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data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-First_telephone_call" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#First_telephone_call"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>First telephone call</span> </div> </a> <ul id="toc-First_telephone_call-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Information_transmission" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Information_transmission"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Information transmission</span> </div> </a> <ul id="toc-Information_transmission-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Costs" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Costs"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Costs</span> </div> </a> <ul id="toc-Costs-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Placing_a_call" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Placing_a_call"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Placing a call</span> </div> </a> <button aria-controls="toc-Placing_a_call-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Placing a call subsection</span> </button> <ul id="toc-Placing_a_call-sublist" class="vector-toc-list"> <li id="toc-Details_of_operation" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Details_of_operation"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Details of operation</span> </div> </a> <ul id="toc-Details_of_operation-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Tones" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Tones"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Tones</span> </div> </a> <ul id="toc-Tones-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Unwanted_calls" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Unwanted_calls"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Unwanted calls</span> </div> </a> <ul id="toc-Unwanted_calls-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Patents" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Patents"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Patents</span> </div> </a> <ul id="toc-Patents-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Notes" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>Notes</span> </div> </a> <ul id="toc-Notes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" 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Available in 25 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-25" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">25 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%85%D9%83%D8%A7%D9%84%D9%85%D8%A9_%D9%87%D8%A7%D8%AA%D9%81%D9%8A%D8%A9" title="مكالمة هاتفية – Arabic" lang="ar" hreflang="ar" data-title="مكالمة هاتفية" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Trucada_telef%C3%B2nica" title="Trucada telefònica – Catalan" lang="ca" hreflang="ca" data-title="Trucada telefònica" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Telefonn%C3%AD_hovor" title="Telefonní hovor – Czech" lang="cs" hreflang="cs" data-title="Telefonní hovor" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Telefongespr%C3%A4ch" title="Telefongespräch – German" lang="de" hreflang="de" data-title="Telefongespräch" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Telefonik%C3%B5ne" title="Telefonikõne – Estonian" lang="et" hreflang="et" data-title="Telefonikõne" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%A4%CE%B7%CE%BB%CE%B5%CF%86%CF%89%CE%BD%CE%B9%CE%BA%CE%AE_%CE%BA%CE%BB%CE%AE%CF%83%CE%B7" title="Τηλεφωνική κλήση – Greek" lang="el" hreflang="el" data-title="Τηλεφωνική κλήση" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Llamada_telef%C3%B3nica" title="Llamada telefónica – Spanish" lang="es" hreflang="es" data-title="Llamada telefónica" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Telefono-dei" title="Telefono-dei – Basque" lang="eu" hreflang="eu" data-title="Telefono-dei" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%AA%D9%85%D8%A7%D8%B3_%D8%AA%D9%84%D9%81%D9%86%DB%8C" title="تماس تلفنی – Persian" lang="fa" hreflang="fa" data-title="تماس تلفنی" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Appel_t%C3%A9l%C3%A9phonique" title="Appel téléphonique – French" lang="fr" hreflang="fr" data-title="Appel téléphonique" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Chamada_telef%C3%B3nica" title="Chamada telefónica – Galician" lang="gl" hreflang="gl" data-title="Chamada telefónica" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Panggilan_telepon" title="Panggilan telepon – Indonesian" lang="id" hreflang="id" data-title="Panggilan telepon" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%A9%D7%99%D7%97%D7%AA_%D7%98%D7%9C%D7%A4%D7%95%D7%9F" title="שיחת טלפון – Hebrew" lang="he" hreflang="he" data-title="שיחת טלפון" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-gcr mw-list-item"><a href="https://gcr.wikipedia.org/wiki/Ap%C3%A8l_t%C3%A9l%C3%A9fonik" title="Apèl téléfonik – Guianan Creole" lang="gcr" hreflang="gcr" data-title="Apèl téléfonik" data-language-autonym="Kriyòl gwiyannen" data-language-local-name="Guianan Creole" class="interlanguage-link-target"><span>Kriyòl gwiyannen</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Chamada_telef%C3%B4nica" title="Chamada telefônica – Portuguese" lang="pt" hreflang="pt" data-title="Chamada telefônica" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Apel_telefonic" title="Apel telefonic – Romanian" lang="ro" hreflang="ro" data-title="Apel telefonic" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%A2%D0%B5%D0%BB%D0%B5%D1%84%D0%BE%D0%BD%D0%BD%D1%8B%D0%B9_%D1%80%D0%B0%D0%B7%D0%B3%D0%BE%D0%B2%D0%BE%D1%80" title="Телефонный разговор – Russian" lang="ru" hreflang="ru" data-title="Телефонный разговор" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikipedia.org/wiki/Thirrja" title="Thirrja – Albanian" lang="sq" hreflang="sq" data-title="Thirrja" data-language-autonym="Shqip" data-language-local-name="Albanian" class="interlanguage-link-target"><span>Shqip</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Telef%C3%B3nny_hovor" title="Telefónny hovor – Slovak" lang="sk" hreflang="sk" data-title="Telefónny hovor" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Puhelu" title="Puhelu – Finnish" lang="fi" hreflang="fi" data-title="Puhelu" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Telefon_g%C3%B6r%C3%BC%C5%9Fmesi" title="Telefon görüşmesi – Turkish" lang="tr" hreflang="tr" data-title="Telefon görüşmesi" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%A2%D0%B5%D0%BB%D0%B5%D1%84%D0%BE%D0%BD%D0%BD%D0%B8%D0%B9_%D0%B4%D0%B7%D0%B2%D1%96%D0%BD%D0%BE%D0%BA" title="Телефонний дзвінок – Ukrainian" lang="uk" hreflang="uk" data-title="Телефонний дзвінок" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-ur mw-list-item"><a href="https://ur.wikipedia.org/wiki/%D9%B9%DB%8C%D9%84%DB%8C%D9%81%D9%88%D9%86_%DA%A9%D8%A7%D9%84" title="ٹیلیفون کال – Urdu" lang="ur" hreflang="ur" data-title="ٹیلیفون کال" data-language-autonym="اردو" data-language-local-name="Urdu" class="interlanguage-link-target"><span>اردو</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a 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searchaux" style="display:none">Connection between two or more people over a telephone network</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">"Phone call" redirects here. For the 2013 British film, see <a href="/wiki/The_Phone_Call" title="The Phone Call">The Phone Call</a>.</div> <style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><table class="box-Update plainlinks metadata ambox ambox-content ambox-Update" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/5/53/Ambox_current_red_Americas.svg/42px-Ambox_current_red_Americas.svg.png" decoding="async" width="42" height="34" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/53/Ambox_current_red_Americas.svg/63px-Ambox_current_red_Americas.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/53/Ambox_current_red_Americas.svg/84px-Ambox_current_red_Americas.svg.png 2x" data-file-width="360" data-file-height="290" /></span></span></div></td><td class="mbox-text"><div class="mbox-text-span">This article needs to be <b>updated</b>.<span class="hide-when-compact"> Please help update this article to reflect recent events or newly available information.