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</li> <li id="toc-Full-duplex_emulation" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Full-duplex_emulation"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Full-duplex emulation</span> </div> </a> <button aria-controls="toc-Full-duplex_emulation-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 Full-duplex emulation subsection</span> </button> <ul id="toc-Full-duplex_emulation-sublist" class="vector-toc-list"> <li id="toc-Time-division_duplexing" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Time-division_duplexing"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Time-division duplexing</span> </div> </a> <ul id="toc-Time-division_duplexing-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Frequency-division_duplexing" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Frequency-division_duplexing"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>Frequency-division duplexing</span> </div> </a> <ul id="toc-Frequency-division_duplexing-sublist" class="vector-toc-list"> </ul> </li> </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">5</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">6</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">7</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>Further reading</span> </div> </a> <ul id="toc-Further_reading-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" > 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mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 30 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-30" 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">30 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/%D8%A7%D8%B2%D8%AF%D9%88%D8%A7%D8%AC_(%D8%A7%D8%AA%D8%B5%D8%A7%D9%84%D8%A7%D8%AA)" title="ازدواج (اتصالات) – Arabic" lang="ar" hreflang="ar" data-title="ازدواج (اتصالات)" 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/D%C3%BAplex_(telecomunicacions)" title="Dúplex (telecomunicacions) – Catalan" lang="ca" hreflang="ca" data-title="Dúplex (telecomunicacions)" 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/Duplexn%C3%AD_spojen%C3%AD" title="Duplexní spojení – Czech" lang="cs" hreflang="cs" data-title="Duplexní spojení" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Dupleks_(kommunikation)" title="Dupleks (kommunikation) – Danish" lang="da" hreflang="da" data-title="Dupleks (kommunikation)" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Duplex_(Nachrichtentechnik)" title="Duplex (Nachrichtentechnik) – German" lang="de" hreflang="de" data-title="Duplex (Nachrichtentechnik)" 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/Dupleks" title="Dupleks – Estonian" lang="et" hreflang="et" data-title="Dupleks" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/D%C3%BAplex_(telecomunicaciones)" title="Dúplex (telecomunicaciones) – Spanish" lang="es" hreflang="es" data-title="Dúplex (telecomunicaciones)" 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/Duplex_(telekomunikazioa)" title="Duplex (telekomunikazioa) – Basque" lang="eu" hreflang="eu" data-title="Duplex (telekomunikazioa)" 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%AF%D9%88%D8%B7%D8%B1%D9%81%D9%87_(%D9%85%D8%AE%D8%A7%D8%A8%D8%B1%D8%A7%D8%AA)" title="دوطرفه (مخابرات) – Persian" lang="fa" hreflang="fa" data-title="دوطرفه (مخابرات)" 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/Duplex_(canal_de_communication)" title="Duplex (canal de communication) – French" lang="fr" hreflang="fr" data-title="Duplex (canal de communication)" 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/Full_duplex" title="Full duplex – Galician" lang="gl" hreflang="gl" data-title="Full duplex" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EC%9D%B4%EC%A4%91%ED%86%B5%EC%8B%A0" title="이중통신 – Korean" lang="ko" hreflang="ko" data-title="이중통신" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Duplex" title="Duplex – Indonesian" lang="id" hreflang="id" data-title="Duplex" 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-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Duplex" title="Duplex – Italian" lang="it" hreflang="it" data-title="Duplex" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%AA%D7%A7%D7%A9%D7%95%D7%A8%D7%AA_%D7%93%D7%95_%D7%9B%D7%99%D7%95%D7%95%D7%A0%D7%99%D7%AA_(%D7%93%D7%95%D7%A4%D7%9C%D7%A7%D7%A1)" title="תקשורת דו כיוונית (דופלקס) – Hebrew" lang="he" hreflang="he" data-title="תקשורת דו כיוונית (דופלקס)" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D0%94%D1%83%D0%BF%D0%BB%D0%B5%D0%BA%D1%81%D1%82%D1%96_%D0%B1%D0%B0%D0%B9%D0%BB%D0%B0%D0%BD%D1%8B%D1%81" title="Дуплексті байланыс – Kazakh" lang="kk" hreflang="kk" data-title="Дуплексті байланыс" data-language-autonym="Қазақша" data-language-local-name="Kazakh" class="interlanguage-link-target"><span>Қазақша</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Full-duplex" title="Full-duplex – Dutch" lang="nl" hreflang="nl" data-title="Full-duplex" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E8%A4%87%E4%BF%A1" title="複信 – Japanese" lang="ja" hreflang="ja" data-title="複信" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Dupleks_(kommunikasjonsteknologi)" title="Dupleks (kommunikasjonsteknologi) – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Dupleks (kommunikasjonsteknologi)" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-uz mw-list-item"><a href="https://uz.wikipedia.org/wiki/Dupleks_aloqa" title="Dupleks aloqa – Uzbek" lang="uz" hreflang="uz" data-title="Dupleks aloqa" data-language-autonym="Oʻzbekcha / ўзбекча" data-language-local-name="Uzbek" class="interlanguage-link-target"><span>Oʻzbekcha / ўзбекча</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Dupleks_(telekomunikacja)" title="Dupleks (telekomunikacja) – Polish" lang="pl" hreflang="pl" data-title="Dupleks (telekomunikacja)" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Duplex" title="Duplex – Portuguese" lang="pt" hreflang="pt" data-title="Duplex" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%94%D1%83%D0%BF%D0%BB%D0%B5%D0%BA%D1%81_(%D1%82%D0%B5%D0%BB%D0%B5%D0%BA%D0%BE%D0%BC%D0%BC%D1%83%D0%BD%D0%B8%D0%BA%D0%B0%D1%86%D0%B8%D0%B8)" title="Дуплекс (телекоммуникации) – Russian" lang="ru" hreflang="ru" data-title="Дуплекс (телекоммуникации)" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%94%D1%83%D0%BF%D0%BB%D0%B5%D0%BA%D1%81_%D0%BA%D0%BE%D0%BC%D1%83%D0%BD%D0%B8%D0%BA%D0%B0%D1%86%D0%B8%D1%98%D0%B0" title="Дуплекс комуникација – Serbian" lang="sr" hreflang="sr" data-title="Дуплекс комуникација" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-su mw-list-item"><a href="https://su.wikipedia.org/wiki/Duplex" title="Duplex – Sundanese" lang="su" hreflang="su" data-title="Duplex" data-language-autonym="Sunda" data-language-local-name="Sundanese" class="interlanguage-link-target"><span>Sunda</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Duplex" title="Duplex – Finnish" lang="fi" hreflang="fi" data-title="Duplex" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Duplex_(kommunikation)" title="Duplex (kommunikation) – Swedish" lang="sv" hreflang="sv" data-title="Duplex (kommunikation)" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%94%D1%83%D0%BF%D0%BB%D0%B5%D0%BA%D1%81_(%D1%82%D0%B5%D0%BB%D0%B5%D0%BA%D0%BE%D0%BC%D1%83%D0%BD%D1%96%D0%BA%D0%B0%D1%86%D1%96%D1%97)" title="Дуплекс (телекомунікації) – Ukrainian" lang="uk" hreflang="uk" data-title="Дуплекс (телекомунікації)" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Song_c%C3%B4ng" title="Song công – Vietnamese" lang="vi" hreflang="vi" data-title="Song công" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E9%9B%99%E5%B7%A5" title="雙工 – Chinese" lang="zh" hreflang="zh" data-title="雙工" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q625306#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div 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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-More_footnotes_needed plainlinks metadata ambox ambox-style ambox-More_footnotes_needed" 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/a/a4/Text_document_with_red_question_mark.svg/40px-Text_document_with_red_question_mark.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a4/Text_document_with_red_question_mark.svg/60px-Text_document_with_red_question_mark.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a4/Text_document_with_red_question_mark.svg/80px-Text_document_with_red_question_mark.svg.png 2x" data-file-width="48" data-file-height="48" /></span></span></div></td><td class="mbox-text"><div class="mbox-text-span">This article includes a list of <a href="/wiki/Wikipedia:Citing_sources#General_references" title="Wikipedia:Citing sources">general references</a>, but <b>it lacks sufficient corresponding <a href="/wiki/Wikipedia:Citing_sources#Inline_citations" title="Wikipedia:Citing sources">inline citations</a></b>.<span class="hide-when-compact"> Please help to <a href="/wiki/Wikipedia:WikiProject_Reliability" title="Wikipedia:WikiProject Reliability">improve</a> this article by <a href="/wiki/Wikipedia:When_to_cite" title="Wikipedia:When to cite">introducing</a> more precise citations.</span> <span class="date-container"><i>(<span class="date">September 2015</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <p>A <b>duplex</b> <a href="/wiki/Communication_system" class="mw-redirect" title="Communication system">communication system</a> is a <a href="/wiki/Point-to-point_(telecommunications)" title="Point-to-point (telecommunications)">point-to-point</a> system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow for simultaneous communication in both directions between two connected parties or to provide a reverse path for the monitoring and remote adjustment of equipment in the field. There are two types of duplex communication systems: full-duplex (FDX) and half-duplex (HDX). </p><p>In a <b>full-duplex</b> system, both parties can communicate with each other simultaneously. An example of a full-duplex device is <a href="/wiki/Plain_old_telephone_service" title="Plain old telephone service">plain old telephone service</a>; the parties at both ends of a call can speak and be heard by the other party simultaneously. The earphone reproduces the speech of the remote party as the microphone transmits the speech of the local party. There is a two-way communication channel between them, or more strictly speaking, there are two communication channels between them. </p><p>In a <b>half-duplex</b> or <b>semiduplex</b> system, both parties can communicate with each other, but not simultaneously; the communication is one direction at a time. An example of a half-duplex device is a <a href="/wiki/Walkie-talkie" title="Walkie-talkie">walkie-talkie</a>, a <a href="/wiki/Two-way_radio" title="Two-way radio">two-way radio</a> that has a <a href="/wiki/Push-to-talk" title="Push-to-talk">push-to-talk</a> button. When the local user wants to speak to the remote person, they push this button, which turns on the transmitter and turns off the receiver, preventing them from hearing the remote person while talking. To listen to the remote person, they release the button, which turns on the receiver and turns off the transmitter. This terminology is not completely standardized, and some sources define this mode as <a href="/wiki/Simplex_communication" class="mw-redirect" title="Simplex communication">simplex</a>.<sup id="cite_ref-Lindley_1-0" class="reference"><a href="#cite_note-Lindley-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Gosling_2-0" class="reference"><a href="#cite_note-Gosling-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </p><p>Systems that do not need duplex capability may instead use <a href="/wiki/Simplex_communication" class="mw-redirect" title="Simplex communication">simplex communication</a>, in which one device transmits and the others can only listen. Examples are <a href="/wiki/Broadcast" class="mw-redirect" title="Broadcast">broadcast</a> radio and television, <a href="/wiki/Garage_door_opener" title="Garage door opener">garage door openers</a>, <a href="/wiki/Baby_monitor" title="Baby monitor">baby monitors</a>, <a href="/wiki/Wireless_microphone" title="Wireless microphone">wireless microphones</a>, and <a href="/wiki/Surveillance_camera" class="mw-redirect" title="Surveillance camera">surveillance cameras</a>. In these devices, the communication is only in one direction. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Simplex">Simplex</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Duplex_(telecommunications)&action=edit&section=1" title="Edit section: Simplex"><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:Simplex.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/7c/Simplex.jpg/220px-Simplex.jpg" decoding="async" width="220" height="100" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/7c/Simplex.jpg/330px-Simplex.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/7c/Simplex.jpg/440px-Simplex.jpg 2x" data-file-width="576" data-file-height="261" /></a><figcaption>Simplex wireless communication</figcaption></figure> <p><b>Simplex communication</b> is a <a href="/wiki/Communication_channel" title="Communication channel">communication channel</a> that sends information in one direction only.