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Encyclopedia > Telephone line

A telephone line (or just line) is a single-user circuit on a telephone communications system. Typically this refers to the physical wire or other signalling medium connecting the user's telephone aparatus to the telecommunications network, and usually also implies a single telephone number for billing purposes reserved for that user. This article needs to be cleaned up to conform to a higher standard of quality. ... The term communications is used in a number of disciplines: Communications, also known as communication studies is the academic discipline which studies communication. ... Telecommunication is the extension of communication over a distance. ...

In 1876 the earliest lines were single electrically conducting metal wires directly connecting one telephone to another with the Earth forming the return circuit. Later in 1878 the Bell Telephone Company ran lines (the local loop) from each user's telephone to end offices which performed any necessary electrical switching to allow voice signals to be transmitted to more distant telephones. 1876 is a leap year starting on Saturday. ... 1878 was a common year starting on Tuesday (see link for calendar). ... The Bell System is an informal name given to the US telecommunications company American Telephone & Telegraph Company (AT&T) before AT&T divested its local exchange telephone service operating companies on January 1, 1984. ... In telecommunications, the local loop is the wiring between the central office (telephone exchange in British English) and the customers premises demarcation point. ... In the field of telecommunications, a telephone exchange (US: telephone switch) is a piece of equipment that connects phone calls. ...

These wires were typically copper, although aluminium has also been used, and were carried in pairs separated by about 25 cm on poles above the ground, and later as twisted pair cables. Modern lines may run underground to a device that converts the analogue signal to digital for transmission on optical fiber. General Name, Symbol, Number copper, Cu, 29 Chemical series transition metals Group, Period, Block 11, 4, d Appearance copper, metallic Atomic mass 63. ... General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Atomic mass 26. ... 25 Pair Color Code Chart 10BASE-T UTP Cable Twisted pair cabling is a common form of wiring in which two conductors are wound around each other for the purposes of cancelling out electromagnetic interference known as crosstalk. ... For the Analog Science Fiction and Science Fact publication, see Astounding Magazine. ...

Most houses in the U.S. are wired with (4 conductor) RJ-11 copper wire that is capable of handling 2 telephone lines. Those conductors run to the local POP. When a local call is made, a switch connects that local loop to the local loop of the number that was dialed. RJ-11 is a physical interface often used for terminating twisted pair type cables. ... Electrical switches. ... In telecommunications, the local loop is the wiring between the central office (telephone exchange in British English) and the customers premises demarcation point. ...

  Results from FactBites:
ATCS Newsletter The Evolution of Telephone Cable (0 words)
Telephone lines were needed to connect private telephones with the central interconnection facility.
Telephone cables were needed to replace the large number of aerial wires present in the cities.
Improvements were continually being made to telephone cable, the use of more and finer conductors in a given cable, lower electrostatic capacity requirements and a larger air to paper ratio of the insulation.
Requirements for New Telephone Lines (0 words)
A decision on whether or not to provide additional telephone lines after January, augment the existing telephone system, or begin obtaining temporary telephone service from GTE should be made with ample time for implementation.
Move some telephone equipment (e.g., modems and emergency telephones) off of the GTD4600 onto GTE business lines in an effort to extend the useful life of the current configuration until July, 1996 and then replace the system in July, 1997.
Requests for new telephone lines between July, 1996 and July, 1997 could not be satisfied and the campus community would probably not accept this option.
  More results at FactBites »



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