Registered jack - AbsoluteAstronomy.com

A registered jack is a standardized physical network interface

Network interface

Network interface may refer to:* Network interface controller, the device a computer uses to connect to a computer network* Network interface device, a demarcation point for a telephone network...

— both jack construction and wiring pattern — for connecting telecommunications or data equipment to a service provided by a local exchange carrier

Local exchange carrier

Local Exchange Carrier is a regulatory term in telecommunications for the local telephone company.In the United States, wireline telephone companies are divided into two large categories: long distance and local...

or long distance carrier. The standard designs for these connectors and their wiring are named RJ11, RJ14, RJ21, RJ48, etc. Many of these interface standards are commonly used in North America, though some interfaces are used world-wide.

The physical connectors that registered jacks use are mainly of the modular connector

Modular connector

Modular connector is the name given to a family of electrical connectors originally used in telephone wiring and now used for many other purposes. Many applications that originally used a bulkier, more expensive connector have now migrated to modular connectors...

and 50-pin miniature ribbon

Micro ribbon

The micro ribbon or miniature ribbon connector is a common type of electrical connector used particularly in computer and telecommunications applications. Popularly referred to as a Centronics connector due to the widely used Centronics parallel interface, it is also known as a Telco, Amphenol,...

connector types. For example, RJ11 uses a 6 position 2 conductor (6P2C) modular plug and jack, while RJ21 uses a 50-pin miniature ribbon connector.

Naming confusion

The registered jack designation describes a wiring pattern and not just the physical geometry of the connectors; inspection of the connector will not necessarily show which registered jack wiring pattern is used. The same modular connector type can be used for different registered jack connections.

Strictly, registered jack refers to both the female physical connector (modular connector

Modular connector

) and its wiring, but the term is often used loosely to refer to modular connectors regardless of wiring or gender, such as in Ethernet over twisted pair

Ethernet over twisted pair

Ethernet over twisted pair technologies use twisted-pair cables for the physical layer of an Ethernet computer network. Other Ethernet cable standards employ coaxial cable or optical fiber. Early versions developed in the 1980s included StarLAN followed by 10BASE-T. By the 1990s, fast, inexpensive...

. There is much confusion over these connection standards. The six-position plug and jack commonly used for telephone line connections may be used for RJ11, RJ14 or even RJ25, all of which are actually names of interface standards that use this physical connector. The RJ11 standard dictates a 2-wire connection, while RJ14 uses a 4-wire configuration, and RJ25 uses all six wires. The RJ abbreviations, though, only pertain to the wiring of the jack (hence the name registered jack); it is commonplace but not strictly correct to refer to an unwired plug connector by any of these names.

Modular connectors were a development from the older telephone connectors

Telephone plug

A telephone plug is a type of male connector used to connect a telephone to the telephone wiring in a home or business, and in turn to a local telephone network. It is inserted into its female counterpart, a telephone "jack", commonly affixed to a wall or baseboard...

, which were very bulky or wired directly to the wall and therefore not accommodating of modular systems. The common nomenclature for modular connectors gives the number of contact positions and the number of wires connected, for example 6P indicate a six-position modular plug or jack. A six-position modular plug with conductors in the middle two positions and the other four positions unused is called a 6P2C. RJ11 uses a 6P2C. The connectors could be supplied with more pins, but if more pins are actually wired, the interface is no longer an RJ11.

Twisted pair

While the plugs are generally used with a flat cable (a notable exception being Ethernet twisted-pair cabling used with the 8P8C modular plug), the long cables feeding them in the building wiring and the phone network before them normally consist of twisted pair

Twisted pair

Twisted pair cabling is a type of wiring in which two conductors are twisted together for the purposes of canceling out electromagnetic interference from external sources; for instance, electromagnetic radiation from unshielded twisted pair cables, and crosstalk between neighboring pairs...

