Editing Telephone jack and plug

{{Short description|Connectors for wiring of telephone equipment}}
{{Distinguish|Phone connector (audio)}}
[[Image:Photo-RJ11-MF.jpg|thumb|Modular connector 6P6C plug (left) and 6P4C jack (right)]]
A '''telephone jack''' and a '''telephone plug''' are [[electrical connector]]s for connecting a [[telephone]] set or other [[telecommunications]] apparatus to the telephone wiring inside a building, establishing a connection to a telephone network. The plug is inserted into its counterpart, the [[Jack (connector)|jack]], which is commonly affixed to a wall or baseboard. The standards for telephone jacks and plugs vary from country to country, though the 6P2C style modular plug has become by far the most common type.

A connection standard, such as [[Registered_jack#RJ11|RJ11]], specifies not only the physical aspects of an [[electrical connector]], but also the signal definitions for each contact, and the [[pinout]] of the device, i.e. the assignment or function of each contact.<ref>{{cite book
| last1       = Semenov
| first1      = Andrey B.
| last2       = Strizhakov
| first2      = Stanislav K.
| last3       = Suncheley
| first3      = Igor R.
| title       = Structured cable systems
| edition     = 1st
| date        = October 3, 2002
| publisher   = [[Springer Science+Business Media|Springer]]
| isbn        = 3-540-43000-8
| page        = 129
| chapter     = Electrical Cable Connectors
| quote       = The abbreviation for registered jack, RJ defines a particular wiring scheme of individual wires into outlet contacts. For example, a 6-position outlet may be wired to RJ-11C scheme (one pair), RJ-14C (two pairs), or RJ-25C (three pairs).
}}</ref> Modular connectors are specified for the [[registered jack]] (RJ) series of connectors, as well as for [[Ethernet]] and other connectors, such as [[4P4C]] (4 position, 4 contacts) modular connectors, the de facto standard on handset cords,<ref>{{cite book
| author      = BICSI
| title       = Telecommunications Cabling Installation
| edition     = 2nd
| date        = October 7, 2002
| publisher   = [[McGraw-Hill Professional]]
| isbn        = 0-07-140979-3
| page        = 88
| chapter     = Background Information
| quote       = 4-position and 4-contact connectors are used primarily for telephone handset cords.
}}</ref> often improperly<ref>{{cite book
| last        = Trulove
| first       = James
| title       = LAN wiring
| edition     = 3rd
| date        = December 19, 2005
| publisher   = [[McGraw-Hill Professional]]
| isbn        = 0-07-145975-8
| page        = 219
| chapter     = User Cords and Connectors
| quote       = This 8-pin modular plug is probably the most subject to name abuse, because it resembles the specialized RJ-45 connector. However, the RJ-45 wiring pattern (which includes an interface programming resistor) is so radically different from that of T568A and B that it really should not be called by that name at all.
}}</ref><ref>{{cite book
| last1       = Oliviero
| first1      = Andrew
| last2       = Woodward
| first2      = Bill
| title       = Cabling: The Complete Guide to Copper and Fiber-Optic Networking
| edition     = 4th
| date        = July 20, 2009
| publisher   = [[Sybex]]
| isbn        = 978-0-470-47707-6
| page        = 294
| chapter     = Connectors
| quote       = The RJ (registered jack) prefix is one of the most widely (and incorrectly) used prefixes in the computer industry; nearly everyone, including people working for cabling companies, is guilty of referring to an eight-position modular jack (sometimes called an 8P8C) as an RJ-45.
}}</ref> referred to as ''RJ connectors''.