</span> <span class="date-container"><i>(<span class="date">May 2023</span>)</i></span></div></td></tr></tbody></table> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:CandlestickTelephoneGal.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/8/8d/CandlestickTelephoneGal.jpg/170px-CandlestickTelephoneGal.jpg" decoding="async" width="170" height="265" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/8d/CandlestickTelephoneGal.jpg/255px-CandlestickTelephoneGal.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/8d/CandlestickTelephoneGal.jpg/340px-CandlestickTelephoneGal.jpg 2x" data-file-width="556" data-file-height="866" /></a><figcaption>An early 20th century <a href="/wiki/Candlestick_telephone" title="Candlestick telephone">candlestick telephone</a> used for a phone call</figcaption></figure> <p>A <b>telephone call</b> or <b>telephone conversation</b> (or <b>telcon</b><sup id="cite_ref-TELCON_1-0" class="reference"><a href="#cite_note-TELCON-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>a<span class="cite-bracket">]</span></a></sup>), also known as a <b>phone call</b> or <b>voice call</b> (or simply a <b>call</b>), is a connection over a <a href="/wiki/Telephone_network" title="Telephone network">telephone network</a> between the <a href="/wiki/Called_party" title="Called party">called party</a> and the <a href="/wiki/Calling_party" title="Calling party">calling party</a>. Telephone calls started in the late 19th century. As technology has improved, a majority of telephone calls are made over a <a href="/wiki/Cellular_network" title="Cellular network">cellular network</a> through mobile phones or over the <a href="/wiki/Internet" title="Internet">internet</a> with <a href="/wiki/Voice_over_IP" title="Voice over IP">Voice over IP</a>.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> Telephone calls are typically used for real-time conversation between two or more parties, especially when the parties cannot meet in person. </p><p>A telephone call historically was between two live people. It has progressed to also include a live person and a recorded message, or a live person with an AI generated message. The term "call" is now broadly used for other connections over a network when you are using your voice to communicate (as opposed to typing text), including audio calls and <a href="/wiki/Video_call" class="mw-redirect" title="Video call">video calls</a>. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="First_telephone_call">First telephone call</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Telephone_call&action=edit&section=1" title="Edit section: First telephone call"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The first telephone call was made on March 10, 1876, by <a href="/wiki/Alexander_Graham_Bell" title="Alexander Graham Bell">Alexander Graham Bell</a>. Bell demonstrated his ability to "talk with electricity" by transmitting a call to his assistant, Thomas Watson. The first words transmitted were "Mr Watson, come here. I want to see you."<sup id="cite_ref-wired_4-0" class="reference"><a href="#cite_note-wired-4"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p><p>This event has been called Bell's "greatest success", as it demonstrated the first successful use of the telephone.<sup id="cite_ref-wired_4-1" class="reference"><a href="#cite_note-wired-4"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> Although it was his greatest success, he refused to have a telephone in his own home because it was something he invented by mistake and saw it as a distraction from his main studies.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (May 2016)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading2"><h2 id="Information_transmission">Information transmission</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Telephone_call&action=edit&section=2" title="Edit section: Information transmission"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A <a href="/wiki/Telephone" title="Telephone">telephone</a> call may carry ordinary <a href="/wiki/Human_voice" title="Human voice">voice</a> transmission using a telephone, <a href="/wiki/Data_transmission" class="mw-redirect" title="Data transmission">data transmission</a> when the calling party and called party are using <a href="/wiki/Modem" title="Modem">modems</a>, or <a href="/wiki/Fax" title="Fax">facsimile</a> transmission when they are using <a href="/wiki/Fax" title="Fax">fax</a> machines. The call may use <a href="/wiki/Land_line" class="mw-redirect" title="Land line">land line</a>, <a href="/wiki/Mobile_phone" title="Mobile phone">mobile phone</a>, <a href="/wiki/Satellite_phone" title="Satellite phone">satellite phone</a> or any combination thereof. When a telephone call has more than one <a href="/wiki/Called_party" title="Called party">called party</a> it is referred to as a <a href="/wiki/Conference_call" title="Conference call">conference call</a>. When two or more users of the network are sharing the same physical line, it is called a <a href="/wiki/Party_line_(telephony)" title="Party line (telephony)">party line</a> or Rural phone line. </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Photograph_of_First_Lady_Betty_Ford_Reading_a_Newspaper,_while_President_Ford_Talks_on_the_Telephone,_in_the_Second..._-_NARA_-_186793.tif" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a6/Photograph_of_First_Lady_Betty_Ford_Reading_a_Newspaper%2C_while_President_Ford_Talks_on_the_Telephone%2C_in_the_Second..._-_NARA_-_186793.tif/lossy-page1-220px-Photograph_of_First_Lady_Betty_Ford_Reading_a_Newspaper%2C_while_President_Ford_Talks_on_the_Telephone%2C_in_the_Second..._-_NARA_-_186793.tif.jpg" decoding="async" width="220" height="151" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a6/Photograph_of_First_Lady_Betty_Ford_Reading_a_Newspaper%2C_while_President_Ford_Talks_on_the_Telephone%2C_in_the_Second..._-_NARA_-_186793.tif/lossy-page1-330px-Photograph_of_First_Lady_Betty_Ford_Reading_a_Newspaper%2C_while_President_Ford_Talks_on_the_Telephone%2C_in_the_Second..._-_NARA_-_186793.tif.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a6/Photograph_of_First_Lady_Betty_Ford_Reading_a_Newspaper%2C_while_President_Ford_Talks_on_the_Telephone%2C_in_the_Second..._-_NARA_-_186793.tif/lossy-page1-440px-Photograph_of_First_Lady_Betty_Ford_Reading_a_Newspaper%2C_while_President_Ford_Talks_on_the_Telephone%2C_in_the_Second..._-_NARA_-_186793.tif.jpg 2x" data-file-width="3000" data-file-height="2060" /></a><figcaption>U.S. President <a href="/wiki/Gerald_Ford" title="Gerald Ford">Gerald Ford</a> on the phone</figcaption></figure> <p>If the caller's wired phone is connected directly to the calling party, when the caller takes their telephone <a href="/wiki/Off-hook" class="mw-redirect" title="Off-hook">off-hook</a>, the calling party's phone will ring. This is called a [hot line] or [ringdown]. Otherwise, the calling party is usually given a <a href="/wiki/Dial_tone" title="Dial tone">tone</a> to indicate they should begin dialing the desired number. In some (now very rare) cases, if the calling party cannot dial calls directly, they will be connected to an <a href="/wiki/Switchboard_operator" title="Switchboard operator">operator</a> who places the call for them. </p><p>Calls may be placed through a public network (such as the <a href="/wiki/Public_Switched_Telephone_Network" class="mw-redirect" title="Public Switched Telephone Network">Public Switched Telephone Network</a>) provided by a commercial <a href="/wiki/Telephone_company" class="mw-redirect" title="Telephone company">telephone company</a> or a private network called a [Private branch exchange|PBX]. In most cases a private network is connected to the public network in order to allow PBX users to dial the outside world. Incoming calls to a private network arrive at the PBX in two ways: either directly to a users phone using a <a href="/wiki/Direct_inward_dialing" class="mw-redirect" title="Direct inward dialing">DDI number</a> or indirectly via a receptionist who will answer the call first and then manually put the caller through to the desired user on the PBX. <sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (November 2015)">citation needed</span></a></i>]</sup> </p><p>Most telephone calls through the PSTN are set