<sup id="cite_ref-IEEE_3-0" class="reference"><a href="#cite_note-IEEE-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p><p>The <a href="/wiki/International_Telecommunication_Union" title="International Telecommunication Union">International Telecommunication Union</a> definition is a communications channel that operates in one direction at a time, but that may be reversible; this is termed <i><a href="/wiki/Half_duplex" class="mw-redirect" title="Half duplex">half duplex</a></i> in other contexts. </p><p>For example, in TV and radio <a href="/wiki/Broadcasting" title="Broadcasting">broadcasting</a>, information flows only from the transmitter site to multiple receivers. A pair of <a href="/wiki/Walkie-talkie" title="Walkie-talkie">walkie-talkie</a> <a href="/wiki/Two-way_radio" title="Two-way radio">two-way radios</a> provide a simplex circuit in the ITU sense; only one party at a time can talk, while the other listens until it can hear an opportunity to transmit. The transmission medium (the radio signal over the air) can carry information in only one direction. </p><p>The <a href="/wiki/Western_Union" title="Western Union">Western Union</a> company used the term <i>simplex</i> when describing the half-duplex and simplex capacity of their new <a href="/wiki/Transatlantic_telegraph_cable" title="Transatlantic telegraph cable">transatlantic telegraph cable</a> completed between <a href="/wiki/Newfoundland_(island)" title="Newfoundland (island)">Newfoundland</a> and the <a href="/wiki/Azores" title="Azores">Azores</a> in 1928.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> The same definition for a simplex radio channel was used by the <a href="/wiki/National_Fire_Protection_Association" title="National Fire Protection Association">National Fire Protection Association</a> in 2002.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Half_duplex"><span class="anchor" id="HALF-DUPLEX"></span><span class="anchor" id="Half-duplex"></span>Half duplex</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Duplex_(telecommunications)&action=edit&section=2" title="Edit section: Half duplex"><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:HalfDuplex.JPG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b3/HalfDuplex.JPG/220px-HalfDuplex.JPG" decoding="async" width="220" height="150" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b3/HalfDuplex.JPG/330px-HalfDuplex.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b3/HalfDuplex.JPG/440px-HalfDuplex.JPG 2x" data-file-width="462" data-file-height="316" /></a><figcaption>A simple illustration of a half-duplex communication system</figcaption></figure> <p>A <b>half-duplex</b> (<b>HDX</b>) system provides communication in both directions, but only one direction at a time, not simultaneously in both directions.<sup id="cite_ref-Sudakshina_6-0" class="reference"><a href="#cite_note-Sudakshina-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> <sup id="cite_ref-Frenzel_7-0" class="reference"><a href="#cite_note-Frenzel-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-ITU_8-0" class="reference"><a href="#cite_note-ITU-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> This terminology is not completely standardized between defining organizations, and in radio communication some sources classify this mode as <i><a href="/wiki/Simplex_communication" class="mw-redirect" title="Simplex communication">simplex</a></i>.<sup id="cite_ref-Gosling_2-1" class="reference"><a href="#cite_note-Gosling-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> <sup id="cite_ref-Lindley_1-1" class="reference"><a href="#cite_note-Lindley-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-ATIS_9-0" class="reference"><a href="#cite_note-ATIS-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> Typically, once one party begins a transmission, the other party on the channel must wait for the transmission to complete, before replying.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> </p><p>An example of a half-duplex system is a two-party system such as a <a href="/wiki/Walkie-talkie" title="Walkie-talkie">walkie-talkie</a>, wherein one must say "over" or another previously designated keyword to indicate the end of transmission, to ensure that only one party transmits at a time. A good analogy for a half-duplex system would be a one-lane road that allows two-way traffic, traffic can only flow in one direction at a time. </p><p>Half-duplex systems are usually used to conserve <a href="/wiki/Bandwidth_(signal_processing)" title="Bandwidth (signal processing)">bandwidth</a>, at the cost of reducing the overall bidirectional throughput, since only a single <a href="/wiki/Communication_channel" title="Communication channel">communication channel</a> is needed and is shared alternately between the two directions. For example, a walkie-talkie or a DECT phone or so-called TDD 4G or 5G phones requires only a single <a href="/wiki/Frequency" title="Frequency">frequency</a> for bidirectional communication, while a <a href="/wiki/Cell_phone" class="mw-redirect" title="Cell phone">cell phone</a> in the so-called FDD mode is a full-duplex device, and generally requires two frequencies to carry the two simultaneous voice channels, one in each direction. </p><p>In automatic communications systems such as two-way data-links, <a href="/wiki/Time-division_multiplexing" title="Time-division multiplexing">time-division multiplexing</a> can be used for time allocations for communications in a half-duplex system. For example, station A on one end of the data link could be allowed to transmit for exactly one second, then station B on the other end could be allowed to transmit for exactly one second, and then the cycle repeats. In this scheme, the channel is never left idle. </p><p>In half-duplex systems, if more than one party transmits at the same time, a <a href="/wiki/Collision_(telecommunications)" title="Collision (telecommunications)">collision</a> occurs, resulting in lost or distorted messages. </p> <div class="mw-heading mw-heading2"><h2 id="Full_duplex"><span class="anchor" id="FULL-DUPLEX"></span><span class="anchor" id="Full-duplex"></span>Full duplex</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Duplex_(telecommunications)&action=edit&section=3" title="Edit section: Full duplex"><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:FullDuplex.JPG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/72/FullDuplex.JPG/220px-FullDuplex.JPG" decoding="async" width="220" height="63" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/72/FullDuplex.JPG/330px-FullDuplex.