==History==
Historically, telephones were typically owned by the telephone company, and were usually permanently wired to the [[telephone line]]. For some applications it was necessary or convenient to provide portable telephone sets that could be moved to a different location within the customer's premises. For this purpose telephone companies developed jacks and plugs in various designs with various numbers of contacts. Before {{Circa|1930}}, concentric connectors with three contacts were usually sufficient, but the upgrade of telephone sets to anti-[[sidetone]] circuitry in the 1930s required at least four conductors between a desk set and the [[subscriber set]] that contained the [[telephone hybrid]] and a [[Ringing (telephony)|ringer]]. For this purpose, Bell System engineers developed a cube-shaped four-prong plug (type no. 283) with uneven prong spacings to avoid improper insertion into the jack.<ref name=blr1949>{{cite journal |title=Jacks and Plugs for Portable Telephones |journal=[[Bell Laboratories Record]] |last=Krantz |first=H.K. |date=July 1944 |volume=12 |issue=7 |pages=343–346 |url=https://worldradiohistory.com/Archive-Bell-Laboratories-Record/30s/Bell-Laboratories-Record-1934-07.pdf#page=22 |access-date=October 28, 2022}}</ref><ref>AT&T, ''Jacks and Plugs'', Bell System Practices, [http://etler.com/docs/BSP/C/C36/C36.201_I1.pdf Section C36.201 Issue 1] (February 1, 1932)</ref>

The cubic design was changed to a round version (No. 505A) in the mid 1960s. The four-prong jack and plug combination was the standard line connection for all portable telephone sets until the conversion to [[modular jack]]s in the 1970s, typified by the [[Registered Jack]] standards promulgated in U.S. federal law.

Many countries initially used different specifications for connectors, and some national connector types remain in service, but few are used for new installations for which modular connector types are prescribed.

<gallery>
file:Western Electric 404A and 283B four-prong telephone jack and plug combination ca1960.jpg|Bell System Type 404A jack and type 283B plug ({{Circa|1960}})
Image:4 prong plug jeh.jpg|Trimline telephone line cord with a Type 505A wall plug and modular set plug (mid-1960s)
File:Four-prong telephone jack, 1960s, front.jpg|The front of a US four-pronged telephone jack (1964)
File:Four-prong telephone jack, 1960s, back.jpg|The back of a US four-pronged telephone jack (1964)
</gallery>

==Connections==
The installation of a conventional wired [[telephone]] set has four connection points, each of which may be hardwired, but more often use a plug and socket:
*telephone line to phone cord: The wall jack. This connection is the most standardized, and often regulated as the boundary between an individual's telephone and the telephone network. In many residences, though, the boundary between utility-owned and household-owned cabling is a network interface on an outside wall known as the demarcation point; all wall jacks in the home are part of the household's internal wiring.
*telephone cord to telephone set base: This connection is generally not regulated, but instead follows de facto standards. It is often a [[6P4C]] connector, which is often [[RJ11]], but may be proprietary or hardwired.
*telephone set base to handset cord: By de facto standard, this is usually a [[4P4C]] connector. 
*handset cord to handset: The handset end of the [[straight-through cable|straight-through handset cord]] also uses a [[4P4C]] connector.

Some of these may be absent: Wired telephones may not have a separate base and handset. The defining characteristic of wireless telephones is that they do not have a handset cord, and the defining characteristic of mobile telephones is that they do not have a phone cord.

==Wiring==
[[File:Phone Cable.jpg|thumb|Typical U.S. modular phone connector]]
A standard specifies both a physical connector and how it is wired. Sometimes the same connector is used by different countries but wired in different ways.

For example, telephone cables in the [[United Kingdom|UK]] typically have a [[BS 6312]] (UK standard) plug at the wall end and a 6P4C or 6P2C [[modular connector]] at the telephone end: this latter may be wired as per the RJ11 standard (with pins 3 and 4), or it may be wired with pins 2 and 5, as a straight-through cable from the BT plug (which uses pins 2 and 5 for the line, unlike RJ11, which uses pins 3 and 4). Thus cables are not in general compatible between different phones, as the phone base may have a socket with pins 2 and 5 (requiring a straight-through cable), or have an RJ11 socket (requiring a [[crossover cable]]).

When [[modular connector]]s are used, the latch release of the connector should be on the ridge side of flat phone wire in order to maintain polarity.

Though four wires are typically used in U.S. phone cabling, only two are necessary for telecommunication. In the event that a second line is needed, the other two are used.  They are also sometimes used to provide power for telephone dial lamps (6 volts AC, as in the [[Princess phone]]), or other features.

