An RJ11 socket is the standard phone connection jack used in the United States. It contains wiring that connects individual telephone lines to a larger telecommunications network. Most RJ11 socket wiring uses what are referred to as three and four pin connectors to transmit electrical currents through telephone wiring.
There are several different types of RJ11 socket connections. While the most standard is the phone jack on the interior wall of a building that phone subscribers plug a handset into, sockets also exist to connect telephone cable from a computer to a modem device. In addition, older telephone sets may have RJ11 sockets that connect wiring from a receiver to a dialing base. Telephone wiring adapters and splitters also contain RJ11 sockets.
Wiring adapters can be used in countries that operate under a different type of phone wiring system. An adapter will usually contain one end that has wiring compatible with a local area's phone jacks. The other end will contain an RJ11 socket that a telephone device can plug into. Adapters convert and send the voice signals as if there were only one type of wiring in use.
The majority of telephone wiring systems operates under the RJ11 standard. RJ11 connections continue to be used for landline phones. In the past they were also used to provide dial-up Internet service. Computer manufacturers typically provided an RJ11 socket on the back of hard drives to directly connect to a wall jack. Internal hard-drive modems helped convert the transmissions into data that computer devices sent over the phone company's network.
Many buildings and homes in the United States are still equipped with RJ11 sockets, although the use of traditional landline service has steadily declined with the introduction of mobile phones and broadband phone service. Businesses find that traditional landline service is still necessary to provide connection reliability and other data communications, such as faxes. Wall plate sockets will not work unless they are activated by the local telephone company, but the wiring is in place for potential activation.
Each wall plate socket connects directly to a telephone company's network. Wiring extends from the jack and through the building's interior to an outside point of entry. Another corresponding set of wires extends from the point of entry to outside telephone cables that may be underground or suspended on telephone poles.
An RJ11 socket is usually wired to accept four different areas of contact or connection between wires. When one end of the wire plugs into the jack, each pin connection matches up with another accordingly. These connections facilitate the transfer of electrical current and voice or data transmissions.