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/72/FullDuplex.JPG/440px-FullDuplex.JPG 2x" data-file-width="462" data-file-height="132" /></a><figcaption>A simple illustration of a full-duplex communication system. Full-duplex is not common in handheld radios as shown here due to the cost and complexity of common duplexing methods, but is used in <a href="/wiki/Telephone" title="Telephone">telephones</a>, <a href="/wiki/Cellphone" class="mw-redirect" title="Cellphone">cellphones</a> and <a href="/wiki/Cordless_phone" class="mw-redirect" title="Cordless phone">cordless phones</a>.</figcaption></figure> <p>A <b>full-duplex</b> (<b>FDX</b>) system allows communication in both directions, and, unlike half-duplex, allows this to happen simultaneously.<sup id="cite_ref-Sudakshina_6-1" class="reference"><a href="#cite_note-Sudakshina-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Frenzel_7-1" class="reference"><a href="#cite_note-Frenzel-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-ITU_8-1" class="reference"><a href="#cite_note-ITU-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> Land-line <a href="/wiki/Telephone" title="Telephone">telephone</a> networks are full-duplex since they allow both callers to speak and be heard at the same time. Full-duplex operation is achieved on a <a href="/wiki/Two-wire_circuit" title="Two-wire circuit">two-wire circuit</a> through the use of a <a href="/wiki/Hybrid_coil" class="mw-redirect" title="Hybrid coil">hybrid coil</a> in a <a href="/wiki/Telephone_hybrid" title="Telephone hybrid">telephone hybrid</a>. Modern cell phones are also full-duplex.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> </p><p>There is a technical distinction between full-duplex communication, which uses a single physical communication channel for both directions simultaneously, and <b>dual-simplex</b> communication which uses two distinct channels, one for each direction. From the user perspective, the technical difference does not matter and both variants are commonly referred to as <i>full duplex</i>. </p><p>Many <a href="/wiki/Ethernet" title="Ethernet">Ethernet</a> connections achieve full-duplex operation by making simultaneous use of two physical <a href="/wiki/Twisted_pair" title="Twisted pair">twisted pairs</a> inside the same jacket, or two optical fibers which are directly connected to each networked device: one pair or fiber is for receiving packets, while the other is for sending packets. Other Ethernet variants, such as <a href="/wiki/1000BASE-T" class="mw-redirect" title="1000BASE-T">1000BASE-T</a> use the same channels in each direction simultaneously. In any case, with full-duplex operation, the cable itself becomes a collision-free environment and doubles the maximum total transmission capacity supported by each Ethernet connection. </p><p>Full-duplex has also several benefits over the use of half-duplex. Since there is only one transmitter on each twisted pair there is no contention and no collisions so time is not wasted by having to wait or retransmit frames. Full transmission capacity is available in both directions because the send and receive functions are separate. </p><p>Some computer-based systems of the 1960s and 1970s required full-duplex facilities, even for half-duplex operation, since their poll-and-response schemes could not tolerate the slight delays in reversing the direction of transmission in a half-duplex line.<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 2021)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading3"><h3 id="Echo_cancellation">Echo cancellation</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Duplex_(telecommunications)&action=edit&section=4" title="Edit section: Echo cancellation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Full-duplex audio systems like telephones can create echo, which is distracting to users and impedes the performance of modems. Echo occurs when the sound originating from the far end comes out of the speaker at the near end and re-enters the microphone<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>a<span class="cite-bracket">]</span></a></sup> there and is then sent back to the far end. The sound then reappears at the original source end but delayed. </p><p><a href="/wiki/Echo_cancellation" class="mw-redirect" title="Echo cancellation">Echo cancellation</a> is a signal-processing operation that subtracts the far-end signal from the microphone signal before it is sent back over the network. Echo cancellation is important technology allowing <a href="/wiki/Modem" title="Modem">modems</a> to achieve good full-duplex performance. The <a href="/wiki/ITU-T_V.32" class="mw-redirect" title="ITU-T V.32">V.32</a>, <a href="/wiki/ITU-T_V.34" class="mw-redirect" title="ITU-T V.34">V.34</a>, <a href="/w/index.php?title=ITU-T_V.56&action=edit&redlink=1" class="new" title="ITU-T V.56 (page does not exist)">V.56</a>, and <a href="/wiki/ITU-T_V.90" class="mw-redirect" title="ITU-T V.90">V.90</a> modem standards require echo cancellation.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> Echo cancelers are available as both software and hardware implementations. They can be independent components in a communications system or integrated into the communication system's <a href="/wiki/Central_processing_unit" title="Central processing unit">central processing unit</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Full-duplex_emulation">Full-duplex emulation</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Duplex_(telecommunications)&action=edit&section=5" title="Edit section: Full-duplex emulation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Where <a href="/wiki/Channel_access_method" title="Channel access method">channel access methods</a> are used in <a href="/wiki/Point-to-multipoint" class="mw-redirect" title="Point-to-multipoint">point-to-multipoint</a> networks (such as <a href="/wiki/Cellular_network" title="Cellular network">cellular networks</a>) for dividing forward and reverse communication channels on the same physical communications medium, they are known as duplexing methods.