s of wires. Wiring conventions were designed to take full advantage of the physical compatibility ensuring that using a smaller plug in a larger socket would pick up complete pairs not a (relatively useless) two half pairs but here again there has been a problem. The original concept was that the centre two pins would be one pair, the next two out the second pair, and so on until the outer pins of an eight-pin connector would be the fourth twisted pair. Additionally, signal shielding was optimised by alternating the live (hot) and earthy (ground) pins of each pair. This standard for the eight-pin connector is the USOC-defined pinout, but the outermost pair are then too far apart to meet the electrical requirements of high-speed LAN protocols. Two variations known as T568A and T568B overcome this by using adjacent pairs of the outer four pins for the third and fourth pairs. For T568A, the inner four pins are wired identically to those in RJ14. In the T568B variant, different pairs are assigned to different pins, so a T568B jack is incompatible with the wiring pattern of RJ14. In connecting cables, however, the performance differences between the pairs that are assigned to different pins are minimal, and in general use T568A and T568B patch cable

Patch cable

A patch cable or patch cord is an electrical or optical cable used to connect one electronic or optical device to another for signal routing. Devices of different types are connected with patch cords...

s are interchangeable.

History and authority

Registered jacks were created by industry and regulated by the FCC

Federal Communications Commission

The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the...

to be the standard interface between a telephone company and a customer. The wired communications provider (telephone company) is responsible for delivery of services to a minimum point of entry (MPOE) (physically a utility box) which connects the telephone/network wiring on the customer's property (customer-premises equipment

Customer-premises equipment

Customer-premises equipment or customer-provided equipment is any terminal and associated equipment located at a subscriber's premises and connected with a carrier's telecommunication channel at the demarcation point...

/CPE) to the communication provider's network. The customer is responsible for jacks, wiring, and equipment on their side of the MPOE. The intent is to establish a universal standard for wiring and interfaces, and to separate ownership of in-home (or in-office) telephone wiring away from the wiring owned by the telephone company.

Under the Bell System

Bell System

The Bell System was the American Bell Telephone Company and then, subsequently, AT&T led system which provided telephone services to much of the United States and Canada from 1877 to 1984, at various times as a monopoly. In 1984, the company was broken up into separate companies, by a U.S...

monopoly (following the Communications Act of 1934

Communications Act of 1934

The Communications Act of 1934 is a United States federal law, enacted as Public Law Number 416, Act of June 19, 1934, ch. 652, 48 Stat. 1064, by the 73rd Congress, signed by President Franklin D. Roosevelt, codified as Chapter 5 of Title 47 of the United States Code, et seq. The Act replaced the...

),
the Bell System owned the phones and did not allow interconnection

Interconnection

In telecommunications, interconnection is the physical linking of a carrier's network with equipment or facilities not belonging to that network...

of separate phones or other terminal equipment

Terminal equipment

In telecommunication, the term terminal equipment has the following meanings:* Communications equipment at either end of a communications link, used to permit the stations involved to accomplish the mission for which the link was established....

. Phones were generally hardwired, or at times used proprietary Bell System connectors.

This began to change with the case Hush-A-Phone v. United States [1956] and the FCC

Federal Communications Commission

's Carterfone
Carterfone
The Carterfone is a device invented by Thomas Carter. It manually connects a two-way mobile radio system to the public switched telephone network , making it a direct predecessor to today's autopatch....

[1968] decision, which required Bell to allow some interconnection, which culminated in registered jacks.

Registered jacks were introduced by the Bell System in the 1970s under a 1976 FCC order ending the use of protective couplers. They replaced earlier, bulkier connectors. The Bell System issued specifications for the modular connectors and their wiring as Universal Service Order Codes, (USOC), which were the only standard at the time. USOCs are commonly passed to the communications provider by large businesses for a variety of services. Because there are many standardized interface options available to the customer, the customer must specify the type of interface required by RJ/USOC. For a multi-line interface such as the RJ21, they must denote which position(s) of the interface are to be used. If there are multiple RJ21 connectors, they are numbered sequentially and the customer must advise the communications provider of which one to use.