==List of plugs==
:{{Expand list|date=January 2009}}

===Modular connectors===
{{Main|Modular connector}}

*[[4P4C]] and [[4P2C]] for handset cables (often erroneously referred to as RJ9, RJ10, and RJ22)
*[[6P2C]] for [[RJ11]] single telephone line
*[[6P4C]] for [[RJ14]] two telephone lines
*[[6P6C]] for [[RJ25]] three telephone lines
*[[8P8C]] for [[RJ61]]X four telephone lines, [[RJ48]]S and RJ48C for four-wire data lines, [[RJ31]]X single telephone line with equipment disconnect, [[RJ38]]X (similar to RJ31X but with continuity circuit)

===Other connectors===
*50-pin [[micro ribbon|miniature ribbon]] connector for [[RJ21]]X, used for up to 25 lines for multiline phones such as the [[ITT 2564]], [[key telephone system]]s such as the [[1A2 Key System]], and [[Private branch exchange|PBX]] systems.

===International standards===
* [[RJ11]], by far the most common
* [[BS 6312]], British
* [[F-010]], French
* [[TAE connector]], German

===National standards===
* [[TDO-connector]], Austria
* [[WT-4]], Polish and Eastern Bloc national standard, also adopted in Russia as ШТР-IV (SHTR-IV)
<gallery>
File:WT-4 & RJ11 telephone plug.png|WT-4 telephone plug (A) with RJ11 outlet (B)
File:WT-4 & RJ11 telephone socket.png|GTN-4 telephone socket (A) with additional RJ11 socket (B)
</gallery>

The Polish WT-4 plug is also adopted in the [[Eastern Bloc]] and Russia as ШТР-IV (SHTR-IV) and has four metal pins and an additional fourth dielectric pin. The corresponding socket comes in two variants. The GTN-4 socket (РТШ-IV (RTSH-IV) in Russia) provides a 4 pin connection (in most cases, the two rightmost pins are used for connecting a single line). The GTNC-4 (РТШК-IV, RTSHK-IV) is a GTN-4 socket that has an additional circuit. The 5th plastic pin of the inserted plug disconnects a 1[[Microfarad|μF]] [[capacitor]] that otherwise closes the circuit of the telephone line when the plug is not inserted. This feature allows testing the line when the phone is not plugged in.<ref>{{Cite web|url=http://minsvyaz.ru/uploaded/files/Pravila_tekhnicheskogo_obsluzhivaniya_lineynykh_sooruzheniy_svyazi.pdf#page=4|title=Правила техобслуживания и ремонта линейных сооружений и оконечных устройств абонентских пунктов местных сетей связи|last=|first=|date=1996-07-10|website=|publisher=[[Ministry of Telecom and Mass Communications of the Russian Federation]]|language=Russian|access-date=}}</ref> The usage of a capacitor is mostly obsolete and GTN-4 sockets produced later reuse the capacitor compartment for an additional RJ11 socket.

===Legacy===
[[File:BTicino spina e presa telefonica.jpg|BTicino telephone plug and socket|thumb|right]]
* [[600 series connector]], Australia
* [[Protea (telephone)|Protea]], South Africa
* [[Swedish telephone plugs & sockets|SS 455 15 50]], Sweden and Iceland
* [[Telebrás]] plug, Brazil
* [[Tripolar plug]], Italy
* BTicino 2021 (with or without line interruption), Italy (rare)
{{clear}}

== List by country or territory ==
:{{Expand list|date=August 2008}}

This list covers only single-line telephone plugs commonly used in homes and other small installations; there are 44 different variations of plugs, including an Israeli version of BS6312 with different internal wiring of the pins, plus hard wiring to a junction box with no adapter. Special telephone sets use a variety of special plugs, for example [[micro ribbon]] for [[key telephone system]]s.

