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> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en" class=""><span>Donate</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=ISDN" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=ISDN" title="You're encouraged to log in; however, it's not mandatory. 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class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-History" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#History"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>History</span> </div> </a> <button aria-controls="toc-History-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 History subsection</span> </button> <ul id="toc-History-sublist" class="vector-toc-list"> <li id="toc-Digital_lines" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Digital_lines"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.1</span> <span>Digital lines</span> </div> </a> <ul id="toc-Digital_lines-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Standardization" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Standardization"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.2</span> <span>Standardization</span> </div> </a> <ul id="toc-Standardization-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Rollout" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Rollout"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.3</span> <span>Rollout</span> </div> </a> <ul id="toc-Rollout-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Replacement_by_ADSL" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Replacement_by_ADSL"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.4</span> <span>Replacement by ADSL</span> </div> </a> <ul id="toc-Replacement_by_ADSL-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Design" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Design"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Design</span> </div> </a> <button aria-controls="toc-Design-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 Design subsection</span> </button> <ul id="toc-Design-sublist" class="vector-toc-list"> <li id="toc-Configurations" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Configurations"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Configurations</span> </div> </a> <ul id="toc-Configurations-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Reference_points" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Reference_points"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Reference points</span> </div> </a> <ul id="toc-Reference_points-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Basic_Rate_Interface" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Basic_Rate_Interface"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>Basic Rate Interface</span> </div> </a> <ul id="toc-Basic_Rate_Interface-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Primary_Rate_Interface" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Primary_Rate_Interface"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.4</span> <span>Primary Rate Interface</span> </div> </a> <ul id="toc-Primary_Rate_Interface-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Bearer_channel" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Bearer_channel"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.5</span> <span>Bearer channel</span> </div> </a> <ul id="toc-Bearer_channel-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-X.25" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#X.25"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.6</span> <span>X.25</span> </div> </a> <ul id="toc-X.25-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Frame_Relay" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Frame_Relay"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.7</span> <span>Frame Relay</span> </div> </a> <ul id="toc-Frame_Relay-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Uses" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Uses"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Uses</span> </div> </a> <button aria-controls="toc-Uses-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 Uses subsection</span> </button> <ul id="toc-Uses-sublist" class="vector-toc-list"> <li id="toc-Telephone_industry" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Telephone_industry"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Telephone industry</span> </div> </a> <ul id="toc-Telephone_industry-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Video_conferencing" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Video_conferencing"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Video conferencing</span> </div> </a> <ul