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class="vector-toc-link" href="#Optical_communications"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Optical communications</span> </div> </a> <ul id="toc-Optical_communications-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Aviation" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Aviation"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Aviation</span> </div> </a> <button aria-controls="toc-Aviation-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 Aviation subsection</span> </button> <ul id="toc-Aviation-sublist" class="vector-toc-list"> <li id="toc-Marine" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Marine"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Marine</span> </div> </a> <ul id="toc-Marine-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Other_applications" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Other_applications"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Other applications</span> </div> </a> <button aria-controls="toc-Other_applications-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 Other applications subsection</span> </button> <ul id="toc-Other_applications-sublist" class="vector-toc-list"> <li id="toc-Electronic_toll_collection" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Electronic_toll_collection"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Electronic toll collection</span> </div> </a> <ul id="toc-Electronic_toll_collection-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Lap_timing" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Lap_timing"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>Lap timing</span> </div> </a> <ul id="toc-Lap_timing-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Car_keys" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Car_keys"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.3</span> <span>Car keys</span> </div> </a> <ul id="toc-Car_keys-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Gated_communities" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Gated_communities"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.4</span> <span>Gated communities</span> </div> </a> <ul id="toc-Gated_communities-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-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">6</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading">Transponder: Difference between revisions</h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet 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/%D9%85%D8%B9%D9%8A%D8%AF_%D8%A8%D8%AB" title="معيد بث – Arabic" lang="ar" hreflang="ar" data-title="معيد بث" 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/Transponedor" title="Transponedor – Catalan" lang="ca" hreflang="ca" data-title="Transponedor" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Transponder" title="Transponder – Danish" lang="da" hreflang="da" data-title="Transponder" 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/Transponder" title="Transponder – German" lang="de" hreflang="de" data-title="Transponder" 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/Transponder" title="Transponder – Estonian" lang="et" hreflang="et" data-title="Transponder" 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/Transpondedor" title="Transpondedor – Spanish" lang="es" hreflang="es" data-title="Transpondedor" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%AA%D8%B1%D8%A7%D9%86%D8%B3%D9%BE%D9%88%D9%86%D8%AF%D8%B1" title="ترانسپوندر – Persian" lang="fa" hreflang="fa" data-title="ترانسپوندر" 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/Transpondeur" title="Transpondeur – French" lang="fr" hreflang="fr" data-title="Transpondeur" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/Trasfhreagr%C3%B3ir" title="Trasfhreagróir – Irish" lang="ga" hreflang="ga" data-title="Trasfhreagróir" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%ED%8A%B8%EB%9E%9C%EC%8A%A4%ED%8F%B0%EB%8D%94" title="트랜스폰더 – Korean" lang="ko" hreflang="ko" data-title="트랜스폰더" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%9F%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%82%E0%A4%B8%E0%A4%AA%E0%A5%8B%E0%A4%82%E0%A4%A1%E0%A4%B0" title="ट्रांसपोंडर – Hindi" lang="hi" hreflang="hi" data-title="ट्रांसपोंडर" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-io mw-list-item"><a href="https://io.wikipedia.org/wiki/Transmis-respondilo" title="Transmis-respondilo – Ido" lang="io" hreflang="io" data-title="Transmis-respondilo" data-language-autonym="Ido" data-language-local-name="Ido" class="interlanguage-link-target"><span>Ido</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Pemanggap" title="Pemanggap – Indonesian" lang="id" hreflang="id" data-title="Pemanggap" 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/Transponder" title="Transponder – Italian" lang="it" hreflang="it" data-title="Transponder" 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%9E%D7%A9%D7%99%D7%91_(RF)" title="משיב (RF) – Hebrew" lang="he" hreflang="he" data-title="משיב (RF)" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-jv mw-list-item"><a href="https://jv.wikipedia.org/wiki/Transponder" title="Transponder – Javanese" lang="jv" hreflang="jv" data-title="Transponder" data-language-autonym="Jawa" data-language-local-name="Javanese" class="interlanguage-link-target"><span>Jawa</span></a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%9F%E0%B5%8D%E0%B4%B0%E0%B4%BE%E0%B5%BB%E0%B4%B8%E0%B5%8D%E0%B4%AA%E0%B5%8B%E0%B4%A3%E0%B5%8D%E0%B4%9F%E0%B5%BC" title="ട്രാൻസ്പോണ്ടർ – Malayalam" lang="ml" hreflang="ml" data-title="ട്രാൻസ്പോണ്ടർ" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target"><span>മലയാളം</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Transponder" title="Transponder – Malay" lang="ms" hreflang="ms" data-title="Transponder" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Transponder" title="Transponder – Dutch" lang="nl" hreflang="nl" data-title="Transponder" 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/%E3%83%88%E3%83%A9%E3%83%B3%E3%82%B9%E3%83%9D%E3%83%B3%E3%83%80" title="トランスポンダ – Japanese" lang="ja" hreflang="ja" data-title="トランスポンダ" 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/Transponder" title="Transponder – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Transponder" 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-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Transponder" title="Transponder – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Transponder" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Transponder" title="Transponder – Polish" lang="pl" hreflang="pl" data-title="Transponder" 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/Transponder" title="Transponder – Portuguese" lang="pt" hreflang="pt" data-title="Transponder" 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%A2%D1%80%D0%B0%D0%BD%D1%81%D0%BF%D0%BE%D0%BD%D0%B4%D0%B5%D1%80" title="Транспондер – Russian" lang="ru" hreflang="ru" data-title="Транспондер" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Toisiotutka#Toisiotutkavastain" title="Toisiotutka – Finnish" lang="fi" hreflang="fi" data-title="Toisiotutka" 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/Transponder" title="Transponder – Swedish" lang="sv" hreflang="sv" data-title="Transponder" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Transponder" title="Transponder – Turkish" lang="tr" hreflang="tr" data-title="Transponder" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%A2%D1%80%D0%B0%D0%BD%D1%81%D0%BF%D0%BE%D0%BD%D0%B4%D0%B5%D1%80" title="Транспондер – Ukrainian" lang="uk" hreflang="uk" data-title="Транспондер" 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/B%E1%BB%99_ph%C3%A1t_%C4%91%C3%A1p" title="Bộ phát đáp – Vietnamese" lang="vi" hreflang="vi" data-title="Bộ phát đáp" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a 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It allows adding a reason in the summary.">undo</a></span></strong></div><div id="mw-diff-ntitle2"><a href="/wiki/User:G%C3%BCnniX" class="mw-userlink" title="User:GünniX" data-mw-revid="1251632918"><bdi>GünniX</bdi></a> <span class="mw-usertoollinks">(<a href="/wiki/User_talk:G%C3%BCnniX" class="mw-usertoollinks-talk" title="User talk:GünniX">talk</a> | <a href="/wiki/Special:Contributions/G%C3%BCnniX" class="mw-usertoollinks-contribs" title="Special:Contributions/GünniX">contribs</a>)</span><div class="mw-diff-usermetadata"><div class="mw-diff-userroles"><a