Teléfono: Diferenzas entre revisións
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Liña 45:
Unha comunicación de voz ocupa un ancho de banda de 3.100 [[Hz]], pero os operadores acostuman a reservar 4.000 Hz para cada canle de voz.
== Símbolos ==
Os símbolos gráficos empregados para designar servizos telefónicos ou información relacionada co teléfono en carteis e outros medios inclúen ℡ ([[Unicode|U+]]2121), <big>☎</big> ([[Unicode|U+]]260E), <big>☏</big> ([[Unicode|U+]]260F), <big>✆</big> ([[Unicode|U+]]2706) e <big>⌕</big> ([[Unicode|U+]]2315).
== Uso ==
A finais de 2009 había un total de seis mil millóns de subscritores con liñas telefónicas no mundo, incluíndo 1260 millóns de liñas fixas e 4600 millóns de móbiles.<ref>[http://www.itu.int/newsroom/press_releases/2007/20.html Next-Generation Networks Set to Transform Communications], International Telecommunications Union website, 4-9-2007. Consultado o 5-7-2009.</ref>
== Notas ==
Liña 50 ⟶ 56:
==Véxase tamén==
{{Commonscat}}
=== Bibliografía ===
* Brooks, John (1976). ''Telephone: The first hundred years''. HarperCollins.
* {{cita libro|apelidos=Bruce|nome=Robert V. |título=Bell: Alexander Graham Bell and the Conquest of Solitude|url=https://books.google.com/books?id=ZmR0MOQAu0UC|data=1990|editorial=Cornell University Press}}
* Casson, Herbert Newton. (1910) ''The history of the telephone'' [https://books.google.com/books?hl=en&lr=&id=cw4LAAAAIAAJ&oi=fnd&pg=PA11&dq=history+telephone&ots=dyAdF1QVO1&sig=GmRsKGwqcmtRiDpToxwmrkBLG8M online].
* Coe, Lewis (1995). ''The Telephone and Its Several Inventors: A History.'' Jefferson, NC: McFarland & Co.
* Evenson, A. Edward (2000). ''The Telephone Patent Conspiracy of 1876: The Elisha Gray – Alexander Bell Controversy.'' Jefferson, NC: McFarland & Co.
* Fischer, Claude S. (1994) ''America calling: A social history of the telephone to 1940'' (Univ of California Press, 1994)
* Huurdeman, Anton A. (2003). ''The Worldwide History of Telecommunications'' Hoboken: NJ: Wiley-IEEE Press.
* John, Richard R. (2010). ''Network Nation: Inventing American Telecommunications.'' Cambridge, MA: Harvard University Press.
* MacDougall, Robert. ''The People's Network: The Political Economy of the Telephone in the Gilded Age.'' Philadelphia: University of Pennsylvania Press.
* Mueller, Milton. (1993) "Universal service in telephone history: A reconstruction." ''Telecommunications Policy'' 17.5 (1993): 352-369.
* Todd, Kenneth P. (1998), [http://www.porticus.org/bell/capsule_bell_system.html ''A Capsule History of the Bell System'']. American Telephone & Telegraph Company (AT&T).
=== Ligazóns externas ===
* [http://galbithink.org/telcos/early-telephone-data.htm Early U.S. Telephone Industry Data]
* [https://web.archive.org/web/20120119174634/http://www.1911encyclopedia.org/Telephone 1911 Britannica "Telephone" article]
* [http://www.sparkmuseum.com/TELEPHONE.HTM Virtual museum of early telephones]
* [http://www.theengineer.co.uk/Articles/294346/July+1877+The+Telephone.htm The Telephone, 1877]
* [http://en.citizendium.org/wiki/Telephone Telephone] Citizendium
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