{{Unreferenced, date=May 2019, bot=noref (GreenC bot) Telefonadapter 07

The telefonic tripolar plug is the first type of

telephone plug A telephone jack and a telephone plug are electrical connectors 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 inserte ...

used in

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

. It has also been used in

Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of B ...

Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...

and

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...

in older installations.

Structure

It uses three pins: the two on the top are joined with the

twisted pair Twisted pair cabling is a type of wiring used for communications in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility. Compared to a single conductor or an untwisted ba ...

of cables bringing the signal; the third, off-center, can be used for loop through when more sockets exist. In Finland, the third pin is earth ground, but it is rarely connected. Every socket complies with Italian standards. Formerly each of them was installed by SIP, now TIM, and had their trademark. Sockets without trademark exist also. Since 2007, TIM no longer installs tripolar sockets in new electrical wiring systems. In Finland, five-pin variant with second line also exists. Three-pin plug is compatible with five-pin socket.

Use

The tripolar plug has been supplanted by the international

RJ11 A registered jack (RJ) is a standardized telecommunication network interface for connecting voice and data equipment to a service provided by a local exchange carrier or long distance carrier. Registration interfaces were first defined in th ...

standard, both because it is more diffused in new technology devices and because the tripolar plug isn't suitable for

ISDN Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Wo ...

. Telephone connectors