href="/wiki/Wikipedia:Extended_confirmed_editors" class="mw-redirect" title="Wikipedia:Extended confirmed editors">Extended confirmed users</a></div><div class="mw-diff-usereditcount"><span>309,132</span> edits</div></div></div><div id="mw-diff-ntitle3"><abbr class="minoredit" title="This is a minor edit">m</abbr> <span class="comment comment--without-parentheses">v2.05 - Fix errors for <a href="/wiki/Wikipedia:WCW" class="mw-redirect" title="Wikipedia:WCW">CW project</a> (Template without correct beginning - URL without http://)</span></div><div id="mw-diff-ntitle5"><span class="mw-tag-markers"><a href="/wiki/Special:Tags" title="Special:Tags">Tag</a>: <span class="mw-tag-marker mw-tag-marker-WPCleaner"><a href="/wiki/Wikipedia:WPCleaner" title="Wikipedia:WPCleaner">WPCleaner</a></span></span></div><div id="mw-diff-ntitle4"> </div></td> </tr><tr><td colspan="4" class="diff-multi" lang="en">(11 intermediate revisions by 9 users not shown)</td></tr><tr> <td colspan="2" class="diff-lineno">Line 2:</td> <td colspan="2" class="diff-lineno">Line 2:</td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>[[Image:407 Transponder.jpg|thumb|right|120px|A [[Ontario Highway 407|Highway 407]] toll transponder]]</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>[[Image:407 Transponder.jpg|thumb|right|120px|A [[Ontario Highway 407|Highway 407]] toll transponder]]</div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>In [[telecommunications]], a '''transponder''' is a device that, upon receiving a signal, emits a different signal in response.<ref>{{Cite web|url=https://www.merriam-webster.com/dictionary/transponder|title=Definition of TRANSPONDER}}</ref> The term is a [[blend word|blend]] of ''transmitter'' and ''responder''.<ref>[http://dictionary.reference.com/browse/transponder transponder]</ref> </div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>In [[telecommunications]], a '''transponder''' is a device that, upon receiving a signal, emits a different signal in response.<ref>{{Cite web|url=https://www.merriam-webster.com/dictionary/transponder|title=Definition of TRANSPONDER<ins class="diffchange diffchange-inline">|date=22 July 2023 </ins>}}</ref> The term is a [[blend word|blend]] of ''transmitter'' and ''responder''.<ref>[http://dictionary.reference.com/browse/transponder transponder]</ref><ins class="diffchange diffchange-inline"><ref>{{cite</ins> <ins class="diffchange diffchange-inline">news |title=Kunkune |url=https://kunkune.co.uk/ |publisher=Tech Accessories}}</ref></ins></div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>In [[air navigation]] or [[radio frequency identification]], a [[Transponder (aeronautics)|flight transponder]] is an automated [[transceiver]] in an aircraft that emits a coded identifying signal in response to an interrogating received signal. In a [[communications satellite]], a [[Transponder (satellite communications)|satellite transponder]] receives signals over a range of uplink frequencies, usually from a [[satellite ground station]]; the transponder amplifies them, and re-transmits them on a different set of downlink frequencies to receivers on Earth, often without changing the content of the received signal or signals.</div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>In [[air navigation]] or [[radio frequency identification]], a [[Transponder (aeronautics)|flight transponder]] is an automated [[transceiver]] in an aircraft that emits a coded identifying signal in response to an interrogating received signal. </div></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div></div></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>In a [[communications satellite]], a [[Transponder (satellite communications)|satellite transponder]] receives signals over a range of uplink frequencies, usually from a [[satellite ground station]]; the transponder amplifies them, and re-transmits them on a different set of downlink frequencies to receivers on Earth, often without changing the content of the received signal or signals.</div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>==Satellite/broadcast communications==</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>==Satellite/broadcast communications==</div></td> </tr> <tr> <td colspan="2" class="diff-lineno">Line 10:</td> <td colspan="2" class="diff-lineno">Line 12:</td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>A [[communications satellite]]’s [[Communication channel|channels]] are called transponders because each is a separate [[transceiver]] or [[repeater]]. With [[digital video]] [[data compression]] and [[multiplexing]], several [[video]] and [[sound reproduction|audio]] channels may travel through a single transponder on a single [[wideband]] [[carrier signal|carrier]]. Original [[analog video]] only has one channel per transponder, with [[subcarrier]]s for audio and automatic transmission identification service ([[Automatic Transmitter Identification System (television)|ATIS]]). Non-multiplexed [[radio station]]s can also travel in [[single channel per carrier]] (SCPC) mode, with multiple carriers (analog or digital) per transponder. This allows each station to transmit directly to the satellite, rather than paying for a whole transponder, or using [[landline]]s to send it to an [[Earth station (communications)|earth station]] for multiplexing with other stations.</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>A [[communications satellite]]’s [[Communication channel|channels]] are called transponders because each is a separate [[transceiver]] or [[repeater]]. With [[digital video]] [[data compression]] and [[multiplexing]], several [[video]] and [[sound reproduction|audio]] channels may travel through a single transponder on a single [[wideband]] [[carrier signal|carrier]]. Original [[analog video]] only has one channel per transponder, with [[subcarrier]]s for audio and automatic transmission identification service ([[Automatic Transmitter Identification System (television)|ATIS]]). Non-multiplexed [[radio station]]s can also travel in [[single channel per carrier]] (SCPC) mode, with multiple carriers (analog or digital) per transponder. This allows each station to transmit directly to the satellite, rather than paying for a whole transponder, or using [[landline]]s to send it to an [[Earth station (communications)|earth station]] for multiplexing with other stations.</div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>==<del class="diffchange diffchange-inline"> </del>Optical communications<del class="diffchange diffchange-inline"> </del>==</div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>==Optical communications==</div></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>In [[<del class="diffchange diffchange-inline">optical </del>fiber <del class="diffchange diffchange-inline">communications</del>]], a transponder is the element that sends and receives the optical signal from a [[<del class="diffchange diffchange-inline">Optical</del> fiber|fiber]]. A transponder is typically characterized by its data rate and the maximum distance the signal can travel.</div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>In [[fiber<ins class="diffchange diffchange-inline">-optic</ins> <ins class="diffchange diffchange-inline">communication</ins>]]<ins class="diffchange diffchange-inline">s</ins>, a transponder is the element that sends and receives the optical signal from a [[<ins class="diffchange diffchange-inline">optical</ins> fiber|fiber]]. A transponder is typically characterized by its data rate and the maximum distance the signal can travel.</div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>The term "transponder" can apply to different items with important functional differences, mentioned across academic and commercial literature:</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>The term "transponder" can apply to different items with important functional differences, mentioned across academic and commercial literature:</div></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>* according to one description,<ref>[https://books.google.com/books?id=xTIonQZI7TMC&<del class="diffchange diffchange-inline">lpg=PA349&dq</del>=%<del class="diffchange diffchange-inline">22optical%20fiber%20telecommunications%20V</del>%22<del class="diffchange diffchange-inline">%20transceiver</del>&pg=PA353<del class="diffchange diffchange-inline">#v=onepage&q=%22MSA%20transceivers%20and%20MSA%20transponders%22&f=false</del> Optical Fiber Telecommunications V: Systems and networks, Academic Press, 2008, page 353-354]</ref> a transponder and [[transceiver]] are both functionally similar devices that convert a [[full-duplex]] ''electrical'' signal into a full-duplex optical signal. The difference between the two is that transceivers interface electrically with the host system using a ''serial'' interface, whereas transponders use a ''parallel'' interface to do so. In this view, transponders provide easier-to-handle lower-rate parallel signals, but are bulkier and consume more power than transceivers.