data equipment requiring both Mode Indication function and A/A1 connections to a key telephone system. This configuration will normally be used in conjunction with RJ36X series configuration.
RJ54X	Data: bridged T/R with A/A1 and Mode Indication; 50 position ribbon jack, programmed; T/R connected ahead of the line circuit.	Programmed jack for programmed (P) types of data equipment requiring both Mode Indication function and A/A1 connections to a key telephone system. This configuration will normally be used in conjunction with RJ36X series configuration.
RJ71A	8 position jack.
RJ71M	50 pin ribbon jack.
RJA1X	Adapter between non-standard square-array 4 pin jack and standard 6 position plug.	Single line non-key telephone set or ancillary devices where a working 4 pin jack exists and the registered terminal equipment is equipped with a miniature 6 position plug.
RJA2X	Adapters between non-standard square-array 4 pin jack and standard 6 position plug.	Single line non-key telephone set or ancillary device where a working miniature 6 position jack exists.
RJA3X	Adapter between non-standard 12 pin jack and standard 6 position plug.	Single line non-key telephone set or ancillary devices where a working 12 pin jack exists and the registered terminal equipment is equipped with a miniature 6 position plug.
RJA4X	Adapter between non-standard rectangular-array 6 pin jack and standard 6 position plug.	Single line non-key telephone set or ancillary devices where a working rectangular-array jack exists and the registered terminal equipment is equipped with a miniature 6 position plug.
RJ1DC	Single line bridged 4-wire tip/ring and T1/R1.	Terminal equipment and systems requiring 4-wire exchange access.