When the US telephone industry was opened to more competition in the 1980s, the specifications became US law, ordered by the Federal Communications Commission

Federal Communications Commission

(FCC) and codified in the Code of Federal Regulations, Title 47 CFR Part 68, Subpart F superseded by T1.TR5-1999.

In January 2001, the FCC delegated responsibility for standardizing connections to the telephone network to a new private industry organization, the Administrative Council for Terminal Attachments (ACTA). The FCC removed Subpart F from the CFR and added Subpart G, which delegates the task to the ACTA. The ACTA published a standard called TIA/EIA-IS-968 which contained the information that was formerly in the CFR. The current version of that standard, called TIA-968-A, specifies the modular connectors at length, but not the wiring. Instead, TIA-968-A incorporates a standard called T1.TR5-1999, "Network and Customer Installation Interface Connector Wiring Configuration Catalog", by reference to specify the wiring. With the publication of TIA-968-B, the connector descriptions have been moved to TIA-1096-A. Note that a registered jack name such as RJ11 identifies both the physical connectors and the wiring (pinout) of it (see above).

International use

The modular jack was chosen as a candidate for ISDN systems. In order to be considered, the connector system had to be defined under international standards. In turn this led to ISO 8877. Under the rules of the IEEE 802

IEEE 802

IEEE 802 refers to a family of IEEE standards dealing with local area networks and metropolitan area networks.More specifically, the IEEE 802 standards are restricted to networks carrying variable-size packets. IEEE 802 refers to a family of IEEE standards dealing with local area networks and...

standards project, international standards are to be preferred over national standards so the modular connector was chosen for IEEE 802.3i-1990, the original 10BASE-T

10BASE-T

twisted-pair wiring version of Ethernet

Ethernet

Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....

Common types

The most familiar registered jack is probably the RJ11. This is a modular connector wired for one plain old telephone service

Plain old telephone service

Plain old telephone service is the voice-grade telephone service that remains the basic form of residential and small business service connection to the telephone network in many parts of the world....

line (using two wires out of six available positions), and is found in most homes and offices in most countries of the world for single-line telephones. Essentially all one, two, and three line analog telephones made today (2009) are meant to plug into RJ11, RJ14, or RJ25 jacks, respectively.

RJ14 is similar, but for two lines, and RJ25 is for three lines. RJ61 is a similar registered jack for four lines. The telephone line cord and its plug are more often a true RJ11 with only two conductors.

The true RJ45(S) is an extremely uncommon registered jack, but the name RJ45 is also used quite commonly to refer to any 8P8C modular connector.

List of official registered jacks

Code	Connector	Usage
RJ2MB	50-pin miniature ribbon	2–12 telephone lines with make-busy arrangement
RJ11C/RJ11W	6P2C	For one telephone line (6P4C if power on second pair)
RJ12C/RJ12W	6P6C	For one telephone line ahead of the key system Key telephone system A business telephone system is any of a range of a multiline telephone systems typically used in business environments, encompassing systems ranging from small key systems to large scale private branch....
RJ13C/RJ13W	6P4C	For one telephone line behind the key system Key telephone system A business telephone system is any of a range of a multiline telephone systems typically used in business environments, encompassing systems ranging from small key systems to large scale private branch....
RJ14C/RJ14W	6P4C	For two telephone lines (6P6C if power on third pair)
RJ15C	3-pin weatherproof	For one telephone line
RJ18C/RJ18W	6P6C	For one telephone line with make-busy arrangement
RJ21X	50-pin miniature ribbon	For up to 25 lines
RJ25C/RJ25W	6P6C	For three telephone lines
RJ26X	50-pin miniature ribbon	For multiple data lines, universal
RJ27X	50-pin miniature ribbon	For multiple data lines, programmed
RJ31X	8P8C	Allows an alarm system to seize the telephone line to make an outgoing call during an alarm. Jack is placed ahead of all other equipment. (Only 4C are actually used)
RJ38X	8P8C	Similar to RJ31X, with continuity circuit. If the plug is disconnected from the jack shorting bars allows the phone circuit to continue to the site phones. (Only 4C are actually used)
RJ41S	8P8C, keyed	For one data line, universal (fixed loop loss and programed)
RJ45S	8P8C, keyed	For one data line, with programming resistor
RJ48C	8P8C	For four-wire data line (DSX-1)
RJ48S	8P8C	For four-wire data line (DDS)
RJ48X	8P8C with shorting bar	For four-wire data line (DS1)
RJ49C	8P8C	For ISDN BRI via NT1
RJ61X	8P8C	For four telephone lines
RJ71C	50-pin miniature ribbon	12 line series connection using 50 pin connector (with bridging adapter) ahead of customer equipment. Mostly used for call sequencer equipment.