up using <a href="/wiki/ISDN_User_Part" title="ISDN User Part">ISUP</a> signalling messages or one of its variants between <a href="/wiki/Telephone_exchange" title="Telephone exchange">telephone exchanges</a> to establish the end to end connection. Calls through PBX networks are set up using <a href="/wiki/QSIG" title="QSIG">QSIG</a>, <a href="/wiki/DPNSS" class="mw-redirect" title="DPNSS">DPNSS</a> or variants. </p> <div class="mw-heading mw-heading2"><h2 id="Costs">Costs</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Telephone_call&action=edit&section=3" title="Edit section: Costs"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Some types of calls are not charged, such as <a href="/wiki/Local_call" title="Local call">local calls</a> (and internal calls) dialed directly by a telephone subscriber in <a href="/wiki/Canada" title="Canada">Canada</a>, the <a href="/wiki/United_States" title="United States">United States</a>, <a href="/wiki/Hong_Kong" title="Hong Kong">Hong Kong</a>, <a href="/wiki/United_Kingdom" title="United Kingdom">United Kingdom</a>, <a href="/wiki/Ireland" title="Ireland">Ireland</a> or <a href="/wiki/New_Zealand" title="New Zealand">New Zealand</a> (Residential subscribers only). In most other areas, all telephone calls are charged a fee for the connection. Fees depend on the provider of the service, the type of service being used (a call placed from a <a href="/wiki/Landline" title="Landline">landline</a> or wired telephone will have one rate, and a call placed from a <a href="/wiki/Mobile_telephone_number" class="mw-redirect" title="Mobile telephone number">mobile telephone</a> will have a different rate) and the distance between the calling and the called parties. In most circumstances, the calling party pays this fee. However, in some circumstances such as a reverse charge or <a href="/wiki/Collect_call" title="Collect call">collect call</a>, the called party pays the cost of the call. In some circumstances, the caller pays a <a href="/wiki/Flat_rate" title="Flat rate">flat rate</a> charge for the telephone connection and does not pay any additional charge for all calls made. Telecommunication liberalization has been established in several countries to allows customers to keep their local phone provider and use an alternate provider for a certain call in order to save money. </p> <div class="mw-heading mw-heading2"><h2 id="Placing_a_call">Placing a call</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Telephone_call&action=edit&section=4" title="Edit section: Placing a call"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Jean-Marc_Doussain.JPG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Jean-Marc_Doussain.JPG/170px-Jean-Marc_Doussain.JPG" decoding="async" width="170" height="255" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Jean-Marc_Doussain.JPG/255px-Jean-Marc_Doussain.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Jean-Marc_Doussain.JPG/340px-Jean-Marc_Doussain.JPG 2x" data-file-width="2951" data-file-height="4426" /></a><figcaption>An early 21st century <a href="/wiki/Mobile_phone" title="Mobile phone">mobile phone</a> being used for a phone call</figcaption></figure> <p>A typical phone call using a traditional phone is placed by picking the phone handset up off the base and holding the handset so that the hearing end is next to the user's ear and the speaking end is within range of the mouth. The caller then <a href="/wiki/Rotary_dial" title="Rotary dial">rotary dials</a> or presses buttons for the phone number needed to complete the call, and the call is routed to the phone which has that number. The second phone makes a ringing noise to alert its owner, while the user of the first phone hears a ringing noise in its earpiece. If the second phone is picked up, then the operators of the two units are able to talk to one another through them. If the phone is not picked up, the operator of the first phone continues to hear a ringing noise until they hang up their own phone. </p><p>In addition to the traditional method of placing a telephone call, new technologies allow different methods for initiating a telephone call, such as <a href="/wiki/Voice_dialing" class="mw-redirect" title="Voice dialing">voice dialing</a>. <a href="/wiki/Voice_over_IP" title="Voice over IP">Voice over IP</a> technology allows calls to be made through a <a href="/wiki/Personal_computer" title="Personal computer">PC</a>, using a service like <a href="/wiki/Skype" title="Skype">Skype</a>.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> Other services, such as toll-free dial-around enable callers to initiate a telephone call through a third party without exchanging phone numbers.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> Originally, no phone calls could be made without first talking to the <a href="/wiki/Switchboard_operator" title="Switchboard operator">Switchboard operator</a>. Using 21st century mobile phones does not require the use of an operator to complete a phone call. </p><p>The use of <a href="/wiki/Headset_(audio)" class="mw-redirect" title="Headset (audio)">headsets</a> is becoming more common for placing or receiving a call. Headsets can either come with a cord or be <a href="/wiki/Wireless" title="Wireless">wireless</a>. </p><p>A special number can be dialed for <a href="/wiki/Operator_assistance" title="Operator assistance">operator assistance</a>, which may be different for local vs. long-distance or international calls. </p> <div class="mw-heading mw-heading3"><h3 id="Details_of_operation">Details of operation</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Telephone_call&action=edit&section=5" title="Edit section: Details of operation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Telephoneschematic.gif" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b9/Telephoneschematic.gif/220px-Telephoneschematic.gif" decoding="async" width="220" height="123" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b9/Telephoneschematic.gif/330px-Telephoneschematic.gif 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b9/Telephoneschematic.gif/440px-Telephoneschematic.gif 2x" data-file-width="596" data-file-height="333" /></a><figcaption>Diagram</figcaption></figure> <p>The <a href="/wiki/Landline" title="Landline">landline telephone</a> contains a switchhook (A4) and an alerting device, usually a ringer (A7), that remains connected to the phone line whenever the phone is "<a href="/wiki/On_hook" class="mw-redirect" title="On hook">on hook</a>" (i.e. the switch (A4) is open), and other components which are connected when the phone is "<a href="/wiki/Off_hook" class="mw-redirect" title="Off hook">off hook</a>". The off-hook components include a transmitter (microphone, A2), a receiver (speaker, A1), and other circuits for dialing, filtering (A3), and amplification. </p><p>To place a telephone call, the <a href="/wiki/Calling_party" title="Calling party">calling party</a> picks up the telephone's handset, thereby operating a lever that closes the hook switch (A4). This powers the telephone by connecting the transmission hybrid transformer, as well as the transmitter (microphone) and receiver (speaker) to the line. In this off-hook state, the telephone circuitry has a low resistance of typically less than 300 <a href="/wiki/Ohm" title="Ohm">ohms</a>, which causes the flow of <a href="/wiki/Direct_current" title="Direct current">direct current</a> (DC) in the line (C) from the telephone exchange. The exchange detects this current, attaches a digit receiver circuit to the line, and sends <a href="/wiki/Dial_tone" title="Dial tone">dial tone</a> to indicate its readiness. On a modern <a href="/wiki/Push-button_telephone" title="Push-button telephone">push-button telephone</a>, the caller then presses the number keys to send the telephone number of the destination, the <a href="/wiki/Called_party" title="Called party">called party</a>. The keys control a tone generator circuit (not shown) that sends <a href="/wiki/DTMF" title="DTMF">DTMF</a> tones to the exchange. A <a href="/wiki/Rotary_dial" title="Rotary dial">rotary-dial telephone</a> uses <a href="/wiki/Pulse_dialing" title="Pulse dialing">pulse dialing</a> (A5), sending electrical pulses, that the exchange counts to decode each digit of the telephone number. If the called party's