id="toc-Video_conferencing-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Broadcast_industry" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Broadcast_industry"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>Broadcast industry</span> </div> </a> <ul id="toc-Broadcast_industry-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Backup_lines" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Backup_lines"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.4</span> <span>Backup lines</span> </div> </a> <ul id="toc-Backup_lines-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-International_deployment" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#International_deployment"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>International deployment</span> </div> </a> <button aria-controls="toc-International_deployment-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 International deployment subsection</span> </button> <ul id="toc-International_deployment-sublist" class="vector-toc-list"> <li id="toc-Australia" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Australia"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Australia</span> </div> </a> <ul id="toc-Australia-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-France" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#France"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>France</span> </div> </a> <ul id="toc-France-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Germany" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Germany"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.3</span> <span>Germany</span> </div> </a> <ul id="toc-Germany-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Greece" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Greece"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.4</span> <span>Greece</span> </div> </a> <ul id="toc-Greece-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-India" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#India"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.5</span> <span>India</span> </div> </a> <ul id="toc-India-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Japan" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Japan"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.6</span> <span>Japan</span> </div> </a> <ul id="toc-Japan-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Norway" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Norway"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.7</span> <span>Norway</span> </div> </a> <ul id="toc-Norway-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-United_Kingdom" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#United_Kingdom"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.8</span> <span>United Kingdom</span> </div> </a> <ul id="toc-United_Kingdom-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-United_States_and_Canada" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#United_States_and_Canada"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.9</span> <span>United States and Canada</span> </div> </a> <ul id="toc-United_States_and_Canada-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Notes" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Notes</span> </div> </a> <ul id="toc-Notes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</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"><span class="mw-page-title-main">ISDN</span></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 52 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-52" 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">52 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-af mw-list-item"><a href="https://af.wikipedia.org/wiki/Ge%C3%AFntegreerdedienste-_digitale_netwerk" title="Geïntegreerdedienste- digitale netwerk – Afrikaans" lang="af" hreflang="af" data-title="Geïntegreerdedienste- digitale netwerk" data-language-autonym="Afrikaans" data-language-local-name="Afrikaans" class="interlanguage-link-target"><span>Afrikaans</span></a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%B4%D8%A8%D9%83%D8%A9_%D8%B1%D9%82%D9%85%D9%8A%D8%A9_%D9%84%D9%84%D8%AE%D8%AF%D9%85%D8%A7%D8%AA_%D8%A7%D9%84%D9%85%D8%AA%D9%83%D8%A7%D9%85%D9%84%D8%A9" title="شبكة رقمية للخدمات المتكاملة – Arabic" lang="ar" hreflang="ar" data-title="شبكة رقمية للخدمات المتكاملة" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/%C4%B0nteqrasiya_Edilmi%C5%9F_R%C9%99q%C9%99msal_%C5%9E%C9%99b%C9%99k%C9%99" title="İnteqrasiya Edilmiş Rəqəmsal Şəbəkə – Azerbaijani" lang="az" hreflang="az" data-title="İnteqrasiya Edilmiş Rəqəmsal