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. The standard for telephone plugs varies from country to country, though the RJ11 "modular connector" has become by far the most common.

A connection standard, such as "RJ11", specifies not only the physical connector, but how it is wired (the "pinout").[1] Modular connectors are specified for the Registered Jack 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 cables,[2] often improperly[3][4] referred to as "RJ" connectors.

Contents

History

Historically the telephone was often owned by the supplier and permanently wired in to the telephone line they supplied but as phone markets became more deregulated there was a need for a simple plug-in interface that consumers could use. Many countries initially used their own connectors. For example Bell System companies in the 1960s used a round plug about 40mm in diameter with four prongs about 15mm apart. National connectors remain in service but few are used for new installations.

List of connections

On a conventional wired telephone, there are 4 connections, each of which may be hardwired, but more often uses a plug and socket:

telephone line to phone cable
The wall jack. This connection is the most standardized, and often regulated as the boundary between an individual's telephone and the phone network. (In many homes, though, the boundary between utility-owned and household-owned cable is a jack on an outer wall; all wall jacks in the home are part of the household's internal wiring.)
phone cable to phone base
This and further connections is generally not regulated, but instead has de facto standards. It is often 6P4C, which is often RJ11, but may be proprietary or hardwired.
phone base to handset cable
handset cable to handset
The last two (the handset cable) has a de facto standard of a 4P4C connector with straight through cable.

Some of these may be absent:

Wiring

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 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 connectors 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 need be added, the other two are present.

Compatibility

Different telephone connections are generally compatible with the use of an adapter: the physical connector and its wiring is the primary incompatibility.

See: gallery of telephone adapters.

List of plugs

See also: List of registered jacks

Modular connectors

Main article: Modular connector

Other connectors

International standards

National standards

  1. WT-4
  2. RJ11
  3. Cable holes

Traditionally, the 5th plastic pin disconnects 1 μF capacitor that shorts telephone line while plug is not inserted into socket. In modern makes it does nothing electrical, and capacitor compartment was reused for additional RJ11 socket.

Legacy

List of countries and territories, with the plugs they use

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 of course 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 systems and the wide array of registered jacks.