line is available, the terminating exchange applies an intermittent alternating current (AC) <a href="/wiki/Ringing_(telephony)" title="Ringing (telephony)">ringing signal</a> of 40 to 90 volts to alert the called party of the incoming call. If the called party's line is in use, however, the exchange returns a <a href="/wiki/Busy_signal" title="Busy signal">busy signal</a> to the calling party. If the called party's line is in use but subscribes to <a href="/wiki/Call_waiting" title="Call waiting">call waiting</a> service, the exchange sends an intermittent audible tone to the called party to indicate another call. </p><p>The electromechanical ringer of a telephone (A7) is connected to the line through a <a href="/wiki/Capacitor" title="Capacitor">capacitor</a> (A6), which blocks direct current and passes the alternating current of the ringing power. The telephone draws no current when it is on hook, while a DC voltage is continually applied to the line. Exchange circuitry (D2) can send an alternating current down the line to activate the ringer and announce an incoming call. In manual service exchange areas, before dial service was installed, telephones had hand-cranked <a href="/wiki/Telephone_magneto" title="Telephone magneto">magneto generators</a> to generate a ringing voltage back to the exchange or any other telephone on the same line. When a landline telephone is inactive (on hook), the circuitry at the telephone exchange detects the absence of direct current to indicate that the line is not in use.<sup id="cite_ref-EB1911_7-0" class="reference"><a href="#cite_note-EB1911-7"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> When a party initiates a call to this line, the exchange sends the ringing signal. When the called party picks up the handset, they actuate a double-circuit switchhook (not shown) which may simultaneously disconnect the alerting device and connect the audio circuitry to the line. This, in turn, draws direct current through the line, confirming that the called phone is now active. The exchange circuitry turns off the ring signal, and both telephones are now active and connected through the exchange. The parties may now converse as long as both phones remain off hook. When a party hangs up, placing the handset back on the cradle or hook, direct current ceases in that line, signaling the exchange to disconnect the call. </p><p>Calls to parties beyond the local exchange are carried over <a href="/wiki/Trunking" title="Trunking">trunk</a> lines which establish connections between exchanges. In modern telephone networks, <a href="/wiki/Fiber-optic_communication" title="Fiber-optic communication">fiber-optic cable</a> and <a href="/wiki/Digital_Multiplex_System" title="Digital Multiplex System">digital technology</a> are often employed in such connections. <a href="/wiki/Communications_satellite" title="Communications satellite">Satellite technology</a> may be used for communication over very long distances. </p><p>In most landline telephones, the transmitter and receiver (microphone and speaker) are located in the handset, although in a <a href="/wiki/Speakerphone" title="Speakerphone">speakerphone</a> these components may be located in the base or in a separate enclosure. Powered by the line, the microphone (A2) produces a modulated electric current which varies its <a href="/wiki/Frequency" title="Frequency">frequency</a> and <a href="/wiki/Amplitude" title="Amplitude">amplitude</a> in response to the <a href="/wiki/Sound" title="Sound">sound</a> waves arriving at its <a href="/wiki/Diaphragm_(acoustics)" title="Diaphragm (acoustics)">diaphragm</a>. The resulting current is transmitted along the telephone line to the local exchange then on to the other phone (via the local exchange or via a larger network), where it passes through the <a href="/wiki/Voice_coil" title="Voice coil">coil</a> of the receiver (A3). The varying current in the coil produces a corresponding movement of the receiver's diaphragm, <a href="/wiki/Reproduction" title="Reproduction">reproducing</a> the original sound waves present at the transmitter. </p><p>Along with the microphone and speaker, additional circuitry is incorporated to prevent the incoming speaker signal and the outgoing microphone signal from interfering with each other. This is accomplished through a <a href="/wiki/Hybrid_coil" class="mw-redirect" title="Hybrid coil">hybrid coil</a> (A3). The incoming audio signal passes through a resistor (A8) and the primary winding of the coil (A3) which passes it to the speaker (A1). Since the current path A8 – A3 has a far lower impedance than the microphone (A2), virtually all of the incoming signal passes through it and bypasses the microphone. </p><p>At the same time the DC voltage across the line causes a DC current which is split between the resistor-coil (A8-A3) branch and the microphone-coil (A2-A3) branch. The DC current through the resistor-coil branch has no effect on the incoming audio signal. But the DC current passing through the microphone is turned into AC (in response to voice sounds) which then passes through only the upper branch of the coil's (A3) primary winding, which has far fewer turns than the lower primary winding. This causes a small portion of the microphone output to be fed back to the speaker, while the rest of the AC goes out through the phone line. </p><p>A <a href="/wiki/Lineman%27s_handset" title="Lineman's handset">lineman's handset</a> is a telephone designed for testing the telephone network and may be attached directly to aerial lines and other infrastructure components. </p> <div class="mw-heading mw-heading2"><h2 id="Tones">Tones</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Telephone_call&action=edit&section=6" title="Edit section: Tones"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Preceding, during, and after a traditional telephone call is placed, certain <a href="/wiki/Call_progress_tone" class="mw-redirect" title="Call progress tone">tones</a> signify the progress and status of the telephone call: </p> <ul><li>a <a href="/wiki/Dial_tone" title="Dial tone">dial tone</a> signifying that the system is ready to accept a <a href="/wiki/Telephone_number" title="Telephone number">telephone number</a> and connect the call</li> <li>either: <ul><li>a <a href="/wiki/Ringback_tone" class="mw-redirect" title="Ringback tone">ringing tone</a> signifying that the called party has yet to answer the telephone</li> <li>a <a href="/wiki/Busy_signal_(telephony)" class="mw-redirect" title="Busy signal (telephony)">busy signal</a> (or engaged tone) signifying that the called party's telephone is being used in a telephone call to another person (or is "off the hook" though no number has been dialled, i.e. the customer does not want to be disturbed)</li> <li>a fast busy signal (also called <a href="/wiki/Reorder_tone" title="Reorder tone">reorder tone</a> or overflow busy tone) signifying that there is congestion in the telephone network, or possibly that the calling subscriber has delayed too long in dialling all the necessary digits. The fast busy signal is generally twice as fast as the normal busy signal.</li></ul></li> <li><a href="/wiki/Status_tones" class="mw-redirect" title="Status tones">status tones</a> such as STD notification tones (to inform the caller that the telephone call is being <a href="/wiki/Subscriber_trunk_dialling" title="Subscriber trunk dialling">trunk dialled</a> at a greater cost to the calling party), minute minder beeps (to inform the caller of the relative duration of the telephone call on calls that are charged on a time basis), and others</li> <li>a tone (sometimes the busy signal, often the dial tone) to signify that the called party has hung up.</li> <li>tones used by earlier <a href="/wiki/In-band_signaling" title="In-band signaling">inband</a> telephone switching systems were simulated by a Red box or a <a href="/wiki/Blue_box_(phreaking)" class="mw-redirect" title="Blue box (phreaking)">blue box</a> used by "<a href="/wiki/Phreaking" title="Phreaking">phone phreaks</a>" to illegally make or receive free trunk/toll calls.</li> <li><a href="/wiki/Off-hook_tone" title="Off-hook tone">off-hook tone</a> if the phone has been picked up but no number dialed for an extended period of time.