Many of the basic names have suffixes that indicate subtypes:

C: flush-mount or surface mount
F: flex-mount
W: wall-mount
L: lamp-mount
S: single-line
M: multi-line
X: complex jack

For example, RJ11 comes in two forms: RJ11W is a jack from which you can hang a wall telephone, while RJ11C is a jack designed to have a cord plugged into it. (You can plug a cord into an RJ11W as well, but it usually does not look as nice as a cord plugged into an RJ11C.)

Unofficial plug names

These RJ names do not refer to official ACTA RJ types:

RJ9, RJ10, RJ22: 4P4C or 4P2C, for telephone handsets. Since telephone handsets do not connect directly to the public network, they have no registered jack code whatsoever.
RJ45: 8P8C, informal designation for T568A/T568B, including Ethernet; not the same as the true RJ45/RJ45S
RJ50: 10P10C, often used for data

RJ11, RJ14, RJ25 wiring details

All of these registered jacks are described as containing a number of potential contact

Electrical connector

An electrical connector is an electro-mechanical device for joining electrical circuits as an interface using a mechanical assembly. The connection may be temporary, as for portable equipment, require a tool for assembly and removal, or serve as a permanent electrical joint between two wires or...

positions and the actual number of contacts installed within these positions. RJ11, RJ14, and RJ25 all use the same six-position modular connector

Modular connector

, thus are physically identical except for the different number of contacts (two, four and six respectively) allowing connections for 1, 2 or 3 phone lines respectively.

Cables sold as RJ11 often actually use 6P4C RJ14 connectors (six position, four conductor), with four wires running to a central junction box. Two of its six possible contact positions connect tip and ring, and the other two conductors are then unused. 6P2C and 6P6C can also be found in stores.

The conductors other than the two central tip and ring conductors are in practice used for various things such as a second or third phone line, a ground

Ground (electricity)

In electrical engineering, ground or earth may be the reference point in an electrical circuit from which other voltages are measured, or a common return path for electric current, or a direct physical connection to the Earth....

for selective ringers

Party line (telephony)

In twentieth-century telephone systems, a party line is an arrangement in which two or more customers are connected directly to the same local loop. Prior to World War II in the United States, party lines were the primary way residential subscribers acquired local telephone service...

, low voltage power for a dial light, or for 'anti-tinkle' circuitry to prevent pulse dialing

Pulse dialing

Pulse dialing, dial pulse, or loop disconnect dialing, also called rotary or decadic dialling in the United Kingdom , is pulsing in which a direct-current pulse train is produced by interrupting a steady signal according to a fixed or formatted code for each digit and at a standard pulse repetition...

phones from ringing the bell on other extensions. With tone dialing anti-tinkle measures are not required.

Pinouts

Holding the connector in your hand tab side down with the cable opening toward you, the pins are numbered 1–6, left to right.