</div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>* according to one description,<ref>[https://books.google.com/books?id=xTIonQZI7TMC&<ins class="diffchange diffchange-inline">q</ins>=%<ins class="diffchange diffchange-inline">22MSA+transceivers+and+MSA+transponders</ins>%22&pg=PA353 Optical Fiber Telecommunications V: Systems and networks, Academic Press, 2008, page 353-354]</ref> a transponder and [[transceiver]] are both functionally similar devices that convert a [[full-duplex]] ''electrical'' signal into a full-duplex optical signal. The difference between the two is that transceivers interface electrically with the host system using a ''serial'' interface, whereas transponders use a ''parallel'' interface to do so. In this view, transponders provide easier-to-handle lower-rate parallel signals, but are bulkier and consume more power than transceivers.</div></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>* according to another description,<ref><del class="diffchange diffchange-inline">[</del>http://www.compeng.dit.ie/staff/tfreir/optical_2/Unit_4.ppt WDM and DWDM Multiplexing Powerpoint presentation, School of Electronic and Communications Engineering, Dublin (Ireland), slide 61<del class="diffchange diffchange-inline">]</del></ref> transceivers are limited to providing an ''electrical-optical'' function only (not differentiating between serial or parallel electrical interfaces), whereas transponders convert an optical signal at one [[wavelength]] to an optical signal at another wavelength (typically [[Frequency grid|ITU standardized]] for [[DWDM]] communication). As such, transponders can be considered as two transceivers placed back-to-back. This view also seems to be held by <del class="diffchange diffchange-inline">e.g.</del> [[Fujitsu]].<ref>[http://www.fujitsu.com/downloads/TEL/fnc/pdfservices/DWDM_Tutorial.pdf Fujitsu DWDM Primer, 2004]</ref></div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>* according to another description,<ref><ins class="diffchange diffchange-inline">{{Cite web |url=</ins>http://www.compeng.dit.ie/staff/tfreir/optical_2/Unit_4.ppt <ins class="diffchange diffchange-inline">|title=</ins>WDM and DWDM Multiplexing Powerpoint presentation, School of Electronic and Communications Engineering, Dublin (Ireland), slide 61<ins class="diffchange diffchange-inline"> |access-date=2011-02-16 |archive-date=2011-07-21 |archive-url=https://web.archive.org/web/20110721123432/http://www.compeng.dit.ie/staff/tfreir/optical_2/Unit_4.ppt |url-status=dead }}</ins></ref> transceivers are limited to providing an ''electrical-optical'' function only (not differentiating between serial or parallel electrical interfaces), whereas transponders convert an optical signal at one [[wavelength]] to an optical signal at another wavelength (typically [[Frequency grid|ITU standardized]] for [[DWDM]] communication). As such, transponders can be considered as two transceivers placed back-to-back. This view also seems to be held by<ins class="diffchange diffchange-inline">,</ins> <ins class="diffchange diffchange-inline">for example,</ins> [[Fujitsu]].<ref>[http://www.fujitsu.com/downloads/TEL/fnc/pdfservices/DWDM_Tutorial.pdf Fujitsu DWDM Primer, 2004]</ref></div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>As a result, <del class="diffchange diffchange-inline">difference</del> in transponder functionality also might influence the functional description of related optical modules like <del class="diffchange diffchange-inline">[[</del>transceivers<del class="diffchange diffchange-inline">]]</del> and [[muxponder]]s.</div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>As a result, <ins class="diffchange diffchange-inline">differences</ins> in transponder functionality also might influence the functional description of related optical modules like transceivers and [[muxponder]]s.</div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>==Aviation==</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>==Aviation==</div></td> </tr> <tr> <td colspan="2" class="diff-lineno">Line 24:</td> <td colspan="2" class="diff-lineno">Line 26:</td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>[[File:Transponder in Private Aircraft.jpg|thumb|A transponder in a private plane squawking 2000]]</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>[[File:Transponder in Private Aircraft.jpg|thumb|A transponder in a private plane squawking 2000]]</div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>Another type of transponder occurs in [[identification friend or foe]] (IFF) systems in [[military aviation]] and in [[air traffic control]] [[secondary surveillance radar]] (beacon radar) systems for [[general aviation]] and [[commercial aviation]].<ref>{{cite journal |last1=Dobkin |first1=Daniel M. |title=A Radio-Oriented Introduction to Radio Frequency Identification |journal=High Frequency Electronics |date=2005}}</ref> <del class="diffchange diffchange-inline">[[Radar|Primary radar]] works best with large all-metal aircraft, but not so well on small, composite aircraft. Its range is also limited by terrain and rain or snow and also detects unwanted objects such as automobiles, hills and trees. Furthermore, it cannot always estimate the altitude of an aircraft. [[Secondary radar]] overcomes these limitations but it depends on a transponder in the aircraft to respond to interrogations from the ground station to make the plane more visible.</del></div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>Another type of transponder occurs in [[identification friend or foe]] (IFF) systems in [[military aviation]] and in [[air traffic control]] [[secondary surveillance radar]] (beacon radar) systems for [[general aviation]] and [[commercial aviation]].<ref>{{cite journal |last1=Dobkin |first1=Daniel M. |title=A Radio-Oriented Introduction to Radio Frequency Identification |journal=High Frequency Electronics |date=2005}}</ref> </div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>[[Radar|Primary radar]] works best with large all-metal aircraft, but not so well on small, composite aircraft. Its range is also limited by terrain and rain or snow and also detects unwanted objects such as automobiles, hills and trees. Furthermore, it cannot always estimate the altitude of an aircraft. [[Secondary radar]] overcomes these limitations but it depends on a transponder in the aircraft to respond to interrogations from the ground station to make the plane more visible.{{cn|date=May 2024}}</div></td> </tr> <tr> <td class="diff-marker"><a class="mw-diff-movedpara-left" title="Paragraph was moved. Click to jump to new location." href="#movedpara_16_0_rhs">⚫</a></td> <td class="diff-deletedline diff-side-deleted"><div><a name="movedpara_14_0_lhs"></a>Depending on the type of interrogation, the transponder sends back a [[transponder code]] (or "squawk code", Mode A) or altitude information (Mode C) to help air traffic controllers to identify the aircraft and to maintain separation between planes. Another mode called Mode S (Mode Select) is designed to help avoiding over-interrogation of the transponder (having many radars in busy areas) and to allow automatic collision avoidance. Mode S transponders are [[backward compatible]] with Modes A and C. Mode S is mandatory in [[controlled airspace]] in many countries. Some countries have also required, or are moving toward requiring, that all aircraft be equipped with Mode S, even in [[uncontrolled airspace]]. However, in the field of general aviation there have been objections to these moves, because of the cost, size, limited benefit to the users in uncontrolled airspace, and, in the case of [[balloon (aeronautics)|balloons]] and [[Glider (sailplane)|gliders]], the power requirements during long flights.