{| class="wikitable sortable"
|+
!Place
!Plug types
|-
||[[Albania]]|| [[6P2C]]
|-
||[[Algeria]]|| [[F-010]]
|-
||[[Argentina]]|| [[6P2C]]
|-
||[[Australia]]|| [[600 series connector|610]], [[6P2C]]
|-
||[[Austria]]|| [[TDO-connector|TDO]]
|-
||[[Barbados]]|| [[6P2C]]
|-
||[[Belarus]]|| [[6P2C]], Polish national 5-pin ([[WT-4]])&nbsp;{{r|group=Note|older}}
|-
||[[Belgium]]|| [[Tetrapolar plug]], [[6P2C]]
|-
||[[Bolivia]]|| [[6P2C]]
|-
||[[Bosnia and Herzegovina|Bosnia]]|| [[6P2C]], 3-pin plug used in countries of former [[Yugoslavia]]&nbsp;{{r|group=Note|older}}
|-
||[[Botswana]]|| [[BS 6312]]
|-
||[[Brazil]]|| Telebrás plug, [[6P2C]]
|-
||[[Brunei]]|| [[6P2C]]
|-
||[[Bulgaria]]|| [[6P2C]], Polish national 5-pin ([[WT-4]])&nbsp;{{r|group=Note|older}}
|-
||[[Canada]]|| [[6P2C]]
|-
||[[Cayman Islands]]|| [[6P2C]]
|-
||[[Chile]]|| [[6P2C]]
|-
||[[Mainland China|China Mainland]]|| [[6P2C]]
|-
||[[Colombia]]|| [[6P2C]], 2-pin national standard<ref>{{cite web
| url         = http://kropla.com/venezuela.htm
| title       = Columbia/Venezuela phone plug
| archiveurl  = https://web.archive.org/web/20080413045214/http://kropla.com/venezuela.htm
| archivedate = April 13, 2008
}}</ref>
|-
||[[Costa Rica]]|| [[6P2C]]
|-
||[[Croatia]]|| [[6P2C]], 3-pin plug used in countries of former [[Yugoslavia]]&nbsp;{{r|group=Note|older}}
|-
||[[Cyprus]]|| [[BS 6312]], [[6P2C]]<ref group=Note>Used for [[ADSL]]</ref>
|-
||[[Czech Republic]]|| [[6P2C]], 4-pin national plug&nbsp;{{r|group=Note|older}}
|-
||[[Denmark]]|| [[Danish telephone plug|3-prong national standard]], [[6P2C]]&nbsp;{{r|group=Note|newer}}
|-
||[[Dominican Republic]]|| [[6P2C]]
|-
||[[Ecuador]]|| [[6P2C]]
|-
||[[Egypt]]|| [[6P2C]]<ref group=Note>Currently the dominant plug</ref>
|-
||[[Estonia]]|| [[6P2C]], Polish national 5-pin ([[WT-4]])&nbsp;{{r|group=Note|older}}
|-
||[[Faroe Islands]]|| [[6P2C]]
|-
||[[Finland]]|| [[6P2C]], [[Tripolar plug]]&nbsp;{{r|group=Note|older}}
|-
||[[France]]|| [[F-010]], [[8P8C]]&nbsp;{{r|group=Note|RJ45}}{{r|group=Note|newer}} (since 2003)
|-
||[[Germany]]|| [[TAE connector|TAE]], [[8P8C]]&nbsp;{{r|group=Note|RJ45}}{{r|group=Note|ISDN}}
|-
||[[Gibraltar]]|| [[BS 6312]]
|-
||[[Greece]]|| [[6P2C]],<ref group=Note>Although other types can also be found</ref> Bipolar plug&nbsp;{{r|group=Note|older}}
|-
||[[Hong Kong]]|| [[6P2C]],&nbsp;{{r|group=Note|newer}} [[BS 6312]]
|-
||[[Hungary]]|| [[6P2C]], legacy 3 and 5-prong national standard<ref>{{cite web
| url         = http://www.szetszedtem.hu/399telefonkonnektor/regifele.htm
| title       = Régiféle telefonkonnektor
| trans-title = Old-school telephone connectors
| lang        = hu
}}</ref><ref>{{cite web
| url         = https://telefonmuzeum.hu/picture.php?/578/category/kiegeszitok
| title       = CB35 fali aljzat
| trans-title = CB35 wall connector
| lang        = hu
}}</ref>