</li></ul> <p><a href="/wiki/Cell_phone" class="mw-redirect" title="Cell phone">Cell phones</a> generally do not use dial tones, because the technology used to transmit the dialed number is different from a landline. </p> <div class="mw-heading mw-heading2"><h2 id="Unwanted_calls">Unwanted calls</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Telephone_call&action=edit&section=7" title="Edit section: Unwanted calls"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Nuisance_call" title="Nuisance call">Nuisance call</a></div> <p>Unsolicited telephone calls are a modern nuisance. Common kinds of unwanted calls include <a href="/wiki/Prank_call" title="Prank call">prank calls</a>, <a href="/wiki/Telemarketing" title="Telemarketing">telemarketing</a> calls, and <a href="/wiki/Obscene_phone_call" title="Obscene phone call">obscene phone calls</a>. </p><p>Caller ID provides some protection against unwanted calls, but can still be turned off by the calling party. Even where end-user Caller ID is not available, calls are still logged, both in billing records at the originating telco and via <a href="/wiki/Automatic_number_identification" title="Automatic number identification">automatic number identification</a>, so the perpetrator's phone number can still be discovered in many cases. However, this does not provide complete protection: harassers can use payphones, in some cases, automatic number identification itself can be spoofed or blocked, and mobile telephone abusers can (at some cost) use "throwaway" phones or SIMs. </p> <div class="mw-heading mw-heading2"><h2 id="Patents">Patents</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Telephone_call&action=edit&section=8" title="Edit section: Patents"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li>Rabinow, J., <span><a rel="nofollow" class="external text" href="https://patents.google.com/patent/US2813154">U.S. patent 2,813,154</a></span> - "<i>Telephone call indicator</i>"—November 12, 1957</li></ul> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Telephone_call&action=edit&section=9" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239009302">.mw-parser-output .portalbox{padding:0;margin:0.5em 0;display:table;box-sizing:border-box;max-width:175px;list-style:none}.mw-parser-output .portalborder{border:1px solid var(--border-color-base,#a2a9b1);padding:0.1em;background:var(--background-color-neutral-subtle,#f8f9fa)}.mw-parser-output .portalbox-entry{display:table-row;font-size:85%;line-height:110%;height:1.9em;font-style:italic;font-weight:bold}.mw-parser-output .portalbox-image{display:table-cell;padding:0.2em;vertical-align:middle;text-align:center}.mw-parser-output .portalbox-link{display:table-cell;padding:0.2em 0.2em 0.2em 0.3em;vertical-align:middle}@media(min-width:720px){.mw-parser-output .portalleft{clear:left;float:left;margin:0.5em 1em 0.5em 0}.mw-parser-output .portalright{clear:right;float:right;margin:0.5em 0 0.5em 1em}}</style><ul role="navigation" aria-label="Portals" class="noprint portalbox portalborder portalright"> <li class="portalbox-entry"><span class="portalbox-image"><span class="noviewer" typeof="mw:File"><span><img alt="telephone icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Telephone_icon_blue_gradient.svg/28px-Telephone_icon_blue_gradient.svg.png" decoding="async" width="28" height="28" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Telephone_icon_blue_gradient.svg/42px-Telephone_icon_blue_gradient.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Telephone_icon_blue_gradient.svg/56px-Telephone_icon_blue_gradient.svg.png 2x" data-file-width="722" data-file-height="722" /></span></span></span><span class="portalbox-link"><a href="/wiki/Portal:Telephones" title="Portal:Telephones">Telephones portal</a></span></li></ul> <ul><li><a href="/wiki/Call_completion" title="Call completion">Call completion</a></li> <li><a href="/wiki/Call_processing" title="Call processing">Call processing</a></li> <li><a href="/wiki/Emergency_telephone_number" title="Emergency telephone number">Emergency telephone number</a></li> <li><a href="/wiki/Pocket_dialing" title="Pocket dialing">Pocket dialing</a></li> <li><a href="/wiki/Telephone_phobia" title="Telephone phobia">Telephone phobia</a></li> <li><a href="/wiki/Teletraffic_engineering" title="Teletraffic engineering">Teletraffic engineering</a></li> <li><a href="/wiki/Video_call" class="mw-redirect" title="Video call">Video call</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Telephone_call&action=edit&section=10" title="Edit section: Notes"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-lower-alpha"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text">"Telcon" is also used as an abbreviation for <a href="/wiki/Telephone_conference" class="mw-redirect" title="Telephone conference">telephone conference</a>.<sup id="cite_ref-TELCON_1-1" class="reference"><a href="#cite_note-TELCON-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Telephone_call&action=edit&section=11" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style data-mw-deduplicate="TemplateStyles:r1237033735">@media print{body.ns-0 .mw-parser-output .sistersitebox{display:none!important}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}</style><div class="side-box side-box-right plainlinks sistersitebox"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style> <div class="side-box-flex"> <div class="side-box-image"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png" decoding="async" width="30" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/45px-Commons-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/59px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /></span></span></div> <div class="side-box-text plainlist">Wikimedia Commons has media related to <span style="font-weight: bold; font-style: italic;"><a href="https://commons.wikimedia.org/wiki/Category:People_on_telephone_calls" class="extiw" title="commons:Category:People on telephone calls">People on telephone calls</a></span>.</div></div> </div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239543626"><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-TELCON-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-TELCON_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-TELCON_1-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://acronyms.thefreedictionary.com/TELCON">"TELCON"</a>. <i>thefreedictionary.com</i>. Farlex, Inc<span class="reference-accessdate">. Retrieved <span class="nowrap">27 June</span> 2022</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=thefreedictionary.com&rft.atitle=TELCON&rft_id=https%3A%2F%2Facronyms.thefreedictionary.com%2FTELCON&rfr_id=info%3Asid%2Fen.wikipedia.org%3ATelephone+call" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFZagorsky2019" class="citation web cs1">Zagorsky, Jay L. (2019-03-14). <a rel="nofollow" class="external text" href="https://theconversation.com/rise-and-fall-of-the-landline-143-years-of-telephones-becoming-more-accessible-and-smart-113295">"Rise and fall of the landline: 143 years of telephones becoming more accessible – and smart"</a>. <i>The Conversation</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2023-05-20</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+Conversation&rft.atitle=Rise+and+fall+of+the+landline%3A+143+years+of+telephones+becoming+more+accessible+%E2%80%93+and+smart&rft.date=2019-03-14&rft.aulast=Zagorsky&rft.aufirst=Jay+L.&rft_id=http%3A%2F%2Ftheconversation.com%2Frise-and-fall-of-the-landline-143-years-of-telephones-becoming-more-accessible-and-smart-113295&rfr_id=info%3Asid%2Fen.wikipedia.org%3ATelephone+call" class="Z3988"></span></span> </li> <li id="cite_note-wired-4"><span class="mw-cite-backlink">^ <a href="#cite_ref-wired_4-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-wired_4-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAlfred2008" class="citation magazine cs1">Alfred, Randy (10 March 2008). <a rel="nofollow" class="external text" href="https://www.wired.com/science/discoveries/news/2008/03/dayintech_0310">"March 10, 1876: 'Mr. Watson, Come Here ... <span style="padding-right:0.15em;">'</span>"</a>. <i><a href="/wiki/Wired_(magazine)" title="Wired (magazine)">Wired</a></i><span class="reference-accessdate">. Retrieved <span class="nowrap">2013-03-18</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Wired&rft.atitle=March+10%2C+1876%3A+%27Mr.