<sup id="cite_ref-Gyasi-Agyei_14-0" class="reference"><a href="#cite_note-Gyasi-Agyei-14"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Time-division_duplexing">Time-division duplexing</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Duplex_(telecommunications)&action=edit&section=6" title="Edit section: Time-division duplexing"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><b>Time-division duplexing</b> (<b>TDD</b>) is the application of <a href="/wiki/Time-division_multiplexing" title="Time-division multiplexing">time-division multiplexing</a> to separate outward and return signals. It emulates full-duplex communication over a half-duplex communication link. </p><p>Time-division duplexing is flexible in the case where there is <a href="/wiki/Asymmetry" title="Asymmetry">asymmetry</a> of the <a href="/wiki/Telecommunications_link" title="Telecommunications link">uplink</a> and <a href="/wiki/Downlink" class="mw-redirect" title="Downlink">downlink</a> data rates or utilization. As the amount of uplink data increases, more communication capacity can be dynamically allocated, and as the traffic load becomes lighter, capacity can be taken away. The same applies in the downlink direction. </p><p>The <i>transmit/receive transition gap</i> (TTG) is the gap (time) between a downlink burst and the subsequent uplink burst. Similarly, the <i>receive/transmit transition gap</i> (RTG) is the gap between an uplink burst and the subsequent downlink burst.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> </p><p>Examples of time-division duplexing systems include: </p> <ul><li><a href="/wiki/UMTS-TDD" class="mw-redirect" title="UMTS-TDD">UMTS-TDD</a> for data communications on <a href="/wiki/3G" title="3G">3G</a> mobile networks</li> <li><a href="/wiki/LTE-TDD" class="mw-redirect" title="LTE-TDD">LTE-TDD</a> for data communications on <a href="/wiki/4G" title="4G">4G</a> mobile networks</li> <li><a href="/wiki/DECT" title="DECT">DECT</a> wireless telephony</li> <li>Half-duplex <a href="/wiki/Packet_switched" class="mw-redirect" title="Packet switched">packet switched</a> networks based on <a href="/wiki/Carrier-sense_multiple_access" title="Carrier-sense multiple access">carrier-sense multiple access</a>, for example 2-wire or <a href="/wiki/Ethernet_hub" title="Ethernet hub">hubbed Ethernet</a>, <a href="/wiki/Wireless_local_area_network" class="mw-redirect" title="Wireless local area network">Wireless local area networks</a> and <a href="/wiki/Bluetooth" title="Bluetooth">Bluetooth</a>, can be considered as time-division duplexing systems, albeit not TDMA with fixed frame-lengths.</li> <li><a href="/wiki/WiMAX" title="WiMAX">WiMAX</a></li> <li><a href="/wiki/PACTOR" title="PACTOR">PACTOR</a></li> <li>ISDN BRI <a href="/wiki/U_interface" title="U interface">U interface</a>, variants using the time-compression multiplex (TCM) line system</li> <li><a href="/wiki/G.fast" title="G.fast">G.fast</a>, a <a href="/wiki/Digital_subscriber_line" title="Digital subscriber line">digital subscriber line</a> (DSL) standard developed by the <a href="/wiki/ITU-T" title="ITU-T">ITU-T</a></li></ul> <div class="mw-heading mw-heading3"><h3 id="Frequency-division_duplexing">Frequency-division duplexing</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Duplex_(telecommunications)&action=edit&section=7" title="Edit section: Frequency-division duplexing"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></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">Not to be confused with <a href="/wiki/Frequency-division_multiplexing" title="Frequency-division multiplexing">Frequency-division multiplexing</a>.</div> <p><b>Frequency-division duplexing</b> (<b>FDD</b>) means that the <a href="/wiki/Transmitter" title="Transmitter">transmitter</a> and <a href="/wiki/Receiver_(radio)" class="mw-redirect" title="Receiver (radio)">receiver</a> operate using different <a href="/wiki/Carrier_frequencies" class="mw-redirect" title="Carrier frequencies">carrier frequencies</a>. </p><p>The method is frequently used in <a href="/wiki/Ham_radio" class="mw-redirect" title="Ham radio">ham radio</a> operation, where an operator is attempting to use a <a href="/wiki/Repeater" title="Repeater">repeater</a> station. The repeater station must be able to send and receive a transmission at the same time and does so by slightly altering the frequency at which it sends and receives. This mode of operation is referred to as <i>duplex mode</i> or <i>offset mode</i>. Uplink and downlink sub-bands are said to be separated by the <i>frequency offset</i>. </p><p>Frequency-division duplex systems can extend their range by using sets of simple repeater stations because the communications transmitted on any single frequency always travel in the same direction. </p><p>Frequency-division duplexing can be efficient in the case of symmetric traffic. In this case, time-division duplexing tends to waste bandwidth during the switch-over from transmitting to receiving, has greater inherent <a href="/wiki/Latency_(engineering)" title="Latency (engineering)">latency</a>, and may require more complex <a href="/wiki/Circuitry" class="mw-redirect" title="Circuitry">circuitry</a>. </p><p>Another advantage of frequency-division duplexing is that it makes radio planning easier and more efficient since base stations do not <i>hear</i> each other (as they transmit and receive in different sub-bands) and therefore will normally not interfere with each other. Conversely, with time-division duplexing systems, care must be taken to keep guard times between neighboring base stations (which decreases <a href="/wiki/Spectral_efficiency" title="Spectral efficiency">spectral efficiency</a>) or to synchronize base stations, so that they will transmit and receive at the same time (which increases network complexity and therefore cost, and reduces bandwidth allocation flexibility as all base stations and sectors will be forced to use the same uplink/downlink ratio). </p><p>Examples of frequency-division duplexing systems include: </p> <ul><li><a href="/wiki/ADSL" title="ADSL">ADSL</a> and <a href="/wiki/VDSL" title="VDSL">VDSL</a></li> <li><a href="/wiki/Mobile_technology" title="Mobile technology">Mobile technology</a>, including <a href="/wiki/Long_Term_Evolution" class="mw-redirect" title="Long Term Evolution">LTE</a>, <a href="/wiki/UMTS" title="UMTS">UMTS</a> and <a href="/wiki/CDMA2000" title="CDMA2000">CDMA2000</a></li> <li><a href="/wiki/IEEE_802.16" title="IEEE 802.16">IEEE 802.16</a> <a href="/wiki/WiMax" class="mw-redirect" title="WiMax">WiMax</a></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=Duplex_(telecommunications)&action=edit&section=8" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1184024115">.