</div></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker"><a class="mw-diff-movedpara-right" title="Paragraph was moved. Click to jump to old location." href="#movedpara_14_0_lhs">⚫</a></td> <td class="diff-addedline diff-side-added"><div><a name="movedpara_16_0_rhs"></a>Depending on the type of interrogation, the transponder sends back a [[transponder code]] (or "squawk code", Mode A) or altitude information (Mode C) to help air traffic controllers to identify the aircraft and to maintain separation between planes. Another mode called Mode S (Mode Select) is designed to help avoiding over-interrogation of the transponder (having many radars in busy areas) and to allow automatic collision avoidance. Mode S transponders are [[backward compatible]] with Modes A and C. Mode S is mandatory in [[controlled airspace]] in many countries. Some countries have also required, or are moving toward requiring, that all aircraft be equipped with Mode S, even in [[uncontrolled airspace]]. However, in the field of general aviation there have been objections to these moves, because of the cost, size, limited benefit to the users in uncontrolled airspace, and, in the case of [[balloon (aeronautics)|balloons]] and [[Glider (sailplane)|gliders]], the power requirements during long flights.<ins class="diffchange diffchange-inline">{{cn|date=May 2024}}</ins></div></td> </tr> <tr> <td class="diff-marker"><a class="mw-diff-movedpara-left" title="Paragraph was moved. Click to jump to new location." href="#movedpara_19_0_rhs">⚫</a></td> <td class="diff-deletedline diff-side-deleted"><div><a name="movedpara_17_0_lhs"></a>Transponders are used on some military aircraft to ensure ground personnel can verify the functionality of a missile’s [[flight termination system]] prior to launch. Such radar<del class="diffchange diffchange-inline"> </del>enhancing transponders are needed as the enclosed weapon bays on [[Fifth-generation jet fighter|modern aircraft]] interfere with prelaunch, flight termination system verification performed by [[range safety]] personnel during training test launches. The transponders re-radiate the signals allowing for much longer communication distances.<ref>{{Cite web|url=https://www.curtisswrightds.com/infocenter/white-papers/telemetry-re-radiation-system.html|title=TELEMETRY RE-RADIATION SYSTEM|last=Cook|first=Paul|date=2008|website=Curtiss-Wright Desfense Solutions}}</ref></div></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker"><a class="mw-diff-movedpara-right" title="Paragraph was moved. Click to jump to old location." href="#movedpara_17_0_lhs">⚫</a></td> <td class="diff-addedline diff-side-added"><div><a name="movedpara_19_0_rhs"></a>Transponders are used on some military aircraft to ensure ground personnel can verify the functionality of a missile’s [[flight termination system]] prior to launch. Such radar<ins class="diffchange diffchange-inline">-</ins>enhancing transponders are needed as the enclosed weapon bays on [[Fifth-generation jet fighter|modern aircraft]] interfere with prelaunch, flight termination system verification performed by [[range safety]] personnel during training test launches. The transponders re-radiate the signals allowing for much longer communication distances.<ref>{{Cite web|url=https://www.curtisswrightds.com/infocenter/white-papers/telemetry-re-radiation-system.html|title=TELEMETRY RE-RADIATION SYSTEM|last=Cook|first=Paul|date=2008|website=Curtiss-Wright Desfense Solutions}}</ref></div></td> </tr> <tr> <td class="diff-marker"><a class="mw-diff-movedpara-left" title="Paragraph was moved. Click to jump to new location." href="#movedpara_21_1_rhs">⚫</a></td> <td class="diff-deletedline diff-side-deleted"><div><a name="movedpara_20_0_lhs"></a>==Marine==</div></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><br /></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker"><a class="mw-diff-movedpara-right" title="Paragraph was moved. Click to jump to old location." href="#movedpara_20_0_lhs">⚫</a></td> <td class="diff-addedline diff-side-added"><div><a name="movedpara_21_1_rhs"></a><ins class="diffchange diffchange-inline">=</ins>==Marine<ins class="diffchange diffchange-inline">=</ins>==</div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>The [[International Maritime Organization]]'s [[International Convention for the Safety of Life at Sea]] (SOLAS) requires the [[Automatic Identification System]] (AIS) to be fitted aboard international voyaging ships with {{GT|300 or more|disp=long}}, and all passenger ships regardless of size.<ref>{{cite web</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>The [[International Maritime Organization]]'s [[International Convention for the Safety of Life at Sea]] (SOLAS) requires the [[Automatic Identification System]] (AIS) to be fitted aboard international voyaging ships with {{GT|300 or more|disp=long}}, and all passenger ships regardless of size.<ref>{{cite web</div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div> |work = [[International Convention for the Safety of Life at Sea|SOLAS]]'1974</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div> |work = [[International Convention for the Safety of Life at Sea|SOLAS]]'1974</div></td> </tr> <tr> <td colspan="2" class="diff-lineno">Line 39:</td> <td colspan="2" class="diff-lineno">Line 43:</td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div> |archive-url = http://arquivo.pt/wayback/20140725015425/http://www.imo.org/KnowledgeCentre/ReferencesAndArchives/HistoryofSOLAS/Documents/SOLAS%201974%20-%20Brief%20History%20-%20List%20of%20amendments%20to%20date%20and%20how%20to%20find%20them.html#43</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div> |archive-url = http://arquivo.pt/wayback/20140725015425/http://www.imo.org/KnowledgeCentre/ReferencesAndArchives/HistoryofSOLAS/Documents/SOLAS%201974%20-%20Brief%20History%20-%20List%20of%20amendments%20to%20date%20and%20how%20to%20find%20them.html#43</div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div> |archive-date = 2014-07-25</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div> |archive-date = 2014-07-25</div></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>}}</ref><del class="diffchange diffchange-inline"> Although</del> AIS transmitters/receivers are generally called transponders they generally transmit autonomously, although [[Coast radio station|coast stations]] can interrogate [[Automatic identification system#Detailed description: Class B units|class B transponders]] on smaller vessels for additional information. In addition, [[navigational aid]]s often have transponders called [[Racon|RACON]] (radar beacons) designed to make them stand out on a ship's radar screen.</div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>}}</ref> AIS transmitters/receivers are generally called <ins class="diffchange diffchange-inline">''</ins>transponders<ins class="diffchange diffchange-inline">'', but</ins> they generally transmit autonomously, although [[Coast radio station|coast stations]] can interrogate [[Automatic identification system#Detailed description: Class B units|class B transponders]] on smaller vessels for additional information.<ins class="diffchange diffchange-inline">{{cn|date=May 2024}}</ins> In addition, [[navigational aid]]s often have transponders called [[Racon|RACON]] (radar beacons) designed to make them stand out on a ship's radar screen.<ins class="diffchange diffchange-inline">{{cn|date=May 2024}}</ins></div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker"><a class="mw-diff-movedpara-right" title="Paragraph was moved. Click to jump to old location." href="#movedpara_39_2_lhs">⚫</a></td> <td class="diff-addedline diff-side-added"><div><a name="movedpara_25_0_rhs"></a>[[Sonar]] transponders operate under water and are used to measure distance and form the basis of underwater location marking, position tracking and [[navigation]].</div></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>==Automotive==</div></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>==Other applications==</div></td> </tr> <tr> <td class="diff-marker"><a class="mw-diff-movedpara-left" title="Paragraph was moved. Click to jump to new location." href="#movedpara_42_0_rhs">⚫</a></td> <td class="diff-deletedline diff-side-deleted"><div><a name="movedpara_28_0_lhs"></a>Many modern automobiles have keys with transponders hidden inside the plastic head of the key. The user of the car may not even be aware that the transponder is there, because there are no buttons to press. When a key is inserted into the ignition lock cylinder and turned, the car's computer sends a signal to the transponder. Unless the transponder replies with a valid code, the computer will not allow the engine to be started. Transponder keys have no battery; they are energized by the signal itself.