+Watson%2C+Come+Here+...+%3Cspan+style%3D%22padding-right%3A0.15em%3B%22%3E%26%2339%3B%3C%2Fspan%3E&rft.date=2008-03-10&rft.aulast=Alfred&rft.aufirst=Randy&rft_id=https%3A%2F%2Fwww.wired.com%2Fscience%2Fdiscoveries%2Fnews%2F2008%2F03%2Fdayintech_0310&rfr_id=info%3Asid%2Fen.wikipedia.org%3ATelephone+call" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRoos" class="citation web cs1">Roos, Dave. <a rel="nofollow" class="external text" href="http://computer.howstuffworks.com/ip-telephony9.htm">"How VoIP Works"</a>. How Stuff Works<span class="reference-accessdate">. Retrieved <span class="nowrap">12 March</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=How+VoIP+Works&rft.pub=How+Stuff+Works&rft.aulast=Roos&rft.aufirst=Dave&rft_id=http%3A%2F%2Fcomputer.howstuffworks.com%2Fip-telephony9.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3ATelephone+call" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.uwtcallback.com/otherSvcs/voip/how_it_works.html">"How VoIP Service Works"</a>. United World Telecom<span class="reference-accessdate">. Retrieved <span class="nowrap">20 February</span> 2014</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=How+VoIP+Service+Works&rft.pub=United+World+Telecom&rft_id=https%3A%2F%2Fwww.uwtcallback.com%2FotherSvcs%2Fvoip%2Fhow_it_works.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ATelephone+call" class="Z3988"></span></span> </li> <li id="cite_note-EB1911-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-EB1911_7-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKempeGarcke1911" class="citation encyclopaedia cs1">Kempe, Harry Robert; Garcke, Emile (1911). <span class="cs1-ws-icon" title="s:1911 Encyclopædia Britannica/Telephone"><a class="external text" href="https://en.wikisource.org/wiki/1911_Encyclop%C3%A6dia_Britannica/Telephone">"Telephone" </a></span>. In <a href="/wiki/Hugh_Chisholm" title="Hugh Chisholm">Chisholm, Hugh</a> (ed.). <i><a href="/wiki/Encyclop%C3%A6dia_Britannica_Eleventh_Edition" title="Encyclopædia Britannica Eleventh Edition">Encyclopædia Britannica</a></i>. Vol. 26 (11th ed.). Cambridge University Press. pp. 547–57.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Telephone&rft.btitle=Encyclop%C3%A6dia+Britannica&rft.pages=547-57&rft.edition=11th&rft.pub=Cambridge+University+Press&rft.date=1911&rft.aulast=Kempe&rft.aufirst=Harry+Robert&rft.au=Garcke%2C+Emile&rfr_id=info%3Asid%2Fen.wikipedia.org%3ATelephone+call" class="Z3988"></span></span> </li> </ol></div></div> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl 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.mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Telephony" style="padding:3px"><table class="nowraplinks mw-collapsible uncollapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Telephony" title="Template:Telephony"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Telephony" title="Template talk:Telephony"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Telephony" title="Special:EditPage/Template:Telephony"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Telephony" style="font-size:114%;margin:0 4em"><a href="/wiki/Telephony" title="Telephony">Telephony</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Types</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Landline" title="Landline">Landline</a></li> <li><a href="/wiki/Cable_telephony" title="Cable telephony">Cable telephony</a></li> <li><a href="/wiki/Mobile_phone" title="Mobile phone">Mobile phone</a></li> <li><a href="/wiki/Satellite_phone" title="Satellite phone">Satellite phone</a></li> <li><a href="/wiki/Photophone" title="Photophone">Photophone</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Accessories</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Answering_machine" title="Answering machine">Answering machine</a></li> <li><a href="/wiki/Caller_ID" title="Caller ID">Caller ID</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Connectivity</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Cable_protection_system" title="Cable protection system">Cable protection system</a></li> <li><a href="/wiki/Communications_satellite" title="Communications satellite">Communications satellites</a></li> <li><a href="/wiki/Fiber-optic_communication" title="Fiber-optic communication">Fibre-optical</a></li> <li><a href="/wiki/Free-space_optical_communication" title="Free-space optical communication">Free-space optical</a></li> <li><a href="/wiki/Integrated_Services_Digital_Network" class="mw-redirect" title="Integrated Services Digital Network">ISDN</a></li> <li><a href="/wiki/Mobile_phone_signal" title="Mobile phone signal">Mobile phone signal</a></li> <li><a href="/wiki/Plain_old_telephone_service" title="Plain old telephone service">POTS</a></li> <li><a href="/wiki/Public_switched_telephone_network" title="Public switched telephone network">PSTN</a></li> <li><a href="/wiki/Submarine_communications_cable" title="Submarine communications cable">Submarine cables</a></li> <li><a href="/wiki/Voice_over_IP" title="Voice over IP">VoIP</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Calls</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Missed_call" title="Missed call">Missed call</a></li> <li><a href="/wiki/Misdialed_call" title="Misdialed call">Misdialed call</a></li> <li><a href="/wiki/Nuisance_call" title="Nuisance call">Nuisance call</a></li> <li><a href="/wiki/Phone_tag" title="Phone tag">Phone tag</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Applications</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Fax" title="Fax">Fax transmission</a></li> <li><a class="mw-selflink selflink">Telephone calls</a></li> <li><a href="/wiki/Telephone_newspaper" title="Telephone newspaper">Telephone newspapers</a></li> <li><a href="/wiki/Th%C3%A9%C3%A2trophone" title="Théâtrophone">Théâtrophone</a></li> <li><a href="/wiki/Videotelephony" title="Videotelephony">Video calls</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div><span class="nowrap"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/28px-Telecom-icon.svg.png" decoding="async" width="28" height="28" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/42px-Telecom-icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/56px-Telecom-icon.svg.png 2x" data-file-width="500" data-file-height="500" /></span></span> </span><a href="/wiki/Portal:Telecommunication" title="Portal:Telecommunication">Telecommunication portal</a> <span class="nowrap"><span class="noviewer" typeof="mw:File"><span><img alt="telephone icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Telephone_icon_blue_gradient.svg/28px-Telephone_icon_blue_gradient.svg.png" decoding="async" width="28" height="28" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Telephone_icon_blue_gradient.svg/42px-Telephone_icon_blue_gradient.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Telephone_icon_blue_gradient.svg/56px-Telephone_icon_blue_gradient.svg.png 2x" data-file-width="722" data-file-height="722" /></span></span> </span><a href="/wiki/Portal:Telephones" title="Portal:Telephones">Telephones portal</a></div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Telecommunications" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Telecommunications" title="Template:Telecommunications"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Telecommunications" title="Template talk:Telecommunications"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Telecommunications" title="Special:EditPage/Template:Telecommunications"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Telecommunications" style="font-size:114%;margin:0 4em"><a href="/wiki/Telecommunications" title="Telecommunications">Telecommunications</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/History_of_telecommunication" title="History of telecommunication">History</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Beacon#For_defensive_communications" title="Beacon">Beacon</a></li> <li><a href="/wiki/History_of_broadcasting" title="History of broadcasting">Broadcasting</a></li> <li><a href="/wiki/Cable_protection_system" title="Cable protection system">Cable protection system</a></li> <li><a href="/wiki/Cable_television" title="Cable television">Cable TV</a></li> <li><a href="/wiki/Communications_satellite#History" title="Communications