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}</style><div class="div-col" style="column-width: 20em;"> <ul><li><a href="/wiki/Communication_channel" title="Communication channel">Communication channel</a></li> <li><a href="/wiki/Crossband_operation" title="Crossband operation">Crossband operation</a></li> <li><a href="/wiki/Double-track_railway" title="Double-track railway">Double-track railway</a></li> <li><a href="/wiki/Duplex_mismatch" title="Duplex mismatch">Duplex mismatch</a></li> <li><a href="/wiki/Duplexer" title="Duplexer">Duplexer</a></li> <li><a href="/wiki/Four-wire_circuit" title="Four-wire circuit">Four-wire circuit</a></li> <li><a href="/wiki/Multiplexing" title="Multiplexing">Multiplexing</a></li> <li><a href="/wiki/Push-to-talk" title="Push-to-talk">Push-to-talk</a></li> <li><a href="/wiki/Radio_resource_management" title="Radio resource management">Radio resource management</a></li> <li><a href="/wiki/Simplex_communication" class="mw-redirect" title="Simplex communication">Simplex communication</a></li></ul> </div> <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=Duplex_(telecommunications)&action=edit&section=9" 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-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text">This feedback path may be acoustic, through the air, or it may be mechanically coupled, for example in a telephone handset.</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=Duplex_(telecommunications)&action=edit&section=10" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239543626"><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-Lindley-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-Lindley_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Lindley_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 id="CITEREFLindley2023" class="citation web cs1">Lindley, Matthew (12 February 2023). <a rel="nofollow" class="external text" href="https://www.wise-geek.com/what-is-a-two-way-radio.htm">"What is a Two-Way Radio?"</a>. <i>Technology</i>. WiseGeek website<span class="reference-accessdate">. Retrieved <span class="nowrap">27 February</span> 2023</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Technology&rft.atitle=What+is+a+Two-Way+Radio%3F&rft.date=2023-02-12&rft.aulast=Lindley&rft.aufirst=Matthew&rft_id=https%3A%2F%2Fwww.wise-geek.com%2Fwhat-is-a-two-way-radio.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADuplex+%28telecommunications%29" class="Z3988"></span></span> </li> <li id="cite_note-Gosling-2"><span class="mw-cite-backlink">^ <a href="#cite_ref-Gosling_2-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Gosling_2-1"><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="CITEREFGosling2000" class="citation book cs1">Gosling, William (2000). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=MvbZ2eK7luMC&q=simplex%20duplex"><i>Radio Spectrum Conservation</i></a>. Elsevier Science. pp. 170–171. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780750637404" title="Special:BookSources/9780750637404"><bdi>9780750637404</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Radio+Spectrum+Conservation&rft.pages=170-171&rft.pub=Elsevier+Science&rft.date=2000&rft.isbn=9780750637404&rft.aulast=Gosling&rft.aufirst=William&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DMvbZ2eK7luMC%26q%3Dsimplex%2520duplex&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADuplex+%28telecommunications%29" class="Z3988"></span></span> </li> <li id="cite_note-IEEE-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-IEEE_3-0">^</a></b></span> <span class="reference-text">"Simplex" <i>The IEEE Authoritative Dictionary of Standard Terms, 7th Ed.</i>, 2000, Inst. of Electrical and Electronic Engineers, p.1053</span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text">Milnor, J.W. and G.A. Randall. "The Newfoundland-Azores High-Speed Duplex Cable". <i>A.I.E.E. Electrical Engineering</i>. May 1931</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"><i>Report of the Committee on Public Emergency Service Communication</i>. NFPA 1221, May, 2002.</span> </li> <li id="cite_note-Sudakshina-6"><span class="mw-cite-backlink">^ <a href="#cite_ref-Sudakshina_6-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Sudakshina_6-1"><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="CITEREFSudakshina2010" class="citation book cs1">Sudakshina, Kundu (2010). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=JKfTrRRHT5QC&q=duplex%20simplex"><i>Analog and Digital Communications</i></a>. New Delhi: Dorling Kindersley. pp. 6–7. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9788131731871" title="Special:BookSources/9788131731871"><bdi>9788131731871</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Analog+and+Digital+Communications&rft.place=New+Delhi&rft.pages=6-7&rft.pub=Dorling+Kindersley&rft.date=2010&rft.isbn=9788131731871&rft.aulast=Sudakshina&rft.aufirst=Kundu&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DJKfTrRRHT5QC%26q%3Dduplex%2520simplex&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADuplex+%28telecommunications%29" class="Z3988"></span></span> </li> <li id="cite_note-Frenzel-7"><span class="mw-cite-backlink">^ <a href="#cite_ref-Frenzel_7-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Frenzel_7-1"><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="CITEREFFrenzel2017" class="citation book cs1">Frenzel, Louis (2017). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=uqjRDgAAQBAJ&dq=simplex+duplex&pg=PA161"><i>Electronics Explained: Fundamentals for Engineers, Technicians, and Makers, 2nd Ed</i></a>. Elsevier Science. p. 161. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780128118795" title="Special:BookSources/9780128118795"><bdi>9780128118795</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Electronics+Explained%3A+Fundamentals+for+Engineers%2C+Technicians%2C+and+Makers%2C+2nd+Ed.&rft.pages=161&rft.pub=Elsevier+Science&rft.date=2017&rft.isbn=9780128118795&rft.aulast=Frenzel&rft.aufirst=Louis&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DuqjRDgAAQBAJ%26dq%3Dsimplex%2Bduplex%26pg%3DPA161&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADuplex+%28telecommunications%29" class="Z3988"></span></span> </li> <li id="cite_note-ITU-8"><span class="mw-cite-backlink">^ <a href="#cite_ref-ITU_8-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-ITU_8-1"><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 class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.itu.int/br_tsb_terms/#/?q=duplex&sector=T,R&from=2005-01-01&to=2023-02-27&status=1&type=any&page=1">"Duplex"</a>. <i>Terms and Definitions Database</i>. International Telecommunications Union (ITU) website<span class="reference-accessdate">. Retrieved <span class="nowrap">27 February</span> 2023</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Terms+and+Definitions+Database&rft.atitle=Duplex&rft_id=https%3A%2F%2Fwww.itu.int%2Fbr_tsb_terms%2F%23%2F%3Fq%3Dduplex%26sector%3DT%2CR%26from%3D2005-01-01%26to%3D2023-02-27%26status%3D1%26type%3Dany%26page%3D1&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADuplex+%28telecommunications%29" class="Z3988"></span></span> </li> <li