Position	Pair	T/R Tip and ring "Tip" and "Ring" are common terms in the telephone service industry referring to the two wires or sides of an ordinary telephone line. Tip is the ground side and Ring is the battery side of a phone circuit. In the UK these are referred to as the 'A' and 'B' wires...	±	RJ11	RJ14	RJ25	25-pair color code 25-pair color code The 25-pair color code is a color code used to identify individual conductors in a kind of electrical telecommunication wiring for indoor use, known as twisted pair cables . The colors are applied to the insulation that covers each conductor...			Australian colors
1	3	T	+			T3	white/green	white	violet	orange
2	2	T	+		T2	T2	white/orange	black	green	red
3	1	R	-	R1	R1	R1	blue/white	red	white	blue
4	1	T	+	T1	T1	T1	white/blue	green	brown	white
5	2	R	-		R2	R2	orange/white	yellow	yellow	black
6	3	R	-			R3	green/white	blue	slate	green

While the old solid color code was well established for pair 1 and usually pair 2, there are several conflicting conventions for pair 3 (and sometimes even pair 2). The colors shown above were taken from a vendor of "silver satin" flat 8-conductor phone cable that claims to be standard. 6-pair solid (old) bellwire cables previously used by the Bell System

Bell System

use white for pair 3 tip but some vendor's cable may substitute orange for white. At least one other vendor of flat 8-conductor cable uses the sequence blue, orange, black, red, green, yellow, brown and white/slate. This color scheme originates in the (withdrawn) national standard DIN 47100

DIN 47100

The German DIN Standard DIN 47100 regulated the color coding for the identification of cores in telecommunication cables. The standard was withdrawn without a replacement in November 1998, but remains in widespread use by cable manufacturers....

. The scheme shown here is the correct color code for interfacing with the RJ connector standards.

However, with German domestic telephone equipment (and that in some neighbouring countries), 6P4C plugs and sockets are typically only used to connect the telephone cable to the phone base unit, whereas the mechanically different TAE plug

TAE connector

TAE is the German standard for telephone plugs and sockets....

is used at the other end of the cable. Older base units may accommodate the additional connectors of TAE (E, W, a2, b2) and may feature non-RJ standard sockets that can be connected „straight“ to TAE plugs. Further, flat DIN 47100 cables typically place the wires in ascending order. When used directly with 6P4C plugs, the colors will be garbled.

Powered version of RJ11

In the powered version, Pins 2 and 5 (black and yellow) may carry low voltage AC or DC power. While the phone line itself (tip and ring) supplies enough power for most telephone terminals, old telephone terminals with incandescent lights in them (such as the classic Western Electric Princess

Princess telephone

The Princess Phone was introduced by the Bell System in 1959. It was a compact telephone designed for convenient use in the bedroom, and contained a light-up dial for use as a night-light. It was commonly known with the slogan "It's little...It's lovely...It lights", which was suggested Robert Karl...

and Trimline telephone

Trimline telephone

The Western Electric Trimline telephone is a variety of telephone set designed by Donald Genaro of Henry Dreyfuss Associates for the Bell System . It was built by the Bell System's manufacturing arm, Western Electric. The idea behind the Trimline telephone was to create an alternative telephone...

s) need more power than the phone line can supply. Typically, the power on Pins 2 and 5 comes from a transformer

Transformer

A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...

plugged into a power outlet near one jack, supplying power to all of the jacks in the house. Trimline and Princess phone dial lights are rated at 6.3 volts and the transformer output is approximately 5 volts, providing a long service life for the incandescent lamps.

Compatibility with structured cabling

With the rise of Ethernet

Ethernet

local area network

Local area network

A local area network is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building...

s operating over Cat5e

Category 5 cable

Category 5 cable is a twisted pair cable for carrying signals. This type of cable is used in structured cabling for computer networks such as Ethernet. It is also used to carry other signals such as telephony and video. The cable is commonly connected using punch down blocks and modular connectors...

and Cat6

Category 6 cable

Category 6 cable, commonly referred to as Cat 6, is a cable standard for Gigabit Ethernet and other network physical layers that is backward compatible with the Category 5/5e and Category 3 cable standards. Compared with Cat 5 and Cat 5e, Cat 6 features more stringent specifications for crosstalk...

unshielded twisted pair

Twisted pair

cable, structured cabling

Structured cabling

Structured cabling is building or campus telecommunications cabling infrastructure that consists of a number of standardized smaller elements called subsystems.Structured cabling falls into six subsystems:...

networks adhering to TIA/EIA-568-B are widely used for both computer networking and analog telephony. The 8P8C (RJ45) jack used by TIA/EIA-568-B physically accepts the 6-position connector used by RJ11, RJ14 and RJ25, but only RJ11 and RJ14 have full electrical compatibility. TIA/EIA-568-B splits the third pair of RJ25 across two separate cable pairs, rendering it unusable. This was necessary to preserve the electrical properties of those pairs for Ethernet, which operates at much higher frequencies than analog telephony.