Şəbəkə" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%87%E0%A6%A8%E0%A7%8D%E0%A6%9F%E0%A6%BF%E0%A6%97%E0%A7%8D%E0%A6%B0%E0%A7%87%E0%A6%9F%E0%A7%87%E0%A6%A1_%E0%A6%B8%E0%A6%BE%E0%A6%B0%E0%A7%8D%E0%A6%AD%E0%A6%BF%E0%A6%B8%E0%A7%87%E0%A6%B8_%E0%A6%A1%E0%A6%BF%E0%A6%9C%E0%A6%BF%E0%A6%9F%E0%A6%BE%E0%A6%B2_%E0%A6%A8%E0%A7%87%E0%A6%9F%E0%A6%93%E0%A6%AF%E0%A6%BC%E0%A6%BE%E0%A6%B0%E0%A7%8D%E0%A6%95" title="ইন্টিগ্রেটেড সার্ভিসেস ডিজিটাল নেটওয়ার্ক – Bangla" lang="bn" hreflang="bn" data-title="ইন্টিগ্রেটেড সার্ভিসেস ডিজিটাল নেটওয়ার্ক" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-be-x-old mw-list-item"><a href="https://be-tarask.wikipedia.org/wiki/ISDN" title="ISDN – Belarusian (Taraškievica orthography)" lang="be-tarask" hreflang="be-tarask" data-title="ISDN" data-language-autonym="Беларуская (тарашкевіца)" data-language-local-name="Belarusian (Taraškievica orthography)" class="interlanguage-link-target"><span>Беларуская (тарашкевіца)</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%A6%D0%B8%D1%84%D1%80%D0%BE%D0%B2%D0%B0_%D0%BC%D1%80%D0%B5%D0%B6%D0%B0_%D1%81_%D0%B8%D0%BD%D1%82%D0%B5%D0%B3%D1%80%D0%B8%D1%80%D0%B0%D0%BD%D0%B8_%D1%83%D1%81%D0%BB%D1%83%D0%B3%D0%B8" title="Цифрова мрежа с интегрирани услуги – Bulgarian" lang="bg" hreflang="bg" data-title="Цифрова мрежа с интегрирани услуги" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/ISDN" title="ISDN – Bosnian" lang="bs" hreflang="bs" data-title="ISDN" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target"><span>Bosanski</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Xarxa_digital_de_serveis_integrats" title="Xarxa digital de serveis integrats – Catalan" lang="ca" hreflang="ca" data-title="Xarxa digital de serveis integrats" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/ISDN" title="ISDN – Czech" lang="cs" hreflang="cs" data-title="ISDN" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/ISDN" title="ISDN – Danish" lang="da" hreflang="da" data-title="ISDN" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de badge-Q17437796 badge-featuredarticle mw-list-item" title="featured article badge"><a href="https://de.wikipedia.org/wiki/Integrated_Services_Digital_Network" title="Integrated Services Digital Network – German" lang="de" hreflang="de" data-title="Integrated Services Digital Network" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/ISDN" title="ISDN – Greek" lang="el" hreflang="el" data-title="ISDN" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Red_digital_de_servicios_integrados" title="Red digital de servicios integrados – Spanish" lang="es" hreflang="es" data-title="Red digital de servicios integrados" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/ISDN-telefono" title="ISDN-telefono – Esperanto" lang="eo" hreflang="eo" data-title="ISDN-telefono" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/ISDN" title="ISDN – Basque" lang="eu" hreflang="eu" data-title="ISDN" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%B4%D8%A8%DA%A9%D9%87_%D8%AF%DB%8C%D8%AC%DB%8C%D8%AA%D8%A7%D9%84%DB%8C_%D8%AE%D8%AF%D9%85%D8%A7%D8%AA_%DB%8C%DA%A9%D9%BE%D8%A7%D8%B1%DA%86%D9%87" title="شبکه دیجیتالی خدمات یکپارچه – Persian" lang="fa" hreflang="fa" data-title="شبکه دیجیتالی خدمات یکپارچه" 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/R%C3%A9seau_num%C3%A9rique_%C3%A0_int%C3%A9gration_de_services" title="Réseau numérique à intégration de services – French" lang="fr" hreflang="fr" data-title="Réseau numérique à intégration de services" 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/L%C3%ADonra_digiteach_de_sheirbh%C3%ADs%C3%AD_ioml%C3%A1naithe" title="Líonra digiteach de sheirbhísí iomlánaithe – Irish" lang="ga" hreflang="ga" data-title="Líonra digiteach de sheirbhísí iomlánaithe" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/RDSI" title="RDSI – Galician" lang="gl" hreflang="gl" data-title="RDSI" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EC%A2%85%ED%95%A9_%EC%A0%95%EB%B3%B4_%ED%86%B5%EC%8B%A0%EB%A7%9D" title="종합 정보 통신망 – Korean" lang="ko" hreflang="ko" data-title="종합 정보 통신망" 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%86%E0%A4%87%E0%A4%8F%E0%A4%B8%E0%A4%A1%E0%A5%80%E0%A4%8F%E0%A4%A8_(ISDN)" title="आइएसडीएन (ISDN) – Hindi" lang="hi" hreflang="hi" data-title="आइएसडीएन (ISDN)" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/ISDN" title="ISDN – Croatian" lang="hr" hreflang="hr" data-title="ISDN" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Jaringan_Digital_Pelayanan_Terpadu" title="Jaringan Digital Pelayanan Terpadu – Indonesian" lang="id" hreflang="id" data-title="Jaringan Digital Pelayanan Terpadu" 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/Integrated_Services_Digital_Network" title="Integrated Services Digital Network – Italian" lang="it" hreflang="it" data-title="Integrated Services Digital Network" 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/ISDN" title="ISDN – Hebrew" lang="he" hreflang="he" data-title="ISDN" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/ISDN" title="ISDN – Kazakh" lang="kk" hreflang="kk" data-title="ISDN" data-language-autonym="Қазақша" data-language-local-name="Kazakh" class="interlanguage-link-target"><span>Қазақша</span></a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/ISDN" title="ISDN – Latvian" lang="lv" hreflang="lv" data-title="ISDN" data-language-autonym="Latviešu" data-language-local-name="Latvian" class="interlanguage-link-target"><span>Latviešu</span></a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/ISDN" title="ISDN – Lithuanian" lang="lt" hreflang="lt" data-title="ISDN" data-language-autonym="Lietuvių" data-language-local-name="Lithuanian" class="interlanguage-link-target"><span>Lietuvių</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/ISDN_telefon" title="ISDN telefon – Hungarian" lang="hu" hreflang="hu" data-title="ISDN telefon" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%94%D0%B8%D0%B3%D0%B8%D1%82%D0%B0%D0%BB%D0%BD%D0%B0_%D0%BC%D1%80%D0%B5%D0%B6%D0%B0_%D0%BD%D0%B0_%D0%B8%D0%BD%D1%82%D0%B5%D0%B3%D1%80%D0%B8%D1%80%D0%B0%D0%BD%D0%B8_%D1%83%D1%81%D0%BB%D1%83%D0%B3%D0%B8" title="Дигитална мрежа на интегрирани услуги – Macedonian" lang="mk" hreflang="mk" data-title="Дигитална мрежа на интегрирани услуги" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%87%E0%B4%A8%E0%B5%8D%E0%B4%B1%E2%80%8C%E0%B4%97%E0%B5%8D%E0%B4%B0%E0%B5%87%E0%B4%B1%E0%B5%8D%E0%B4%B1%E0%B4%A1%E0%B5%8D_%E0%B4%B8%E0%B5%BC%E0%B4%B5%E0%B5%80%E0%B4%B8%E0%B4%B8%E0%B5%8D_%E0%B4%A1%E0%B4%BF%E0%B4%9C%E0%B4%BF%E0%B4%B1%E0%B5%8D%E0%B4%B1%E0%B5%BD_%E0%B4%A8%E0%B5%86%E0%B4%B1%E0%B5%8D%E0%B4%B1%E0%B5%8D%E2%80%8C%E0%B4%B5%E0%B5%BC%E0%B4%95%E0%B5%8D%E0%B4%95%E0%B5%8D" title="ഇന്റ‌ഗ്രേറ്റഡ് സർവീസസ് ഡിജിറ്റൽ നെറ്റ്‌വർക്ക് – Malayalam" lang="ml" hreflang="ml" data-title="ഇന്റ‌ഗ്രേറ്റഡ് സർവീസസ് ഡിജിറ്റൽ നെറ്റ്‌വർക്ക്" 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/ISDN" title="ISDN – Malay" lang="ms" hreflang="ms" data-title="ISDN" 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-my mw-list-item"><a href="https://my.wikipedia.org/wiki/%E1%80%9D%E1%80%94%E1%80%BA%E1%80%86%E1%80%B1%E1%80%AC%E1%80%84%E1%80%BA%E1%80%99%E1%80%BE%E1%80%AF%E1%80%99%E1%80%BB%E1%80%AC%E1%80%B8%E1%80%85%E1%80%AF%E1%80%85%E1%80%8A%E1%80%BA%E1%80%B8%E1%80%91%E1%80%AC%E1%80%B8%E1%80%9E%E1%80%B1%E1%80%AC_%E1%80%92%E1%80%AE%E1%80%82%E1%80%BB%E1%80%85%E1%80%BA%E1%80%90%E1%80%9A%E1%80%BA%E1%80%80%E1%80%BD%E1%80%94%E1%80%BA%E1%80%9A%E1%80%80%E1%80%BA" title="ဝန်ဆောင်မှုများစုစည်းထားသော ဒီဂျစ်တယ်ကွန်ယက် – Burmese" lang="my" hreflang="my" data-title="ဝန်ဆောင်မှုများစုစည်းထားသော ဒီဂျစ်တယ်ကွန်ယက်" data-language-autonym="မြန်မာဘာသာ" data-language-local-name="Burmese" class="interlanguage-link-target"><span>မြန်မာဘာသာ</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Integrated_services_digital_network" title="Integrated services digital network – Dutch" lang="nl" hreflang="nl" data-title="Integrated services digital network" 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/ISDN" title="ISDN – Japanese" lang="ja" hreflang="ja" data-title="ISDN" 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/ISDN" title="ISDN – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="ISDN" 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-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Integrated_Services_Digital_Network" title="Integrated Services Digital Network – Polish" lang="pl" hreflang="pl" data-title="Integrated Services Digital Network" 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/Rede_Digital_de_Servi%C3%A7os_Integrados" title="Rede Digital de Serviços Integrados – Portuguese" lang="pt" hreflang="pt" data-title="Rede Digital de Serviços Integrados" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/ISDN" title="ISDN – Romanian" lang="ro" hreflang="ro" data-title="ISDN" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/ISDN" title="ISDN – Russian" lang="ru" hreflang="ru" data-title="ISDN" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Integrated_Services_Digital_Network" title="Integrated Services Digital Network – Simple English" lang="en-simple" hreflang="en-simple" data-title="Integrated Services Digital Network" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Digit%C3%A1lna_sie%C5%A5_integrovan%C3%BDch_slu%C5%BEieb" title="Digitálna sieť integrovaných služieb – Slovak" lang="sk" hreflang="sk" data-title="Digitálna sieť integrovaných služieb" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/ISDN" title="ISDN – Slovenian" lang="sl" hreflang="sl" data-title="ISDN" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/ISDN" title="ISDN – Serbian" lang="sr" hreflang="sr" data-title="ISDN" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/ISDN" title="ISDN – Serbo-Croatian" lang="sh" hreflang="sh" data-title="ISDN" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="Serbo-Croatian" class="interlanguage-link-target"><span>Srpskohrvatski / српскохрватски</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/ISDN" title="ISDN – Finnish" lang="fi" hreflang="fi" data-title="ISDN" 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/Integrated_Services_Digital_Network" title="Integrated Services Digital Network – Swedish" lang="sv" hreflang="sv" data-title="Integrated Services Digital Network" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%92%E0%AE%B0%E0%AF%81%E0%AE%99%E0%AF%8D%E0%AE%95%E0%AE%BF%E0%AE%A3%E0%AF%88_%E0%AE%9A%E0%AF%87%E0%AE%B5%E0%AF%88_%E0%AE%8E%E0%AE%A3%E0%AF%8D%E0%AE%AE_%E0%AE%B5%E0%AE%B2%E0%AF%88%E0%AE%AF%E0%AE%AE%E0%AF%88%E0%AE%AA%E0%AF%8D%E0%AE%AA%E0%AF%81" title="ஒருங்கிணை சேவை எண்ம வலையமைப்பு – Tamil" lang="ta" hreflang="ta" data-title="ஒருங்கிணை சேவை எண்ம வலையமைப்பு" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target"><span>தமிழ்</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/ISDN" title="ISDN – Turkish" lang="tr" hreflang="tr" data-title="ISDN" 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/ISDN" title="ISDN – Ukrainian" lang="uk" hreflang="uk" data-title="ISDN" 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/ISDN" title="ISDN – Vietnamese" lang="vi" hreflang="vi" data-title="ISDN" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E7%BB%BC%E5%90%88%E4%B8%9A%E5%8A%A1%E6%95%B0%E5%AD%97%E7%BD%91" title="综合业务数字网 – Chinese" lang="zh" hreflang="zh" data-title="综合业务数字网" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q170397#sitelinks-wikipedia" title="Edit 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id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Set of digital telephony standards</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">For other uses, see <a href="/wiki/ISDN_(disambiguation)" class="mw-disambig" title="ISDN (disambiguation)">ISDN (disambiguation)</a>.</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Not to be confused with <a href="/wiki/Software-defined_networking" title="Software-defined networking">SDN (Software-defined networking)</a>.</div> <p class="mw-empty-elt"> </p> <style data-mw-deduplicate="TemplateStyles:r1257001546">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data:not(.notheme) div:not(.notheme){background:#1f1f23!important;color:#f8f9fa}}@media(min-width:640px){body.skin--responsive .mw-parser-output .infobox-table{display:table!important}body.skin--responsive .mw-parser-output .infobox-table>caption{display:table-caption!important}body.skin--responsive .mw-parser-output .infobox-table>tbody{display:table-row-group}body.skin--responsive .mw-parser-output .infobox-table tr{display:table-row!important}body.skin--responsive .mw-parser-output .infobox-table th,body.skin--responsive .mw-parser-output .infobox-table td{padding-left:inherit;padding-right:inherit}}</style><table class="infobox hproduct"><caption class="infobox-title fn">ISDN</caption><tbody><tr><td colspan="2" class="infobox-subheader">Integrated Services Digital Network</td></tr><tr><th scope="row" class="infobox-label">Year started</th><td class="infobox-data">1980<span class="noprint">; 44 years ago</span><span style="display:none"> (<span class="dtend">1980</span>)</span></td></tr><tr><th scope="row" class="infobox-label">First published</th><td class="infobox-data">1988<span class="noprint">; 36 years ago</span><span style="display:none"> (<span class="dtend">1988</span>)</span> <sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>a<span class="cite-bracket">]</span></a></sup></td></tr><tr><th scope="row" class="infobox-label">Organization</th><td class="infobox-data"><a href="/wiki/ITU-T" title="ITU-T">ITU-T</a></td></tr><tr><th scope="row" class="infobox-label">Predecessor</th><td class="infobox-data"><a href="/wiki/Plain_old_telephone_service" title="Plain old telephone service">Plain old telephone service</a> with <a href="/wiki/Dial-up_Internet_access" title="Dial-up Internet access">dial-up Internet access</a></td></tr><tr><th scope="row" class="infobox-label">Successor</th><td class="infobox-data"><a href="/wiki/Broadband" title="Broadband">Broadband</a> such as <a href="/wiki/Digital_subscriber_line" title="Digital subscriber line">DSL</a> or <a href="/wiki/FTTx" class="mw-redirect" title="FTTx">FTTx</a></td></tr></tbody></table> <style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist 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Protocol">RIP</a></li> <li><a href="/wiki/Session_Initiation_Protocol" title="Session Initiation Protocol">SIP</a></li> <li><a href="/wiki/Simple_Mail_Transfer_Protocol" title="Simple Mail Transfer Protocol">SMTP</a></li> <li><a href="/wiki/Simple_Network_Management_Protocol" title="Simple Network Management Protocol">SNMP</a></li> <li><a href="/wiki/Secure_Shell" title="Secure Shell">SSH</a></li> <li><a href="/wiki/Telnet" title="Telnet">Telnet</a></li> <li><a href="/wiki/Transport_Layer_Security" title="Transport Layer Security">TLS/SSL</a></li> <li><a href="/wiki/XMPP" title="XMPP">XMPP</a></li> <li><a href="/wiki/Category:Application_layer_protocols" title="Category:Application layer protocols"><i>more...