<del class="diffchange diffchange-inline"> </del><ref>{{Cite web |url=http://carlocksmith.co/7-how-does-transponder-car-key-work.html |title=HOW DOES TRANSPONDER CAR KEY WORK?<del class="diffchange diffchange-inline">|</del> date=19 February 2015 }}</ref><ref>http://www.rfid-handbook.de/downloads/E2E_chapter03-rfid-handbook.pdf <del class="diffchange diffchange-inline">{{Bare</del> <del class="diffchange diffchange-inline">URL</del> <del class="diffchange diffchange-inline">PDF</del>|<del class="diffchange diffchange-inline">date</del>=<del class="diffchange diffchange-inline">March</del> <del class="diffchange diffchange-inline">2022</del>}}</ref></div></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>===Electronic toll collection===</div></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>==Road==</div></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>[[Electronic toll collection]] systems such as [[E-ZPass]] in the eastern United States use [[RFID]] transponders to identify vehicles.<del class="diffchange diffchange-inline"> [[Ontario Highway 407</del>|<del class="diffchange diffchange-inline">Highway 407]] in [[Ontario, Canada]], is one of the world's first completely automated toll</del> <del class="diffchange diffchange-inline">highways.</del></div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>[[Electronic toll collection]] systems such as [[E-ZPass]] in the eastern United States use [[RFID]] transponders to identify vehicles.<ins class="diffchange diffchange-inline">{{cn</ins>|<ins class="diffchange diffchange-inline">date=May</ins> <ins class="diffchange diffchange-inline">2024}}</ins></div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>==<del class="diffchange diffchange-inline">Motorsport</del>==</div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>==<ins class="diffchange diffchange-inline">=Lap timing=</ins>==</div></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>Transponders are used in <del class="diffchange diffchange-inline">[[motorsport]]</del> for lap timing<del class="diffchange diffchange-inline"> purposes</del>. A cable loop is dug into the race circuit near to the start/finish line. Each car has an active transponder with a unique ID code. When the <del class="diffchange diffchange-inline">racing car</del> passes the start/finish line the lap time and the racing position is shown on the score board.</div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>Transponders are used in <ins class="diffchange diffchange-inline">races</ins> for lap timing. A cable loop is dug into the race circuit near to the start/finish line. Each<ins class="diffchange diffchange-inline"> individual runner or</ins> car has an active transponder with a unique ID code. When the <ins class="diffchange diffchange-inline">individual</ins> passes the start/finish line<ins class="diffchange diffchange-inline">,</ins> the lap time and the racing position is shown on the score board.<ins class="diffchange diffchange-inline">{{cn|date=May 2024}}</ins></div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>Passive and active RFID systems are used in off-road events such as [[Enduro]] and [[Hare and Hound (Motorcycle Race)|Hare and Hounds]] racing, the riders have a transponder on their person, normally on their arm. When they complete a lap they swipe or touch the receiver which is connected to a computer and log their lap time.</div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>Passive and active RFID systems are used in<ins class="diffchange diffchange-inline"> [[motor sports]], and</ins> off-road events such as [[Enduro]] and [[Hare and Hound (Motorcycle Race)|Hare and Hounds]] racing, the riders have a transponder on their person, normally on their arm. When they complete a lap they swipe or touch the receiver which is connected to a computer and log their lap time.<ins class="diffchange diffchange-inline">{{cn|date=May 2024}}</ins></div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>[[NASCAR]] uses transponders and cable loops placed at numerous points around the track to determine the lineup during a caution period. This system replaced a dangerous [[Racing back to the caution|race back to the start-finish line]].</div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>[[NASCAR]] uses transponders and cable loops placed at numerous points around the track to determine the lineup during a caution period. This system replaced a dangerous [[Racing back to the caution|race back to the start-finish line]].<ins class="diffchange diffchange-inline">{{cn|date=May 2024}}</ins></div></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><br /></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>==Underwater==</div></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td class="diff-marker"><a class="mw-diff-movedpara-left" title="Paragraph was moved. Click to jump to new location." href="#movedpara_25_0_rhs">⚫</a></td> <td class="diff-deletedline diff-side-deleted"><div><a name="movedpara_39_2_lhs"></a>[[Sonar]] transponders operate under water and are used to measure distance and form the basis of underwater location marking, position tracking and [[navigation]].</div></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>==<del class="diffchange diffchange-inline">Gated</del> <del class="diffchange diffchange-inline">communities</del>==</div></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>==<ins class="diffchange diffchange-inline">=Car</ins> <ins class="diffchange diffchange-inline">keys=</ins>==</div></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker"><a class="mw-diff-movedpara-right" title="Paragraph was moved. Click to jump to old location." href="#movedpara_28_0_lhs">⚫</a></td> <td class="diff-addedline diff-side-added"><div><a name="movedpara_42_0_rhs"></a>Many modern automobiles have keys with transponders hidden inside the plastic head of the key. The user of the car may not even be aware that the transponder is there, because there are no buttons to press. When a key is inserted into the ignition lock cylinder and turned, the car's computer sends a signal to the transponder. Unless the transponder replies with a valid code, the computer will not allow the engine to be started. Transponder keys have no battery; they are energized by the signal itself.<ref>{{Cite web |url=http://carlocksmith.co/7-how-does-transponder-car-key-work.html |title=HOW DOES TRANSPONDER CAR KEY WORK? <ins class="diffchange diffchange-inline">|</ins>date=19 February 2015<ins class="diffchange diffchange-inline"> |access-date=2 May 2019 |archive-date=2 May 2019 |archive-url=https://web.archive.org/web/20190502135641/http://carlocksmith.co/7-how-does-transponder-car-key-work.html |url-status=dead</ins> }}</ref><ref><ins class="diffchange diffchange-inline">{{Cite web | url=</ins>http://www.rfid-handbook.de/downloads/E2E_chapter03-rfid-handbook.pdf <ins class="diffchange diffchange-inline">|</ins> <ins class="diffchange diffchange-inline">title=Fundamental Operating Principles</ins> |<ins class="diffchange diffchange-inline"> website</ins>=<ins class="diffchange diffchange-inline">www.rfid-handbook.de</ins> <ins class="diffchange diffchange-inline">| access-date=2024-07-26</ins>}}</ref></div></td> </tr> <tr> <td class="diff-marker"><a class="mw-diff-movedpara-left" title="Paragraph was moved. Click to jump to new location." href="#movedpara_44_2_rhs">⚫</a></td> <td class="diff-deletedline diff-side-deleted"><div><a name="movedpara_43_0_lhs"></a><del class="diffchange diffchange-inline">Transponders may also be used by residents to enter their [[gated community|gated communities]]. </del>However, having more than one transponder causes problems. If a resident's car with simple transponder is parked in the vicinity, any vehicle can come up to the automated gate, triggering the [[Identification friend or foe|gate interrogation signal]], which may get an acceptable response from the resident's car. Such units properly installed might involve [[beamforming]], unique transponders for each vehicle, or simply obliging vehicles to be stored away from the gate.</div></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>===Gated communities===</div></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td class="diff-addedline diff-side-added"><div>Transponders may also be used by residents to enter their [[gated community|gated communities]].