Both the third and fourth pairs of RJ61 are similarly split. Because of this incompatibility, and because they were never very common to begin with, the TIA/EIA-568-B conventions are displacing RJ25 and RJ61 for telephones with more than two lines.

Although a 4-pin and 6-pin connector will fit into the 8-pin jack, the smaller connector can potentially damage the contacts of the larger, because the outside edges of the smaller connector press onto the contacts of the larger. The outside edges of an RJ11/RJ45 typically project out by about 0.5 to 1.0 mm further than the contact surfaces, and these edges press the contacts of the larger connecter further than if a full-size connector were plugged in. The smaller connector may therefore permanently bend pins 1,8 or 2,7 of the larger connector.

RJ21

RJ21 is a registered jack standard

Standardization

Standardization is the process of developing and implementing technical standards.The goals of standardization can be to help with independence of single suppliers , compatibility, interoperability, safety, repeatability, or quality....

for a modular connector

Modular connector

using 50 conductors, usually used to implement a 25-line

Telephone line

A telephone line or telephone circuit is a single-user circuit on a telephone communication system...

(or less) telephone

Telephone

The telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...

connection such as that used in the 1A2 key telephone system

1A2 Key System

The 1A2 Key System is an analog multiline business key telephone system. Unlike more modern multiline systems, every telephone line serving a particular phone is wired into that phone, and electromechanical switches switch the lines in the phone itself...

. It is also known as a 50-pin telco connector, CHAMP(AMP) or an Amphenol connector. (The latter is a genericized trademark

Genericized trademark

A genericized trademark is a trademark or brand name that has become the colloquial or generic description for, or synonymous with, a general class of product or service, rather than as an indicator of source or affiliation as intended by the trademark's holder...

, as Amphenol

Amphenol

Amphenol Corporation is a major producer of electronic and fiber optic connectors, cable and interconnect systems such as Coaxial cables. Amphenol is a portmanteau from the corporation's original name, American Phenolic Corp....

was the largest manufacturer of these at one time.)

Dual RJ21 connectors are often used on punch block

Punch block

A punch down block is a type of electrical connection often used in telephony. It is named because the solid copper wires are "punched down" into short open-ended slots which are a type of insulation-displacement connectors...

s to make a breakout box

Breakout box

A breakout box is an electrical device, usually housed in a box, in which a compound electrical connector is separated or "broken out" into its component connectors. Compound connectors are used where sufficient space for connections is unavailable...

for PBX and other key telephone system

Key telephone system

A business telephone system is any of a range of a multiline telephone systems typically used in business environments, encompassing systems ranging from small key systems to large scale private branch....

s.

RJ21 connectors are used to connect Ethernet

Ethernet

ports in bulk from a switch with RJ21 ports to a CAT-5 rated patch panel

Patch panel

A patch panel or patch bay is a panel, typically rackmounted, that houses cable connections. One typically shorter patch cable will plug into the front side, whereas the back holds the connection of a much longer and more permanent cable...

, or between two patch panels. A cable with an RJ21 connector on one end can support 6 fully wired 8P8C connectors or Ethernet ports on a patch panel with 1 spare pair. Alternatively, only the necessary pairs for 10/100 Ethernet can be wired allowing 12 Ethernet ports with a single spare pair.

The same connector (with spring bail locks) is used for SCSI-1 connections. Some computer printer

Computer printer

In computing, a printer is a peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a...

s use a shorter 36-pin version known as a Centronics connector.