</i></a></li></ul></td> </tr><tr><th class="sidebar-heading"> <a href="/wiki/Transport_layer" title="Transport layer">Transport layer</a></th></tr><tr><td class="sidebar-content"> <ul><li><a href="/wiki/Transmission_Control_Protocol" title="Transmission Control 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href="/wiki/Internet_Control_Message_Protocol" title="Internet Control Message Protocol">ICMP</a> (<a href="/wiki/ICMPv6" title="ICMPv6">v6</a>)</li> <li><a href="/wiki/Neighbor_Discovery_Protocol" title="Neighbor Discovery Protocol">NDP</a></li> <li><a href="/wiki/Explicit_Congestion_Notification" title="Explicit Congestion Notification">ECN</a></li> <li><a href="/wiki/Internet_Group_Management_Protocol" title="Internet Group Management Protocol">IGMP</a></li> <li><a href="/wiki/IPsec" title="IPsec">IPsec</a></li> <li><a href="/wiki/Category:Internet_layer_protocols" title="Category:Internet layer protocols"><i>more...</i></a></li></ul></td> </tr><tr><th class="sidebar-heading"> <a href="/wiki/Link_layer" title="Link layer">Link layer</a></th></tr><tr><td class="sidebar-content"> <ul><li><a href="/wiki/Address_Resolution_Protocol" title="Address Resolution Protocol">ARP</a></li> <li><a href="/wiki/Tunneling_protocol" title="Tunneling protocol">Tunnels</a></li> <li><a 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a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Internet_protocol_suite" title="Template:Internet protocol suite"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Internet_protocol_suite" title="Template talk:Internet protocol suite"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Internet_protocol_suite" title="Special:EditPage/Template:Internet protocol suite"><abbr title="Edit this template">e</abbr></a></li></ul></div></td></tr></tbody></table> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:ISDN_telefono.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/69/ISDN_telefono.jpg/220px-ISDN_telefono.jpg" decoding="async" width="220" height="203" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/69/ISDN_telefono.jpg/330px-ISDN_telefono.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/69/ISDN_telefono.jpg/440px-ISDN_telefono.jpg 2x" data-file-width="1578" data-file-height="1458" /></a><figcaption>ISDN telephone</figcaption></figure> <p><b>Integrated Services Digital Network</b> (<b>ISDN</b>) is a set of communication standards for simultaneous <a href="/wiki/Digital_data" title="Digital data">digital</a> <a href="/wiki/Transmission_(telecommunications)" class="mw-redirect" title="Transmission (telecommunications)">transmission</a> of voice, video, data, and other network services over the digitalised circuits of the <a href="/wiki/Public_switched_telephone_network" title="Public switched telephone network">public switched telephone network</a>.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> Work on the standard began in 1980 at <a href="/wiki/Bell_Labs" title="Bell Labs">Bell Labs</a> and was formally standardized in 1988 in the <a href="/wiki/ITU-T" title="ITU-T">CCITT</a> "Red Book".<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> By the time the standard was released, newer networking systems with much greater speeds were available, and ISDN saw relatively little uptake in the wider market. One estimate suggests ISDN use peaked at a worldwide total of 25 million subscribers at a time when 1.3 billion analog lines were in use.<sup id="cite_ref-FOOTNOTECioffi201130_4-0" class="reference"><a href="#cite_note-FOOTNOTECioffi201130-4"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> ISDN has largely been replaced with <a href="/wiki/Digital_subscriber_line" title="Digital subscriber line">digital subscriber line</a> (DSL) systems of much higher performance. </p><p>Prior to ISDN, the telephone system consisted of digital links like <a href="/wiki/T-carrier" title="T-carrier">T1</a>/<a href="/wiki/E-carrier" title="E-carrier">E1</a> on the long-distance lines between telephone company offices and analog signals on <a href="/wiki/Twisted_pair" title="Twisted pair">copper telephone wires</a> to the customers, the "<a href="/wiki/Last_mile_(telecommunications)" title="Last mile (telecommunications)">last mile</a>". At the time, the network was viewed as a way to transport voice, with some special services available for data using additional equipment like <a href="/wiki/Modem" title="Modem">modems</a> or by providing a T1 on the customer's location. What became ISDN started as an effort to digitize the last mile, originally under the name "Public Switched Digital Capacity" (PSDC).