{{cn|date=May 2024}} </div></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker"><a class="mw-diff-movedpara-right" title="Paragraph was moved. Click to jump to old location." href="#movedpara_43_0_lhs">⚫</a></td> <td class="diff-addedline diff-side-added"><div><a name="movedpara_44_2_rhs"></a>However, having more than one transponder causes problems. If a resident's car with simple transponder is parked in the vicinity, any vehicle can come up to the automated gate, triggering the [[Identification friend or foe|gate interrogation signal]], which may get an acceptable response from the resident's car. Such units properly installed might involve [[beamforming]], unique transponders for each vehicle, or simply obliging vehicles to be stored away from the gate.<ins class="diffchange diffchange-inline">{{cn|date=May 2024}}</ins></div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>==See also==</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>==See also==</div></td> </tr> <tr> <td colspan="2" class="diff-lineno">Line 85:</td> <td colspan="2" class="diff-lineno">Line 89:</td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>[[Category:Radio-frequency identification]]</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>[[Category:Radio-frequency identification]]</div></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>[[Category:Wireless]]</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>[[Category:Wireless]]</div></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td class="diff-deletedline diff-side-deleted"><div>[[Category:Portmanteaus]]</div></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><br /></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td class="diff-context diff-side-deleted"><div>[[fi:Toisiotutka#Toisiotutkavastain]]</div></td> <td class="diff-marker"></td> <td class="diff-context diff-side-added"><div>[[fi:Toisiotutka#Toisiotutkavastain]]</div></td> </tr> </table><hr class='diff-hr' id='mw-oldid' /> <h2 class='diff-currentversion-title'>Latest revision as of 04:34, 17 October 2024</h2> <div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Device that emits an identifying signal in response to a received signal</div> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:407_Transponder.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f8/407_Transponder.jpg/120px-407_Transponder.jpg" decoding="async" width="120" height="160" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f8/407_Transponder.jpg/180px-407_Transponder.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/f/f8/407_Transponder.jpg 2x" data-file-width="240" data-file-height="320" /></a><figcaption>A <a href="/wiki/Ontario_Highway_407" title="Ontario Highway 407">Highway 407</a> toll transponder</figcaption></figure> <p>In <a href="/wiki/Telecommunications" title="Telecommunications">telecommunications</a>, a <b>transponder</b> is a device that, upon receiving a signal, emits a different signal in response.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> The term is a <a href="/wiki/Blend_word" title="Blend word">blend</a> of <i>transmitter</i> and <i>responder</i>.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p><p>In <a href="/wiki/Air_navigation" title="Air navigation">air navigation</a> or <a href="/wiki/Radio_frequency_identification" class="mw-redirect" title="Radio frequency identification">radio frequency identification</a>, a <a href="/wiki/Transponder_(aeronautics)" title="Transponder (aeronautics)">flight transponder</a> is an automated <a href="/wiki/Transceiver" title="Transceiver">transceiver</a> in an aircraft that emits a coded identifying signal in response to an interrogating received signal. </p><p>In a <a href="/wiki/Communications_satellite" title="Communications satellite">communications satellite</a>, a <a href="/wiki/Transponder_(satellite_communications)" title="Transponder (satellite communications)">satellite transponder</a> receives signals over a range of uplink frequencies, usually from a <a href="/wiki/Satellite_ground_station" class="mw-redirect" title="Satellite ground station">satellite ground station</a>; the transponder amplifies them, and re-transmits them on a different set of downlink frequencies to receivers on Earth, often without changing the content of the received signal or signals. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Satellite/broadcast_communications"><span id="Satellite.2Fbroadcast_communications"></span>Satellite/broadcast communications</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Transponder&action=edit&section=1" title="Edit section: Satellite/broadcast communications"><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">See also: <a href="/wiki/Transponder_(satellite_communications)" title="Transponder (satellite communications)">Transponder (satellite communications)</a></div> <p>A <a href="/wiki/Communications_satellite" title="Communications satellite">communications satellite</a>’s <a href="/wiki/Communication_channel" title="Communication channel">channels</a> are called transponders because each is a separate <a href="/wiki/Transceiver" title="Transceiver">transceiver</a> or <a href="/wiki/Repeater" title="Repeater">repeater</a>. With <a href="/wiki/Digital_video" title="Digital video">digital video</a> <a href="/wiki/Data_compression" title="Data compression">data compression</a> and <a href="/wiki/Multiplexing" title="Multiplexing">multiplexing</a>, several <a href="/wiki/Video" title="Video">video</a> and <a href="/wiki/Sound_reproduction" class="mw-redirect" title="Sound reproduction">audio</a> channels may travel through a single transponder on a single <a href="/wiki/Wideband" title="Wideband">wideband</a> <a href="/wiki/Carrier_signal" class="mw-redirect" title="Carrier signal">carrier</a>. Original <a href="/wiki/Analog_video" class="mw-redirect" title="Analog video">analog video</a> only has one channel per transponder, with <a href="/wiki/Subcarrier" title="Subcarrier">subcarriers</a> for audio and automatic transmission identification service (<a href="/wiki/Automatic_Transmitter_Identification_System_(television)" title="Automatic Transmitter Identification System (television)">ATIS</a>). Non-multiplexed <a href="/wiki/Radio_station" class="mw-redirect" title="Radio station">radio stations</a> can also travel in <a href="/wiki/Single_channel_per_carrier" title="Single channel per carrier">single channel per carrier</a> (SCPC) mode, with multiple carriers (analog or digital) per transponder. This allows each station to transmit directly to the satellite, rather than paying for a whole transponder, or using <a href="/wiki/Landline" title="Landline">landlines</a> to send it to an <a href="/wiki/Earth_station_(communications)" class="mw-redirect" title="Earth station (communications)">earth station</a> for multiplexing with other stations. </p> <div class="mw-heading mw-heading2"><h2 id="Optical_communications">Optical communications</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Transponder&action=edit&section=2" title="Edit section: Optical communications"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In <a href="/wiki/Fiber-optic_communication" title="Fiber-optic communication">fiber-optic communications</a>, a transponder is the element that sends and receives the optical signal from a <a href="/wiki/Optical_fiber" title="Optical fiber">fiber</a>. A transponder is typically characterized by its data rate and the maximum distance the signal can travel. </p><p>The term "transponder" can apply to different items with important functional differences, mentioned across academic and commercial literature: </p> <ul><li>according to one description,<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> a transponder and <a href="/wiki/Transceiver" title="Transceiver">transceiver</a> are both functionally similar devices that convert a <a href="/wiki/Full-duplex" class="mw-redirect" title="Full-duplex">full-duplex</a> <i>electrical</i> signal into a full-duplex optical signal. The difference between the two is that transceivers interface electrically with the host system using a <i>serial</i> interface, whereas transponders use a <i>parallel</i> interface to do so. In this view, transponders provide easier-to-handle lower-rate parallel signals, but are bulkier and consume more power than transceivers.</li> <li>according to another description,<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> transceivers are limited to providing an <i>electrical-optical</i> function only (not differentiating between serial or parallel electrical interfaces), whereas transponders convert an optical signal at one <a href="/wiki/Wavelength" title="Wavelength">wavelength</a> to an optical signal at another wavelength (typically <a href="/wiki/Frequency_grid" title="Frequency grid">ITU standardized</a> for <a href="/wiki/DWDM" class="mw-redirect" title="DWDM">DWDM</a> communication). As such, transponders can be considered as two transceivers placed back-to-back. This view also seems to be held by, for example, <a href="/wiki/Fujitsu" title="Fujitsu">Fujitsu</a>.