A cable color scheme, in common use, is determined for 25 pairs of conductors as follows: For each ring, the primary, more prominent color is chosen from {blue, orange, green, brown, slate}, in that order, and the secondary, thinner stripe color from {white, red, black, yellow, violet}, in that order. The tip conductor color scheme uses the same colors as the matching ring but switches the thickness of the primary and secondary colored stripes. Since the sets are ordered, an orange (color 2 in its set) with a yellow (color 4) is the color scheme for the 4·5 + 2 − 5 = 17th pair of wires. If the yellow is the more prominent, thicker stripe, then the wire is a tip conductor connecting to the pin numbered 25 + the pair #, which is pin 42 in this case. (Ring conductors connect to the same pin number as the pair number.)

A conventional enumeration of wire color pairs then begins blue (& white), orange (& white), green (& white) and brown (& white), which subsumes a color coding convention used in cables of 4 or fewer pairs (8 wires or less) with 8P and 6P connectors.

Color	Pin (Tip)	Pin (Ring)	Color
White/Blue	26	1	Blue/White
White/Orange	27	2	Orange/White
White/Green	28	3	Green/White
White/Brown	29	4	Brown/White
White/Slate	30	5	Slate/White
Red/Blue	31	6	Blue/Red
Red/Orange	32	7	Orange/Red
Red/Green	33	8	Green/Red
Red/Brown	34	9	Brown/Red
Red/Slate	35	10	Slate/Red
Black/Blue	36	11	Blue/Black
Black/Orange	37	12	Orange/Black
Black/Green	38	13	Green/Black
Black/Brown	39	14	Brown/Black
Black/Slate	40	15	Slate/Black
Yellow/Blue	41	16	Blue/Yellow
Yellow/Orange	42	17	Orange/Yellow
Yellow/Green	43	18	Green/Yellow
Yellow/Brown	44	19	Brown/Yellow
Yellow/Slate	45	20	Slate/Yellow
Violet/Blue	46	21	Blue/Violet
Violet/Orange	47	22	Orange/Violet
Violet/Green	48	23	Green/Violet
Violet/Brown	49	24	Brown/Violet
Violet/Slate	50	25	Slate/Violet

RJ45

RJ45 is a registered jack standard for a modular connector using 8 conductors, which specifies the physical male and female connectors as well as the pin assignments of the wires in a telephone cable. The "RJ45" physical connector is standardised as the IEC 60603-7 8P8C modular connector with different "categories" of performance, with all eight conductors present but 8P8C is commonly known as RJ45. The physical dimensions of the connectors are specified in ANSI/TIA-1096-A and ISO-8877 standards.

A similar standard jack once used for modem/data connections, the RJ45S, uses a "keyed" variety of the 8P body with an extra tab that prevents it mating with other connectors; the visual difference compared to the more common 8P8C is subtle but is a different connector. The original RJ45S used a special keyed 8P2C modular connector, with pins 5 and 4 wired for tip and ring of a single telephone line and pins 7 and 8 shorting a programming resistor, but is obsolete today.

Electronics catalogs commonly advertise 8P8C modular connectors as "RJ45", but of course an installer can wire the jack to any pin-out or use it as part of a generic structured cabling

Structured cabling

system such as ISO/IEC 15018 or ISO/IEC 11801

ISO/IEC 11801

International standard ISO/IEC 11801 specifies general-purpose telecommunication cabling systems that are suitable for a wide range of applications . It covers both balanced copper cabling and optical fibre cabling...

using RJ45 patch panels for both phone and data. Virtually all electronic equipment which uses an 8P8C connector (or possibly any 8P connector at all) will document it as an "RJ45" connector.

Crossover Cables

A router to router crossover cable uses two 8 position connectors and a UTP (Unshielded Twisted Pair) cable with differently wired connectors at each end. Despite the fact that a registered jack simply identifies a form factor rather than a pinout, crossover cables are often incorrectly marketed as "RJ45 crossover cables". RJ45 is only a form factor, so the RJ45 designation should never be used to describe a wiring pattern.