<sup id="cite_ref-FOOTNOTECioffi201130_4-1" class="reference"><a href="#cite_note-FOOTNOTECioffi201130-4"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> This would allow call routing to be completed in an all-digital system, while also offering a separate data line. The <a href="/wiki/Basic_Rate_Interface" title="Basic Rate Interface">Basic Rate Interface</a>, or BRI, is the standard last-mile connection in the ISDN system, offering two 64 kbit/s "bearer" lines and a single 16 kbit/s "data" channel for commands and data. </p><p>Although ISDN was successful in a few countries such as Germany, on a global scale the system was largely ignored and garnered the industry nickname "innovation subscribers didn't need."<sup id="cite_ref-FOOTNOTECioffi201131_5-0" class="reference"><a href="#cite_note-FOOTNOTECioffi201131-5"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> It found a use for a time for small-office digital connection, using the voice lines for data at 64 kbit/s, sometimes "bonded" to 128 kbit/s, but the introduction of 56 kbit/s modems undercut its value in many roles. It also found use in <a href="/wiki/Videoconference" class="mw-redirect" title="Videoconference">videoconference</a> systems, where the direct end-to-end connection was desirable. The <a href="/wiki/H.320" title="H.320">H.320</a> standard was designed around its 64 kbit/s data rate. The underlying ISDN concepts found wider use as a replacement for the T1/E1 lines it was originally intended to extend, roughly doubling the performance of those lines. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="History">History</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=1" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Digital_lines">Digital lines</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=2" title="Edit section: Digital lines"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Since its introduction in 1881, the <a href="/wiki/Twisted_pair" title="Twisted pair">twisted pair</a> copper line has been installed for telephone use worldwide, with well over a billion individual connections installed by the year 2000. Over the first half of the 20th century, the connection of these lines to form calls was increasingly automated, culminating in the <a href="/wiki/Crossbar_switch" title="Crossbar switch">crossbar switches</a> that had largely replaced earlier concepts by the 1950s.<sup id="cite_ref-FOOTNOTECioffi201130_4-2" class="reference"><a href="#cite_note-FOOTNOTECioffi201130-4"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p><p>As telephone use surged in the post-WWII era, the problem of connecting the massive number of lines became an area of significant study. <a href="/wiki/Bell_Labs" title="Bell Labs">Bell Labs</a>' seminal work on digital encoding of voice led to the use of 64 kbit/s as a standard for voice lines (or 56 kbit/s in some systems). In 1962, Robert Aaron of Bell introduced the T1 system, which carried 1.544 Mbit/s of data on a pair of twisted pair lines over a distance of about one mile. This was used in the Bell network to carry traffic between local switch offices, with 24 voice lines at 64 kbit/s and a separate 8 kbit/s line for signaling commands like connecting or hanging up a call. This could be extended over long distances using repeaters in the lines. T1 used a very simple encoding scheme, <a href="/wiki/Alternate_mark_inversion" class="mw-redirect" title="Alternate mark inversion">alternate mark inversion</a> (AMI), which reached only a few percent of the <a href="/wiki/Noisy-channel_coding_theorem" title="Noisy-channel coding theorem">theoretical capacity of the line</a> but was appropriate for 1960s electronics.<sup id="cite_ref-FOOTNOTECioffi201131_5-1" class="reference"><a href="#cite_note-FOOTNOTECioffi201131-5"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p><p>By the late 1970s, T1 lines and their faster counterparts, along with all-digital switching systems, had replaced the earlier analog systems for most of the western world, leaving only the customer's equipment and their local <a href="/wiki/Class-5_telephone_switch" title="Class-5 telephone switch">end office</a> using analog systems. Digitizing this "<a href="/wiki/Last_mile_(telecommunications)" title="Last mile (telecommunications)">last mile</a>" was increasingly seen as the next problem that needed to be solved. However, these connections now represented over 99% of the total telephony network, as the upstream links had increasingly been aggregated into a smaller number of much higher performance systems, especially after the introduction of <a href="/wiki/Fiber_optic" class="mw-redirect" title="Fiber optic">fiber optic</a> lines. If the system was to become all-digital, a new standard would be needed that was appropriate for the existing customer lines, which might be miles long and of widely varying quality.