satellite">Communications satellite</a></li> <li><a href="/wiki/Computer_network#History" title="Computer network">Computer network</a></li> <li><a href="/wiki/Data_compression" title="Data compression">Data compression</a> <ul><li><a href="/wiki/Audio_coding_format" title="Audio coding format">audio</a></li> <li><a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">DCT</a></li> <li><a href="/wiki/Image_compression" title="Image compression">image</a></li> <li><a href="/wiki/Video_coding_format" title="Video coding format">video</a></li></ul></li> <li><a href="/wiki/Digital_media" title="Digital media">Digital media</a> <ul><li><a href="/wiki/Internet_video" title="Internet video">Internet video</a></li> <li><a href="/wiki/Online_video_platform" title="Online video platform">online video platform</a></li> <li><a href="/wiki/Social_media" title="Social media">social media</a></li> <li><a href="/wiki/Streaming_media" title="Streaming media">streaming</a></li></ul></li> <li><a href="/wiki/Drums_in_communication" title="Drums in communication">Drums</a></li> <li><a href="/wiki/Edholm%27s_law" title="Edholm's law">Edholm's law</a></li> <li><a href="/wiki/Electrical_telegraph#History" title="Electrical telegraph">Electrical telegraph</a></li> <li><a href="/wiki/Fax#History" title="Fax">Fax</a></li> <li><a href="/wiki/Heliograph#History" title="Heliograph">Heliographs</a></li> <li><a href="/wiki/Hydraulic_telegraph#Greek_hydraulic_semaphore_system" title="Hydraulic telegraph">Hydraulic telegraph</a></li> <li><a href="/wiki/Information_Age" title="Information Age">Information Age</a></li> <li><a href="/wiki/Information_revolution" class="mw-redirect" title="Information revolution">Information revolution</a></li> <li><a href="/wiki/History_of_the_Internet" title="History of the Internet">Internet</a></li> <li><a href="/wiki/Mass_media#History" title="Mass media">Mass media</a></li> <li><a href="/wiki/History_of_mobile_phones" title="History of mobile phones">Mobile phone</a> <ul><li><a href="/wiki/Smartphone" title="Smartphone">Smartphone</a></li></ul></li> <li><a href="/wiki/Optical_communication" title="Optical communication">Optical telecommunication</a></li> <li><a href="/wiki/Optical_telegraph" title="Optical telegraph">Optical telegraphy</a></li> <li><a href="/wiki/Pager" title="Pager">Pager</a></li> <li><a href="/wiki/Photophone" title="Photophone">Photophone</a></li> <li><a href="/wiki/History_of_prepaid_mobile_phones" title="History of prepaid mobile phones">Prepaid mobile phone</a></li> <li><a href="/wiki/History_of_radio" title="History of radio">Radio</a></li> <li><a href="/wiki/Radiotelephone" title="Radiotelephone">Radiotelephone</a></li> <li><a href="/wiki/Communications_satellite" title="Communications satellite">Satellite communications</a></li> <li><a href="/wiki/Semaphore" title="Semaphore">Semaphore</a> <ul><li><a href="/wiki/Phryctoria" title="Phryctoria">Phryctoria</a></li></ul></li> <li><a href="/wiki/Semiconductor" title="Semiconductor">Semiconductor</a> <ul><li><a href="/wiki/Semiconductor_device" title="Semiconductor device">device</a></li> <li><a href="/wiki/MOSFET" title="MOSFET">MOSFET</a></li> <li><a href="/wiki/History_of_the_transistor" title="History of the transistor">transistor</a></li></ul></li> <li><a href="/wiki/Smoke_signal" title="Smoke signal">Smoke signals</a></li> <li><a href="/wiki/History_of_telecommunication" title="History of telecommunication">Telecommunications history</a></li> <li><a href="/wiki/Telautograph" title="Telautograph">Telautograph</a></li> <li><a href="/wiki/Telegraphy" title="Telegraphy">Telegraphy</a></li> <li><a href="/wiki/Teleprinter" title="Teleprinter">Teleprinter</a> (teletype)</li> <li><a href="/wiki/History_of_the_telephone" title="History of the telephone">Telephone</a></li> <li><i><a href="/wiki/The_Telephone_Cases" title="The Telephone Cases">The Telephone Cases</a></i></li> <li><a href="/wiki/History_of_television" title="History of television">Television</a> <ul><li><a href="/wiki/Digital_television" title="Digital television">digital</a></li> <li><a href="/wiki/Streaming_television" title="Streaming television">streaming</a></li></ul></li> <li><a href="/wiki/Submarine_communications_cable#Early_history:_telegraph_and_coaxial_cables" title="Submarine communications cable">Undersea telegraph line</a></li> <li><a href="/wiki/History_of_videotelephony" title="History of videotelephony">Videotelephony</a></li> <li><a href="/wiki/Whistled_language" title="Whistled language">Whistled language</a></li> <li><a href="/wiki/Wireless_revolution" class="mw-redirect" title="Wireless revolution">Wireless revolution</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Pioneers</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Nasir_Ahmed_(engineer)" title="Nasir Ahmed (engineer)">Nasir Ahmed</a></li> <li><a href="/wiki/Edwin_Howard_Armstrong" title="Edwin Howard Armstrong">Edwin Howard Armstrong</a></li> <li><a href="/wiki/Mohamed_M._Atalla" title="Mohamed M. Atalla">Mohamed M. Atalla</a></li> <li><a href="/wiki/John_Logie_Baird" title="John Logie Baird">John Logie Baird</a></li> <li><a href="/wiki/Paul_Baran" title="Paul Baran">Paul Baran</a></li> <li><a href="/wiki/John_Bardeen" title="John Bardeen">John Bardeen</a></li> <li><a href="/wiki/Alexander_Graham_Bell" title="Alexander Graham Bell">Alexander Graham Bell</a></li> <li><a href="/wiki/Emile_Berliner" title="Emile Berliner">Emile Berliner</a></li> <li><a href="/wiki/Tim_Berners-Lee" title="Tim Berners-Lee">Tim Berners-Lee</a></li> <li><a href="/wiki/Francis_Blake_(inventor)" title="Francis Blake (inventor)">Francis Blake</a></li> <li><a href="/wiki/Jagadish_Chandra_Bose" title="Jagadish Chandra Bose">Jagadish Chandra Bose</a></li> <li><a href="/wiki/Charles_Bourseul" title="Charles Bourseul">Charles Bourseul</a></li> <li><a href="/wiki/Walter_Houser_Brattain" title="Walter Houser Brattain">Walter Houser Brattain</a></li> <li><a href="/wiki/Vint_Cerf" title="Vint Cerf">Vint Cerf</a></li> <li><a href="/wiki/Claude_Chappe" title="Claude Chappe">Claude Chappe</a></li> <li><a href="/wiki/Yogen_Dalal" class="mw-redirect" title="Yogen Dalal">Yogen Dalal</a></li> <li><a href="/wiki/Daniel_Davis_Jr." title="Daniel Davis Jr.">Daniel Davis Jr.</a></li> <li><a href="/wiki/Donald_Davies" title="Donald Davies">Donald Davies</a></li> <li><a href="/wiki/Amos_Dolbear" title="Amos Dolbear">Amos Dolbear</a></li> <li><a href="/wiki/Thomas_Edison" title="Thomas Edison">Thomas Edison</a></li> <li><a href="/wiki/Lee_de_Forest" title="Lee de Forest">Lee de Forest</a></li> <li><a href="/wiki/Philo_Farnsworth" title="Philo Farnsworth">Philo Farnsworth</a></li> <li><a href="/wiki/Reginald_Fessenden" title="Reginald Fessenden">Reginald Fessenden</a></li> <li><a href="/wiki/Elisha_Gray" title="Elisha Gray">Elisha Gray</a></li> <li><a href="/wiki/Oliver_Heaviside" title="Oliver Heaviside">Oliver Heaviside</a></li> <li><a href="/wiki/Robert_Hooke" title="Robert Hooke">Robert Hooke</a></li> <li><a href="/wiki/Erna_Schneider_Hoover" title="Erna Schneider Hoover">Erna Schneider Hoover</a></li> <li><a href="/wiki/Harold_Hopkins_(physicist)" title="Harold Hopkins (physicist)">Harold Hopkins</a></li> <li><a href="/wiki/Gardiner_Greene_Hubbard" title="Gardiner Greene Hubbard">Gardiner Greene Hubbard</a></li> <li><a href="/wiki/List_of_Internet_pioneers" title="List of Internet pioneers">Internet pioneers</a></li> <li><a href="/wiki/Bob_Kahn" class="mw-redirect" title="Bob Kahn">Bob Kahn</a></li> <li><a href="/wiki/Dawon_Kahng" title="Dawon Kahng">Dawon Kahng</a></li> <li><a href="/wiki/Charles_K._Kao" title="Charles K. Kao">Charles K. Kao</a></li> <li><a href="/wiki/Narinder_Singh_Kapany" title="Narinder Singh Kapany">Narinder Singh Kapany</a></li> <li><a href="/wiki/Hedy_Lamarr" title="Hedy Lamarr">Hedy Lamarr</a></li> <li><a href="/wiki/Roberto_Landell_de_Moura" title="Roberto Landell de Moura">Roberto Landell de Moura</a></li> <li><a href="/wiki/Innocenzo_Manzetti" title="Innocenzo Manzetti">Innocenzo Manzetti</a></li> <li><a href="/wiki/Guglielmo_Marconi" title="Guglielmo Marconi">Guglielmo Marconi</a></li> <li><a href="/wiki/Robert_Metcalfe" title="Robert Metcalfe">Robert Metcalfe</a></li> <li><a href="/wiki/Antonio_Meucci" title="Antonio Meucci">Antonio Meucci</a></li> <li><a href="/wiki/Samuel_Morse" title="Samuel