RJ48

RJ48 is a registered jack. It is used for T1

Digital Signal 1

Digital signal 1 is a T-carrier signaling scheme devised by Bell Labs. DS1 is a widely used standard in telecommunications in North America and Japan to transmit voice and data between devices. E1 is used in place of T1 outside North America, Japan, and South Korea...

and ISDN termination and local area data channels/subrate digital services. It uses the 8 position modular connector

Modular connector

.

RJ48C is commonly used for T1

Digital Signal 1

lines and uses pins 1, 2, 4 and 5.

RJ48X is a variation of RJ48C that contains shorting blocks in the jack so that a loopback is created for troubleshooting when unplugged by connecting pins 1 and 4, and 2 and 5. Sometimes this is referred to as a "smart jack".

RJ48S is typically used for local area data channels/subrate digital services, and carries one or two lines. It uses a keyed variety of the 8P8C modular connector

Modular connector

.

RJ48 connectors are fastened to STP (shielded twisted pair) cables, not the standard UTP (unshielded twisted pair) CAT-(1-5).

RJ48C and RJ48X wiring
Pin	Pair	Signal	\| Color
1	R	RX Ring	Orange/White
2	T	RX Tip	White/Orange
3		reserved	White/Green
4	R1	TX Ring	Blue/White
5	T1	TX Tip	White/Blue
6		reserved	Green/White
7		shield	White/Brown
8		shield	Brown/White

RJ61

RJ61 is a physical interface

Electrical connector

often used for terminating twisted pair

Twisted pair

type cables. It is one of the Registered Jack

Registered jack

A registered jack is a standardized physical network interface — both jack construction and wiring pattern — for connecting telecommunications or data equipment to a service provided by a local exchange carrier or long distance carrier. The standard designs for these connectors and their wiring...

s, and uses an eight position, eight conductor (8P8C) modular connector

Modular connector

.

RJ61 specifies the wiring pinout

Pinout

In electronics, a pinout is a cross-reference between the contacts, or pins, of an electrical connector or electronic component, and their functions.- Purpose :...

of the connector as follows:

RJ61 wiring (USOC)
Pin	Pair	Wire	\| Color
1	4	tip	White/Brown
2	3	tip	White/Green
3	2	tip	White/Orange
4	1	ring	Blue/White
5	1	tip	White/Blue
6	2	ring	Orange/White
7	3	ring	Green/White
8	4	ring	Brown/White

This pinout is for multi-line telephone use only; RJ61 is unsuitable for use with high-speed data, because the pins for pairs 3 and 4 are too widely spaced for high signaling frequencies. T1 line

Digital Signal 1

s use another wiring for the same connector, designated RJ48. Ethernet over twisted pair

Ethernet over twisted pair

(10BASE-T

10BASE-T

, 100BASE-TX and 1000BASE-T) also use a different wiring for the same connector, either T568A or T568B. RJ48, T568A, and T568B are all designed to keep pins close together for pairs 3 and 4.

The flat 8-conductor "silver satin" cable traditionally used with 4-line analog telephones and RJ61 jacks is also unsuitable for use with high-speed data. Twisted pair cabling must be used with RJ48, T568A and T568B. Note that data twisted pair patch cable used with the three data standards above is not a direct replacement for RJ61 cable, because RJ61 pairs 3 and 4 would be split among different patch cable twisted pairs, causing cross-talk between voice lines 3 and 4 that might be noticeable for long patch cables.

With the advent of structured wiring systems and TIA/EIA-568-B conventions, the RJ61 pinout is falling into disuse. The T568A and T568B standards are used in place of RJ61 so that a single wiring standard in a facility can be used for both voice and data.

External links

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

Naming confusion

Twisted pair

History and authority

International use

Common types

List of official registered jacks

Unofficial plug names

RJ11, RJ14, RJ25 wiring details

Pinouts

Powered version of RJ11

Compatibility with structured cabling

RJ21

RJ45

Crossover Cables

RJ48

RJ61

See also

Further reading

External links