|-
||[[Iceland]]|| [[6P2C]], [[SS 455 15 50]]&nbsp;{{r|group=Note|older}}
|-
||[[India]]|| [[6P2C]]
|-
||[[Indonesia]]|| [[6P2C]]
|-
||[[Iran]]|| [[6P2C]]
|-
||[[Republic of Ireland|Ireland]]|| [[6P2C]], [[8P8C]],&nbsp;{{r|group=Note|RJ45}}<ref group=Note>Used for ISDN, Digital PBX, and office systems</ref> 
|-
||[[Israel]]|| [[BS 6312]] but wired differently from the British Standard, [[6P2C]]
|-
||[[Italy]]|| [[6P2C]], [[Tripolar plug]],&nbsp;{{r|group=Note|older}} BTicino-2021
|-
||[[Japan]]|| [[6P2C]]
|-
||[[South Korea|Korea, Republic of]]|| 6-pin modular ([[6P4C]] or [[6P2C]]), 8-pin modular ([[8P8C]]) or 3-position weatherproof connector in accord with TIA-1096-A.<ref group=Note>Legal regulation</ref> 4-prong connector <ref group=Note>The old standard ruled out after 2002 but still used widely.</ref>
|-
||[[Latvia]]|| [[6P2C]], Polish national 5-pin ([[WT-4]])&nbsp;{{r|group=Note|older}}
|-
||[[Lithuania]]|| [[6P2C]], Polish national 5-pin ([[WT-4]])&nbsp;{{r|group=Note|older}}
|-
||[[Liechtenstein]]|| [[Reichle & De-Massari|Reichle-connector]], 4-pin Swiss telephone plugs&nbsp;{{r|group=Note|older}}
|-
||[[Luxembourg]]|| [[6P2C]], 4-pin Luxembourgish telephone plug&nbsp;{{r|group=Note|older}}
|-
||[[Malaysia]]|| [[6P2C]]
|-
||[[Malta]]|| [[BS 6312]], [[6P2C]]&nbsp;{{r|group=Note|newer}}
|-
||[[Mauritius]]|| [[F-010]]
|-
||[[Mexico]]|| [[6P2C]]
|-
||[[Montenegro]]|| [[6P2C]], 3-pin plug used in countries of former [[Yugoslavia]]&nbsp;{{r|group=Note|older}}
|-
||[[Morocco]]|| [[F-010]], [[6P2C]]
|-
||[[Myanmar]]|| [[BS 6312]]
|-
||[[Netherlands]]|| [[6P2C]], {{ill|PTT plug|wd=Q134582876|s=1|v=sup}}
|-
||[[Nigeria]]||[[6P2C]]
|-
||[[New Zealand]]|| [[BS 6312]], [[6P2C]],{{r|group=Note|newer}} [[8P8C]]&nbsp;{{r|group=Note|RJ45}}{{r|group=Note|newer}}
|-
||[[North Macedonia]]|| [[6P2C]], 3-pin plug used in countries of former [[Yugoslavia]]&nbsp;{{r|group=Note|older}}
|-
||[[Norway]]|| [[8P8C]],&nbsp;{{r|group=Note|RJ45}}{{r|group=Note|newer}}<ref group=Note>Same plug used for POTS, ISDN and LAN</ref> [[Tripolar plug]],&nbsp;{{r|group=Note|older}} [[:Image:Telephone plugs Norway.jpg|6-prong national standard]]<ref group=Note>For local battery telephones, not used since approximately 1980</ref>
|-
||[[Pakistan]]|| [[6P2C]]
|-
||[[Panama]]|| [[6P2C]]
|-
||[[Peru]]|| [[6P2C]]
|-
||[[Philippines]]|| [[6P2C]]
|-
||[[Poland]]|| [[6P2C]], Polish national 5-pin ([[WT-4]]) coupled with 6P2C socket&nbsp;{{r|group=Note|older}}
|-
||[[Portugal]]|| [[6P2C]]<ref group=Note>Also known as R.I.T.A.</ref>