Morse">Samuel Morse</a></li> <li><a href="/wiki/Jun-ichi_Nishizawa" title="Jun-ichi Nishizawa">Jun-ichi Nishizawa</a></li> <li><a href="/wiki/Charles_Grafton_Page" title="Charles Grafton Page">Charles Grafton Page</a></li> <li><a href="/wiki/Radia_Perlman" title="Radia Perlman">Radia Perlman</a></li> <li><a href="/wiki/Alexander_Stepanovich_Popov" class="mw-redirect" title="Alexander Stepanovich Popov">Alexander Stepanovich Popov</a></li> <li><a href="/wiki/Tivadar_Pusk%C3%A1s" title="Tivadar Puskás">Tivadar Puskás</a></li> <li><a href="/wiki/Johann_Philipp_Reis" title="Johann Philipp Reis">Johann Philipp Reis</a></li> <li><a href="/wiki/Claude_Shannon" title="Claude Shannon">Claude Shannon</a></li> <li><a href="/wiki/Almon_Brown_Strowger" title="Almon Brown Strowger">Almon Brown Strowger</a></li> <li><a href="/wiki/Henry_Sutton_(inventor)" title="Henry Sutton (inventor)">Henry Sutton</a></li> <li><a href="/wiki/Charles_Sumner_Tainter" title="Charles Sumner Tainter">Charles Sumner Tainter</a></li> <li><a href="/wiki/Nikola_Tesla" title="Nikola Tesla">Nikola Tesla</a></li> <li><a href="/wiki/Camille_Tissot" title="Camille Tissot">Camille Tissot</a></li> <li><a href="/wiki/Alfred_Vail" title="Alfred Vail">Alfred Vail</a></li> <li><a href="/wiki/Thomas_A._Watson" title="Thomas A. Watson">Thomas A. Watson</a></li> <li><a href="/wiki/Charles_Wheatstone" title="Charles Wheatstone">Charles Wheatstone</a></li> <li><a href="/wiki/Vladimir_K._Zworykin" title="Vladimir K. Zworykin">Vladimir K. Zworykin</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Transmission_medium" title="Transmission medium">Transmission<br />media</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Coaxial_cable" title="Coaxial cable">Coaxial cable</a></li> <li><a href="/wiki/Fiber-optic_communication" title="Fiber-optic communication">Fiber-optic communication</a> <ul><li><a href="/wiki/Optical_fiber" title="Optical fiber">optical fiber</a></li></ul></li> <li><a href="/wiki/Free-space_optical_communication" title="Free-space optical communication">Free-space optical communication</a></li> <li><a href="/wiki/Molecular_communication" title="Molecular communication">Molecular communication</a></li> <li><a href="/wiki/Radio_wave" title="Radio wave">Radio waves</a> <ul><li><a href="/wiki/Wireless" title="Wireless">wireless</a></li></ul></li> <li><a href="/wiki/Transmission_line" title="Transmission line">Transmission line</a> <ul><li><a href="/wiki/Telecommunication_circuit" title="Telecommunication circuit">telecommunication circuit</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Network_topology" title="Network topology">Network topology</a><br />and switching</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Bandwidth_(computing)" title="Bandwidth (computing)">Bandwidth</a></li> <li><a href="/wiki/Telecommunications_link" title="Telecommunications link">Links</a></li> <li><a href="/wiki/Node_(networking)" title="Node (networking)">Nodes</a> <ul><li><a href="/wiki/Terminal_(telecommunication)" title="Terminal (telecommunication)">terminal</a></li></ul></li> <li><a href="/wiki/Network_switch" title="Network switch">Network switching</a> <ul><li><a href="/wiki/Circuit_switching" title="Circuit switching">circuit</a></li> <li><a href="/wiki/Packet_switching" title="Packet switching">packet</a></li></ul></li> <li><a href="/wiki/Telephone_exchange" title="Telephone exchange">Telephone exchange</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Multiplexing" title="Multiplexing">Multiplexing</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Space-division_multiple_access" title="Space-division multiple access">Space-division</a></li> <li><a href="/wiki/Frequency-division_multiplexing" title="Frequency-division multiplexing">Frequency-division</a></li> <li><a href="/wiki/Time-division_multiplexing" title="Time-division multiplexing">Time-division</a></li> <li><a href="/wiki/Polarization-division_multiplexing" title="Polarization-division multiplexing">Polarization-division</a></li> <li><a href="/wiki/Orbital_angular_momentum_multiplexing" title="Orbital angular momentum multiplexing">Orbital angular-momentum</a></li> <li><a href="/wiki/Code-division_multiple_access" title="Code-division multiple access">Code-division</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Concepts</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Communication_protocol" title="Communication protocol">Communication protocol</a></li> <li><a href="/wiki/Computer_network" title="Computer network">Computer network</a></li> <li><a href="/wiki/Data_communication" title="Data communication">Data transmission</a></li> <li><a href="/wiki/Store_and_forward" title="Store and forward">Store and forward</a></li> <li><a href="/wiki/Telecommunications_equipment" title="Telecommunications equipment">Telecommunications equipment</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Telecommunications_network" title="Telecommunications network">Types of network</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Cellular_network" title="Cellular network">Cellular network</a></li> <li><a href="/wiki/Ethernet" title="Ethernet">Ethernet</a></li> <li><a href="/wiki/Integrated_Services_Digital_Network" class="mw-redirect" title="Integrated Services Digital Network">ISDN</a></li> <li><a href="/wiki/Local_area_network" title="Local area network">LAN</a></li> <li><a href="/wiki/Mobile_telephony" title="Mobile telephony">Mobile</a></li> <li><a href="/wiki/Next-generation_network" title="Next-generation network">NGN</a></li> <li><a href="/wiki/Public_switched_telephone_network" title="Public switched telephone network">Public Switched Telephone</a></li> <li><a href="/wiki/Radio_network" title="Radio network">Radio</a></li> <li><a href="/wiki/Television_broadcasting" class="mw-redirect" title="Television broadcasting">Television</a></li> <li><a href="/wiki/Telex" title="Telex">Telex</a></li> <li><a href="/wiki/UUCP" title="UUCP">UUCP</a></li> <li><a href="/wiki/Wide_area_network" title="Wide area network">WAN</a></li> <li><a href="/wiki/Wireless_network" title="Wireless network">Wireless network</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Telecommunications_network" title="Telecommunications network">Notable networks</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ARPANET" title="ARPANET">ARPANET</a></li> <li><a href="/wiki/BITNET" title="BITNET">BITNET</a></li> <li><a href="/wiki/CYCLADES" title="CYCLADES">CYCLADES</a></li> <li><a href="/wiki/FidoNet" title="FidoNet">FidoNet</a></li> <li><a href="/wiki/Internet" title="Internet">Internet</a></li> <li><a href="/wiki/Internet2" title="Internet2">Internet2</a></li> <li><a href="/wiki/JANET" title="JANET">JANET</a></li> <li><a href="/wiki/NPL_network" title="NPL network">NPL network</a></li> <li><a href="/wiki/Toasternet" title="Toasternet">Toasternet</a></li> <li><a href="/wiki/Usenet" title="Usenet">Usenet</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Locations</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Category:Telecommunications_in_Africa" title="Category:Telecommunications in Africa">Africa</a></li> <li>Americas <ul><li><a href="/wiki/Category:Telecommunications_in_North_America" title="Category:Telecommunications in North America">North</a></li> <li><a href="/wiki/Category:Telecommunications_in_South_America" title="Category:Telecommunications in South America">South</a></li></ul></li> <li><a href="/wiki/Category:Communications_in_Antarctica" title="Category:Communications in Antarctica">Antarctica</a></li> <li><a href="/wiki/Category:Telecommunications_in_Asia" title="Category:Telecommunications in Asia">Asia</a></li> <li><a href="/wiki/Category:Telecommunications_in_Europe" title="Category:Telecommunications in Europe">Europe</a></li> <li><a href="/wiki/Category:Telecommunications_in_Oceania" title="Category:Telecommunications in Oceania">Oceania</a></li> <li>(<a href="/wiki/List_of_telecommunications_regulatory_bodies" title="List of telecommunications regulatory bodies">Global telecommunications regulation bodies</a>)</li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="nowrap"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/16px-Telecom-icon.svg.png" decoding="async" width="16" height="16" class="mw-file-element" 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