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup></li></ul> <p>As a result, differences in transponder functionality also might influence the functional description of related optical modules like transceivers and <a href="/wiki/Muxponder" title="Muxponder">muxponders</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Aviation">Aviation</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Transponder&action=edit&section=3" title="Edit section: Aviation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Further information: <a href="/wiki/Transponder_(aeronautics)" title="Transponder (aeronautics)">Transponder (aeronautics)</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Transponder_in_Private_Aircraft.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/cc/Transponder_in_Private_Aircraft.jpg/220px-Transponder_in_Private_Aircraft.jpg" decoding="async" width="220" height="290" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/cc/Transponder_in_Private_Aircraft.jpg/330px-Transponder_in_Private_Aircraft.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/cc/Transponder_in_Private_Aircraft.jpg/440px-Transponder_in_Private_Aircraft.jpg 2x" data-file-width="2758" data-file-height="3641" /></a><figcaption>A transponder in a private plane squawking 2000</figcaption></figure> <p>Another type of transponder occurs in <a href="/wiki/Identification_friend_or_foe" title="Identification friend or foe">identification friend or foe</a> (IFF) systems in <a href="/wiki/Military_aviation" title="Military aviation">military aviation</a> and in <a href="/wiki/Air_traffic_control" title="Air traffic control">air traffic control</a> <a href="/wiki/Secondary_surveillance_radar" title="Secondary surveillance radar">secondary surveillance radar</a> (beacon radar) systems for <a href="/wiki/General_aviation" title="General aviation">general aviation</a> and <a href="/wiki/Commercial_aviation" title="Commercial aviation">commercial aviation</a>.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> </p><p><a href="/wiki/Radar" title="Radar">Primary radar</a> works best with large all-metal aircraft, but not so well on small, composite aircraft. Its range is also limited by terrain and rain or snow and also detects unwanted objects such as automobiles, hills and trees. Furthermore, it cannot always estimate the altitude of an aircraft. <a href="/wiki/Secondary_radar" class="mw-redirect" title="Secondary radar">Secondary radar</a> overcomes these limitations but it depends on a transponder in the aircraft to respond to interrogations from the ground station to make the plane more visible.<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 2024)">citation needed</span></a></i>]</sup> </p><p>Depending on the type of interrogation, the transponder sends back a <a href="/wiki/Transponder_code" class="mw-redirect" title="Transponder code">transponder code</a> (or "squawk code", Mode A) or altitude information (Mode C) to help air traffic controllers to identify the aircraft and to maintain separation between planes. Another mode called Mode S (Mode Select) is designed to help avoiding over-interrogation of the transponder (having many radars in busy areas) and to allow automatic collision avoidance. Mode S transponders are <a href="/wiki/Backward_compatible" class="mw-redirect" title="Backward compatible">backward compatible</a> with Modes A and C. Mode S is mandatory in <a href="/wiki/Controlled_airspace" title="Controlled airspace">controlled airspace</a> in many countries. Some countries have also required, or are moving toward requiring, that all aircraft be equipped with Mode S, even in <a href="/wiki/Uncontrolled_airspace" title="Uncontrolled airspace">uncontrolled airspace</a>. However, in the field of general aviation there have been objections to these moves, because of the cost, size, limited benefit to the users in uncontrolled airspace, and, in the case of <a href="/wiki/Balloon_(aeronautics)" title="Balloon (aeronautics)">balloons</a> and <a href="/wiki/Glider_(sailplane)" title="Glider (sailplane)">gliders</a>, the power requirements during long flights.<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 2024)">citation needed</span></a></i>]</sup> </p><p>Transponders are used on some military aircraft to ensure ground personnel can verify the functionality of a missile’s <a href="/wiki/Flight_termination_system" class="mw-redirect" title="Flight termination system">flight termination system</a> prior to launch. Such radar-enhancing transponders are needed as the enclosed weapon bays on <a href="/wiki/Fifth-generation_jet_fighter" class="mw-redirect" title="Fifth-generation jet fighter">modern aircraft</a> interfere with prelaunch, flight termination system verification performed by <a href="/wiki/Range_safety" title="Range safety">range safety</a> personnel during training test launches. The transponders re-radiate the signals allowing for much longer communication distances.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Marine">Marine</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Transponder&action=edit&section=4" title="Edit section: Marine"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <a href="/wiki/International_Maritime_Organization" title="International Maritime Organization">International Maritime Organization</a>'s <a href="/wiki/International_Convention_for_the_Safety_of_Life_at_Sea" class="mw-redirect" title="International Convention for the Safety of Life at Sea">International Convention for the Safety of Life at Sea</a> (SOLAS) requires the <a href="/wiki/Automatic_Identification_System" class="mw-redirect" title="Automatic Identification System">Automatic Identification System</a> (AIS) to be fitted aboard international voyaging ships with 300 or more <a href="/wiki/Gross_tonnage" title="Gross tonnage">gross tonnage</a> (GT), and all passenger ships regardless of size.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> AIS transmitters/receivers are generally called <i>transponders</i>, but they generally transmit autonomously, although <a href="/wiki/Coast_radio_station" title="Coast radio station">coast stations</a> can interrogate <a href="/wiki/Automatic_identification_system#Detailed_description:_Class_B_units" title="Automatic identification system">class B transponders</a> on smaller vessels for additional information.<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 2024)">citation needed</span></a></i>]</sup> In addition, <a href="/wiki/Navigational_aid" title="Navigational aid">navigational aids</a> often have transponders called <a href="/wiki/Racon" class="mw-redirect" title="Racon">RACON</a> (radar beacons) designed to make them stand out on a ship's radar screen.<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 2024)">citation needed</span></a></i>]</sup> </p><p><a href="/wiki/Sonar" title="Sonar">Sonar</a> transponders operate under water and are used to measure distance and form the basis of underwater location marking, position tracking and <a href="/wiki/Navigation" title="Navigation">navigation</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Other_applications">Other applications</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Transponder&action=edit&section=5" title="Edit section: Other applications"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Electronic_toll_collection">Electronic toll collection</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Transponder&action=edit&section=6" title="Edit section: Electronic toll collection"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/Electronic_toll_collection" title="Electronic toll collection">Electronic toll collection</a> systems such as <a href="/wiki/E-ZPass" title="E-ZPass">E-ZPass</a> in the eastern United States use <a href="/wiki/RFID" class="mw-redirect" title="RFID">RFID</a> transponders to identify vehicles.<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 2024)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading3"><h3 id="Lap_timing">Lap timing</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Transponder&action=edit&section=7" title="Edit section: Lap timing"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Transponders are used in races for lap timing. A cable loop is dug into the race circuit near to the start/finish line. Each individual runner or car has an active transponder with a unique ID code. When the individual passes the start/finish line, the lap time and the racing position is shown on the score board.