Place Plug types
Albania RJ11
Algeria F-010
Argentina RJ11
Australia 610, RJ11
Austria TDO
Barbados RJ11
Belarus RJ11, Polish national 5-pin (WT-4) [Note 1]
Belgium Tetrapolar plug, RJ11
Bolivia RJ11
Bosnia RJ11, 3-pin plug used in countries of former Yugoslavia [Note 1]
Botswana BS 6312
Brazil Telebrás plug, RJ11
Brunei RJ11
Bulgaria RJ11, Polish national 5-pin (WT-4) [Note 1]
Canada RJ11
Cayman Islands RJ11
Chile RJ11
China Mainland RJ11
Colombia RJ11, 2-pin national standard[5]
Costa Rica RJ11
Croatia RJ11, 3-pin plug used in countries of former Yugoslavia [Note 1]
Cyprus BS 6312, RJ11[Note 2]
Czech Republic RJ11, 4-pin national plug [Note 1]
Denmark 3-prong national standard, RJ11 [Note 3]
Dominican Republic RJ11
Ecuador RJ11
Egypt RJ11[Note 4]
Estonia RJ11, Polish national 5-pin (WT-4) [Note 1]
Faroe Islands RJ11
Finland RJ11, 3-prong national standard [Note 1]
France F-010, 8P8C [Note 5][Note 3] (since 2003)
Germany TAE, 8P8C [Note 5][Note 6]
Gibraltar BS 6312
Greece RJ11[Note 7]
Hong Kong RJ11, [Note 3] BS 6312
Hungary RJ11
Iceland RJ11, SS 455 15 50 [Note 1]
India RJ11
Indonesia RJ11
Iran RJ11, CEI 23-16/VII, [Note 1] CEE 7/16 [Note 1]
Ireland RJ11, 8P8C, [Note 5][Note 8] 4 way post office jack [Note 9]
Israel BS 6312 but wired differently to the British Standard], RJ11
Italy Tripolar plug, RJ11, BTicino 2021
Japan RJ11
Latvia RJ11, Polish national 5-pin (WT-4) [Note 1]
Lithuania RJ11, Polish national 5-pin (WT-4) [Note 1]
Liechtenstein Reichle-connector, 4-pin Swiss telephone plugs [Note 1]
Luxembourg RJ11, 4-pin luxembourgish telephone plug [Note 1]
Macedonia RJ11, 3-pin plug used in countries of former Yugoslavia [Note 1]
Malaysia RJ11
Malta BS 6312, RJ11 [Note 3]
Mexico RJ11
Montenegro RJ11, 3-pin plug used in countries of former Yugoslavia [Note 1]
Morocco F-010, RJ11
Netherlands RJ11, Dutch telephone plug
Nigeria RJ11
New Zealand BS 6312, RJ11,[Note 3] 8P8C [Note 5][Note 3]
Norway 8P8C, [Note 5][Note 3][Note 10] 3-prong national standard, [Note 1] 6-prong national standard[Note 11]
Pakistan RJ11
Panama RJ11
Peru RJ11
Philippines RJ11
Poland RJ11, Polish national 5-pin (WT-4) coupled with RJ11 socket [Note 1]
Portugal RJ11[Note 12]
Romania RJ11, 3-pin triangular plug similar to the Italian Tripolar plug,[Note 13] 5-pin R.S.-79.809[Note 14][Note 1]
Russia RJ11, Polish national 5-pin (WT-4) [Note 1]
Serbia RJ11, 3-pin plug used in countries of former Yugoslavia [Note 1]
Singapore RJ11
Slovenia RJ11, 3-pin plug used in countries of former Yugoslavia [Note 1]
Slovakia RJ11, 4-pin national plug [Note 1]
South Africa RJ11, Protea, 8P8C [Note 5][Note 6]
South Korea 4-pin standard plug, RJ11[Note 15]
Spain RJ11
Sri Lanka RJ11
Sweden SS 455 15 50, RJ11
Switzerland Reichle-connector, 4-pin plugs [Note 1]
Taiwan RJ11
Thailand RJ11
Trinidad and Tobago RJ11
Turkey RJ11
Ukraine RJ11, Polish national 5-pin (WT-4) [Note 1]
United Arab Emirates BS 6312
United Kingdom BS 6312, RJ11[Note 16]
United States RJ11 and other Registered jacks, 4-pin Bell System plugs [Note 1]
Uruguay RJ11
Venezuela RJ11
Zimbabwe BS 6312, RJ11
  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z Used in older installations
  2. ^ Used for ADSL
  3. ^ a b c d e f g Used in newer installations
  4. ^ Currently the dominant plug
  5. ^ a b c d e f Often, although incorrectly referred to as "RJ45"
  6. ^ a b Used for ISDN
  7. ^ Although other types can also be found
  8. ^ Used for ISDN, Digital PBX, and office systems
  9. ^ Used for pre mid-1980's installations
  10. ^ Same plug used for POTS, ISDN and LAN
  11. ^ For local battery telephones, not used since approximately 1980
  12. ^ Also known as R.I.T.A.
  13. ^ Rarely used today
  14. ^ Same as the Polish WT-4
  15. ^ For special use
  16. ^ Used for ADSL British telephone sockets

See also

References

  1. ^ Semenov, Andrey B.; Strizhakov, Stanislav K.; Suncheley, Igor R. (October 3, 2002). "Electrical Cable Connectors". Structured cable systems (1st ed.). Springer. p. 129. ISBN 3-540-43000-8. "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)." 
  2. ^ BICSI (October 7, 2002). "Background Information". Telecommunications Cabling Installation (2nd ed.). McGraw-Hill Professional. p. 88. ISBN 0-07-140979-3. "4-position and 4-contact connectors are used primarily for telephone handset cords." 
  3. ^ Trulove, James (December 19, 2005). "User Cords and Connectors". LAN wiring (3rd ed.). McGraw-Hill Professional. p. 219. ISBN 0-07-145975-8. "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." 
  4. ^ Oliviero, Andrew; Woodward, Bill (July 20, 2009). "Connectors". Cabling: The Complete Guide to Copper and Fiber-Optic Networking (4th ed.). Sybex. p. 294. ISBN 0-470-47707-5. "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." 
  5. ^ "Columbia/Venezuela phone plug". Archived from the original on April 13, 2008. http://web.archive.org/web/20080413045214/http://kropla.com/venezuela.htm. 

External links