|-
||[[Romania]]|| [[6P2C]], 3-pin triangular plug similar to the Italian [[Tripolar plug]],<ref group=Note>Rarely used today</ref> 5-pin R.S.-79.809<ref group=Note>Same as the Polish [[WT-4]]</ref>{{r|group=Note|older}}
|-
||[[Russia]]|| [[6P2C]], Polish national 5-pin ([[WT-4]])&nbsp;{{r|group=Note|older}}
|-
||[[Senegal]]|| [[F-010]]
|-
||[[Serbia]]|| [[6P2C]], 3-pin plug used in countries of former [[Yugoslavia]]&nbsp;{{r|group=Note|older}}
|-
||[[Singapore]]|| [[6P2C]]
|-
||[[Slovenia]]|| [[6P2C]], 3-pin plug used in countries of former [[Yugoslavia]]&nbsp;{{r|group=Note|older}}
|-
||[[Slovakia]]|| [[6P2C]], 4-pin national plug&nbsp;{{r|group=Note|older}}
|-
||[[South Africa]]|| [[6P2C]], [[Protea (telephone)|Protea]], [[8P8C]]&nbsp;{{r|group=Note|RJ45}}{{r|group=Note|ISDN}}
|-
||[[Spain]]|| [[6P2C]]
|-
||[[Sri Lanka]]|| [[6P2C]]
|-
||[[Sweden]]|| [[SS 455 15 50]], [[6P2C]]
|-
||[[Switzerland]]|| [[Reichle & De-Massari|Reichle-connector]], 4-pin plugs&nbsp;{{r|group=Note|older}}
|-
||[[Taiwan]]|| [[6P2C]]
|-
||[[Thailand]]|| [[6P2C]]
|-
||[[Trinidad and Tobago]]|| [[6P2C]]
|-
||[[Turkey]]|| [[6P2C]], [[Tripolar plug]]&nbsp;{{r|group=Note|older}}
|-
||[[Tunisia]]|| [[6P2C]], [[F-010]]&nbsp;{{r|group=Note|older}}
|-
||[[Ukraine]]|| [[6P2C]], Polish national 5-pin ([[WT-4]])&nbsp;{{r|group=Note|older}}
|-
||[[United Arab Emirates]]|| [[BS 6312]]
|-
||[[United Kingdom]]|| [[BS 6312]], [[6P2C]]<ref group=Note>Used for [[ADSL]] modem lines in [[British telephone sockets]]</ref>
|-
||[[United States]]|| [[6P2C]] and other [[Registered jack]]s, 4-pin [[Bell System]] plugs&nbsp;{{r|group=Note|older}}
|-
||[[Uruguay]]|| [[6P2C]]
|-
||[[USSR]] (history)|| Polish national 5-pin ([[WT-4]])
|-
||[[Venezuela]]|| [[6P2C]]
|-
||[[Zimbabwe]]|| [[BS 6312]], [[6P2C]]
|}

{{reflist|group=Note|refs=
<ref name="older">Used in older installations</ref>
<ref name="newer">Used in newer installations</ref>
<ref name="RJ45">Often, although incorrectly referred to as "RJ45"</ref>
<ref name="ISDN">Used for [[ISDN]]</ref>
}}

==See also==
* [[Network interface device]]
* [[List of countries with mains power plugs, voltages and frequencies|Power plugs/sockets by country]]

==References==
{{reflist}}

==External links==
{{Commons|Telefonadapter|Telephone adaptor}}
* [https://web.archive.org/web/20040911010046/http://kropla.com/phones2.htm Telephone plug list]—at Steve Kropla's World Wide Phone Guide
* [http://www.tech-faq.com/telephone-wiring.shtml How to install telephone wiring]

[[Category:Telephone connectors| ]]