<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 2024)">citation needed</span></a></i>]</sup> </p><p>Passive and active RFID systems are used in <a href="/wiki/Motor_sports" class="mw-redirect" title="Motor sports">motor sports</a>, and off-road events such as <a href="/wiki/Enduro" title="Enduro">Enduro</a> and <a href="/w/index.php?title=Hare_and_Hound_(Motorcycle_Race)&action=edit&redlink=1" class="new" title="Hare and Hound (Motorcycle Race) (page does not exist)">Hare and Hounds</a> racing, the riders have a transponder on their person, normally on their arm. When they complete a lap they swipe or touch the receiver which is connected to a computer and log their lap time.<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 2024)">citation needed</span></a></i>]</sup> </p><p><a href="/wiki/NASCAR" title="NASCAR">NASCAR</a> uses transponders and cable loops placed at numerous points around the track to determine the lineup during a caution period. This system replaced a dangerous <a href="/wiki/Racing_back_to_the_caution" title="Racing back to the caution">race back to the start-finish line</a>.<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 2024)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading3"><h3 id="Car_keys">Car keys</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Transponder&action=edit&section=8" title="Edit section: Car keys"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Many modern automobiles have keys with transponders hidden inside the plastic head of the key. The user of the car may not even be aware that the transponder is there, because there are no buttons to press. When a key is inserted into the ignition lock cylinder and turned, the car's computer sends a signal to the transponder. Unless the transponder replies with a valid code, the computer will not allow the engine to be started. Transponder keys have no battery; they are energized by the signal itself.<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><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> <div class="mw-heading mw-heading3"><h3 id="Gated_communities">Gated communities</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Transponder&action=edit&section=9" title="Edit section: Gated communities"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Transponders may also be used by residents to enter their <a href="/wiki/Gated_community" title="Gated community">gated communities</a>.<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 2024)">citation needed</span></a></i>]</sup> However, having more than one transponder causes problems. If a resident's car with simple transponder is parked in the vicinity, any vehicle can come up to the automated gate, triggering the <a href="/wiki/Identification_friend_or_foe" title="Identification friend or foe">gate interrogation signal</a>, which may get an acceptable response from the resident's car. Such units properly installed might involve <a href="/wiki/Beamforming" title="Beamforming">beamforming</a>, unique transponders for each vehicle, or simply obliging vehicles to be stored away from the gate.<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 2024)">citation needed</span></a></i>]</sup> </p> <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=Transponder&action=edit&section=10" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Acronyms_and_abbreviations_in_avionics" class="mw-redirect" title="Acronyms and abbreviations in avionics">Acronyms and abbreviations in avionics</a></li> <li><a href="/wiki/Transponder_car_key" class="mw-redirect" title="Transponder car key">Transponder car key</a></li> <li><a href="/wiki/Transceiver" title="Transceiver">Transceiver</a></li> <li><a href="/wiki/Muxponder" title="Muxponder">Muxponder</a></li> <li><a href="/wiki/Rebecca/Eureka_transponding_radar" title="Rebecca/Eureka transponding radar">Rebecca/Eureka transponding radar</a></li></ul> <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=Transponder&action=edit&section=11" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles: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"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.merriam-webster.com/dictionary/transponder">"Definition of TRANSPONDER"</a>. 22 July 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Definition+of+TRANSPONDER&rft.date=2023-07-22&rft_id=https%3A%2F%2Fwww.merriam-webster.com%2Fdictionary%2Ftransponder&rfr_id=info%3Asid%2Fen.wikipedia.org%3ATransponder" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://dictionary.reference.com/browse/transponder">transponder</a></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="https://kunkune.co.uk/">"Kunkune"</a>. 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Archived from <a rel="nofollow" class="external text" href="http://www.compeng.dit.ie/staff/tfreir/optical_2/Unit_4.ppt">the original</a> on 2011-07-21<span class="reference-accessdate">. Retrieved <span class="nowrap">2011-02-16</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=WDM+and+DWDM+Multiplexing+Powerpoint+presentation%2C+School+of+Electronic+and+Communications+Engineering%2C+Dublin+%28Ireland%29%2C+slide+61&rft_id=http%3A%2F%2Fwww.compeng.dit.ie%2Fstaff%2Ftfreir%2Foptical_2%2FUnit_4.ppt&rfr_id=info%3Asid%2Fen.wikipedia.org%3ATransponder" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://www.fujitsu.com/downloads/TEL/fnc/pdfservices/DWDM_Tutorial.pdf">Fujitsu DWDM Primer, 2004</a></span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDobkin2005" class="citation journal cs1">Dobkin, Daniel M. 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Archived from <a rel="nofollow" class="external text" href="http://carlocksmith.co/7-how-does-transponder-car-key-work.html">the original</a> on 2 May 2019<span class="reference-accessdate">. Retrieved <span class="nowrap">2 May</span> 2019</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=HOW+DOES+TRANSPONDER+CAR+KEY+WORK%3F&rft.date=2015-02-19&rft_id=http%3A%2F%2Fcarlocksmith.co%2F7-how-does-transponder-car-key-work.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ATransponder" 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://www.rfid-handbook.de/downloads/E2E_chapter03-rfid-handbook.pdf">"Fundamental Operating Principles"</a> <span class="cs1-format">(PDF)</span>. <i>www.rfid-handbook.de</i><span class="reference-accessdate">. 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Archived from <a rel="nofollow" class="external text" href="https://www.its.bldrdoc.gov/fs-1037/fs-1037c.htm">the original</a> on 2022-01-22.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Federal+Standard+1037C&rft.pub=General+Services+Administration&rft_id=https%3A%2F%2Fwww.its.bldrdoc.gov%2Ffs-1037%2Ffs-1037c.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3ATransponder" class="Z3988"></span> (in support of <a href="/wiki/MIL-STD-188" title="MIL-STD-188">MIL-STD-188</a>).</span></li> <li><span class="noviewer" typeof="mw:File"><span><img alt="Public Domain" src="//upload.wikimedia.org/wikipedia/en/thumb/6/62/PD-icon.svg/12px-PD-icon.svg.png" decoding="async" width="12" height="12" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/6/62/PD-icon.svg/18px-PD-icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/6/62/PD-icon.svg/24px-PD-icon.svg.png 2x" data-file-width="196" data-file-height="196" /></span></span> This article incorporates <a href="/wiki/Copyright_status_of_works_by_the_federal_government_of_the_United_States" title="Copyright status of works by the federal government of the United States">public domain material</a> from <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs1"><i><a href="/wiki/Department_of_Defense_Dictionary_of_Military_and_Associated_Terms" title="Department of Defense Dictionary of Military and Associated Terms">Dictionary of Military and Associated Terms</a></i>. <a href="/wiki/United_States_Department_of_Defense" title="United States Department of Defense">United States Department of Defense</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Dictionary+of+Military+and+Associated+Terms&rft.pub=United+States+Department+of+Defense&rfr_id=info%3Asid%2Fen.wikipedia.org%3ATransponder" class="Z3988"></span></li></ul> <style 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