id="cite_note-ATIS-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-ATIS_9-0">^</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://glossary.atis.org/search-results/?search=duplex">"Half-duplex"</a>. <i>ATIS Telecom Glossary</i>. Alliance for Telecommunications Industry Solutions<span class="reference-accessdate">. Retrieved <span class="nowrap">27 February</span> 2023</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=ATIS+Telecom+Glossary&rft.atitle=Half-duplex&rft_id=https%3A%2F%2Fglossary.atis.org%2Fsearch-results%2F%3Fsearch%3Dduplex&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADuplex+%28telecommunications%29" class="Z3988"></span> This definition is accredited by the American National Standards Institute (ANSI)</span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</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.pcmag.com/encyclopedia/term/half-duplex">"half-duplex"</a>. <i>www.pcmag.com</i><span class="reference-accessdate">. Retrieved <span class="nowrap">20 June</span> 2023</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.pcmag.com&rft.atitle=half-duplex&rft_id=https%3A%2F%2Fwww.pcmag.com%2Fencyclopedia%2Fterm%2Fhalf-duplex&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADuplex+%28telecommunications%29" class="Z3988"></span></span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</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="http://electronics.howstuffworks.com/cell-phone1.htm">"Cell phone Frequencies"</a>. <i>HowStuffWorks</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2019-02-14</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=HowStuffWorks&rft.atitle=Cell+phone+Frequencies&rft_id=http%3A%2F%2Felectronics.howstuffworks.com%2Fcell-phone1.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADuplex+%28telecommunications%29" class="Z3988"></span></span> </li> <li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGreensteinStango2006" class="citation book cs1">Greenstein, Shane; Stango, Victor (2006). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=3hMKHwUmaZ8C&pg=PA129"><i>Standards and Public Policy</i></a>. Cambridge University Press. pp. 129–132. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-139-46075-0" title="Special:BookSources/978-1-139-46075-0"><bdi>978-1-139-46075-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Standards+and+Public+Policy&rft.pages=129-132&rft.pub=Cambridge+University+Press&rft.date=2006&rft.isbn=978-1-139-46075-0&rft.aulast=Greenstein&rft.aufirst=Shane&rft.au=Stango%2C+Victor&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D3hMKHwUmaZ8C%26pg%3DPA129&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADuplex+%28telecommunications%29" class="Z3988"></span></span> </li> <li id="cite_note-Gyasi-Agyei-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-Gyasi-Agyei_14-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGyasi-Agyei2019" class="citation book cs1">Gyasi-Agyei, Amoakoh (2019). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=dmmhDwAAQBAJ&dq=communications+engineering+simplex+duplex&pg=PA519"><i>Telecommunications Engineering: Principles And Practice</i></a>. World Scientific Publishing Company. pp. 519–520. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9789811200274" title="Special:BookSources/9789811200274"><bdi>9789811200274</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Telecommunications+Engineering%3A+Principles+And+Practice&rft.pages=519-520&rft.pub=World+Scientific+Publishing+Company&rft.date=2019&rft.isbn=9789811200274&rft.aulast=Gyasi-Agyei&rft.aufirst=Amoakoh&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DdmmhDwAAQBAJ%26dq%3Dcommunications%2Bengineering%2Bsimplex%2Bduplex%26pg%3DPA519&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADuplex+%28telecommunications%29" class="Z3988"></span></span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</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="http://www.rfwireless-world.com/Terminology/TTG-gap-vs-RTG-gap-in-WiMAX-LTE.html">"TTG vs RTG-What is TTG and RTG Gaps in WIMAX, LTE"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">2021-06-05</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=TTG+vs+RTG-What+is+TTG+and+RTG+Gaps+in+WIMAX%2C+LTE&rft_id=http%3A%2F%2Fwww.rfwireless-world.com%2FTerminology%2FTTG-gap-vs-RTG-gap-in-WiMAX-LTE.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADuplex+%28telecommunications%29" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Duplex_(telecommunications)&action=edit&section=11" title="Edit section: Further reading"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTanenbaum2003" class="citation book cs1"><a href="/wiki/Andrew_S._Tanenbaum" title="Andrew S. Tanenbaum">Tanenbaum, Andrew S.</a> (2003). <span class="id-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://archive.org/details/computernetworks00tane_2"><i>Computer Networks</i></a></span>. Prentice Hall. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-13-038488-7" title="Special:BookSources/0-13-038488-7"><bdi>0-13-038488-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Computer+Networks&rft.pub=Prentice+Hall&rft.date=2003&rft.isbn=0-13-038488-7&rft.aulast=Tanenbaum&rft.aufirst=Andrew+S.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fcomputernetworks00tane_2&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADuplex+%28telecommunications%29" class="Z3988"></span></li></ul> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRiihonen2014" class="citation book cs1">Riihonen, Taneli (2014). <a rel="nofollow" class="external text" href="http://theses.eurasip.org/theses/637/design-and-analysis-of-duplexing-modes-and/download/"><i>Design and Analysis of Duplexing Modes and Forwarding Protocols for OFDM(A) Relay Links</i></a>. Aalto University publication series DOCTORAL DISSERTATIONS, 81/2014. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-952-60-5715-6" title="Special:BookSources/978-952-60-5715-6"><bdi>978-952-60-5715-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Design+and+Analysis+of+Duplexing+Modes+and+Forwarding+Protocols+for+OFDM%28A%29+Relay+Links&rft.pub=Aalto+University+publication+series+DOCTORAL+DISSERTATIONS%2C+81%2F2014&rft.date=2014&rft.isbn=978-952-60-5715-6&rft.aulast=Riihonen&rft.aufirst=Taneli&rft_id=http%3A%2F%2Ftheses.eurasip.org%2Ftheses%2F637%2Fdesign-and-analysis-of-duplexing-modes-and%2Fdownload%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ADuplex+%28telecommunications%29" class="Z3988"></span></li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist 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control</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Circuit_switching" title="Circuit switching">Channel-based</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Frequency-division_multiple_access" title="Frequency-division multiple access">FDMA</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/Frequency-division_multiplexing" title="Frequency-division multiplexing">FDM</a> <ul><li><a href="/wiki/Orthogonal_frequency-division_multiple_access" title="Orthogonal frequency-division multiple access">OFDMA</a></li> <li><a href="/wiki/Single-carrier_FDMA" title="Single-carrier FDMA">SC-FDMA</a></li></ul></li> <li><a href="/wiki/Wavelength-division_multiplexing" title="Wavelength-division multiplexing">WDM</a> <ul><li><a href="/wiki/Wavelength-division_multiple_access" class="mw-redirect" title="Wavelength-division multiple access">WDMA</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Time-division_multiple_access" title="Time-division multiple access">TDMA</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/Multi-frequency_time-division_multiple_access" title="Multi-frequency time-division multiple access">MF-TDMA</a></li> <li><a href="/wiki/Self-organized_time-division_multiple_access" title="Self-organized time-division multiple access">STDMA</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Code-division_multiple_access" title="Code-division multiple access">CDMA</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/W-CDMA" class="mw-redirect" title="W-CDMA">W-CDMA</a></li> <li><a href="/wiki/TD-CDMA" class="mw-redirect" title="TD-CDMA">TD-CDMA</a></li> <li><a href="/wiki/TD-SCDMA" class="mw-redirect" title="TD-SCDMA">TD-SCDMA</a></li> <li><a href="/wiki/Direct-sequence_spread_spectrum" title="Direct-sequence spread spectrum">DS-CDMA</a></li> <li><a href="/wiki/Frequency-hopping_spread_spectrum" title="Frequency-hopping spread spectrum">FH-CDMA</a></li> <li><a href="/wiki/Multi-carrier_code-division_multiple_access" title="Multi-carrier code-division multiple access">MC-CDMA</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Space-division_multiple_access" title="Space-division multiple access">SDMA</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/IBurst" class="mw-redirect" title="IBurst">HC-SDMA</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Polarization-division_multiple_access" title="Polarization-division multiple access">PDMA</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 class="mw-empty-elt"></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Pulse-address_multiple_access" title="Pulse-address multiple access">PAMA</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 class="mw-empty-elt"></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Packet_switching" title="Packet switching">Packet-based</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Contention_(telecommunications)" title="Contention (telecommunications)">Collision recovery</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/ALOHAnet#The_ALOHA_protocol" title="ALOHAnet">ALOHA</a></li> <li><a href="/wiki/ALOHAnet" title="ALOHAnet">Slotted ALOHA</a></li> <li><a href="/wiki/Reservation_ALOHA" class="mw-redirect" title="Reservation ALOHA">R-ALOHA</a></li> <li><a href="/wiki/AX.25" title="AX.25">AX.25</a></li> <li><a href="/wiki/Carrier-sense_multiple_access_with_collision_detection" title="Carrier-sense multiple access with collision detection">CSMA/CD</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Contention_(telecommunications)" title="Contention (telecommunications)">Collision avoidance</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/Multiple_Access_with_Collision_Avoidance" class="mw-redirect" title="Multiple Access with Collision Avoidance">MACA</a></li> <li><a href="/wiki/Multiple_Access_with_Collision_Avoidance_for_Wireless" title="Multiple Access with Collision Avoidance for Wireless">MACAW</a></li> <li><a href="/wiki/Carrier-sense_multiple_access" title="Carrier-sense multiple access">CSMA</a></li> <li><a href="/wiki/Carrier-sense_multiple_access_with_collision_avoidance" title="Carrier-sense multiple access with collision avoidance">CSMA/CA</a></li> <li><a href="/wiki/Distributed_coordination_function" title="Distributed coordination function">DCF</a></li> <li><a href="/wiki/Point_coordination_function" title="Point coordination function">PCF</a></li> <li><a href="/wiki/IEEE_802.11e-2005#802.11e_MAC_protocol_operation" title="IEEE 802.11e-2005">HCF</a></li> <li><a href="/wiki/CSMA/CARP" class="mw-redirect" title="CSMA/CARP">CSMA/CARP</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Collision_domain" title="Collision domain">Collision-free</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/Token_Ring" title="Token Ring">Token Ring</a></li> <li><a href="/wiki/Token_bus_network" title="Token bus network">Token bus</a></li> <li><a href="/wiki/Mobile_Slotted_Aloha" title="Mobile Slotted Aloha">MS-ALOHA</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Delay and disruption tolerant</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/Mobile_ad_hoc_network" class="mw-redirect" title="Mobile ad hoc network">MANET</a></li> <li><a href="/wiki/Vehicular_ad-hoc_network" class="mw-redirect" title="Vehicular ad-hoc network">VANET</a></li> <li><a href="/wiki/Delay-tolerant_networking" title="Delay-tolerant networking">DTN</a></li> <li><a href="/wiki/Dynamic_Source_Routing" title="Dynamic Source Routing">Dynamic Source Routing</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a class="mw-selflink selflink">Duplexing methods</a></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 class="mw-selflink-fragment" href="#Time-division_duplexing">TDD</a></li> <li><a class="mw-selflink-fragment" href="#Frequency-division_duplexing">FDD</a></li></ul> </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" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/24px-Telecom-icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/32px-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></li> <li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Telecommunications" title="Category:Telecommunications">Category</a></li> <li><span class="noviewer" typeof="mw:File"><span title="List-Class article"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/16px-Symbol_list_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/23px-Symbol_list_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/31px-Symbol_list_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Outline_of_telecommunication" title="Outline of telecommunication">Outline</a></li> <li><span class="noviewer" typeof="mw:File"><span title="Commons page"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/12px-Commons-logo.svg.png" decoding="async" width="12" height="16" class="mw-file-element" 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