<sup id="cite_ref-FOOTNOTECioffi201131_5-2" class="reference"><a href="#cite_note-FOOTNOTECioffi201131-5"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Standardization">Standardization</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=3" title="Edit section: Standardization"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Around 1978, Ralph Wyndrum, Barry Bossick and Joe Lechleider of <a href="/wiki/Bell_Labs" title="Bell Labs">Bell Labs</a> began one such effort to develop a last-mile solution. They studied a number of derivatives of the T1's AMI concept and concluded that a customer-side line could reliably carry about 160 kbit/s of data over a distance of 4 to 5 miles (6.4 to 8.0 km). That would be enough to carry two voice-quality lines at 64 kbit/s as well as a separate 16 kbit/s line for data. At the time, <a href="/wiki/Modem" title="Modem">modems</a> were normally 300 bit/s and 1200 bit/s would not become common until the early 1980s and the 2400 bit/s standard would not be completed until 1984. In this market, 16 kbit/s represented a significant advance in performance in addition to being a separate channel that coexists with voice channels.<sup id="cite_ref-FOOTNOTECioffi201131_5-3" class="reference"><a href="#cite_note-FOOTNOTECioffi201131-5"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p><p>A key problem was that the customer might only have a single twisted pair line to the location of the handset, so the solution used in T1 with separate upstream and downstream connections was not universally available. With analog connections, the solution was to use <a href="/wiki/Echo_cancellation" class="mw-redirect" title="Echo cancellation">echo cancellation</a>, but at the much higher bandwidth of the new concept, this would not be so simple. A debate broke out between teams worldwide about the best solution to this problem; some promoted newer versions of echo cancellation, while others preferred the "ping pong" concept where the direction of data would rapidly switch the line from send to receive at such a high rate it would not be noticeable to the user. <a href="/wiki/John_Cioffi" title="John Cioffi">John Cioffi</a> had recently demonstrated echo cancellation would work at these speeds, and further suggested that they should consider moving directly to 1.5 Mbit/s performance using this concept. The suggestion was literally laughed off the table (His boss told him to "sit down and shut up"<sup id="cite_ref-FOOTNOTECioffi201131_5-4" class="reference"><a href="#cite_note-FOOTNOTECioffi201131-5"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup>) but the echo cancellation concept that was taken up by Joe Lechleider eventually came to win the debate.<sup id="cite_ref-FOOTNOTECioffi201131_5-5" class="reference"><a href="#cite_note-FOOTNOTECioffi201131-5"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p><p>Meanwhile, the debate over the encoding scheme itself was also ongoing. As the new standard was to be international, this was even more contentious as several regional digital standards had emerged in the 1960s and 70s and merging them was not going to be easy. To further confuse issues, in 1984 the <a href="/wiki/Breakup_of_the_Bell_System" title="Breakup of the Bell System">Bell System was broken up</a> and the US center for development moved to the <a href="/wiki/American_National_Standards_Institute" title="American National Standards Institute">American National Standards Institute</a> (ANSI) T1D1.3 committee. Thomas Starr of the newly formed <a href="/wiki/Ameritech" title="Ameritech">Ameritech</a> led this effort and eventually convinced the ANSI group to select the <a href="/wiki/2B1Q" title="2B1Q">2B1Q</a> standard proposed by Peter Adams of <a href="/wiki/British_Telecom" class="mw-redirect" title="British Telecom">British Telecom</a>. This standard used an 80 kHz base frequency and encoded two bits per baud to produce the 160 kbit/s base rate. Ultimately Japan selected a different standard, and Germany selected one with three levels instead of four, but all of these could interchange with the ANSI standard.<sup id="cite_ref-FOOTNOTECioffi201132_6-0" class="reference"><a href="#cite_note-FOOTNOTECioffi201132-6"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p><p>From an economic perspective, the <a href="/wiki/European_Commission" title="European Commission">European Commission</a> sought to liberalize and regulate ISDN across the <a href="/wiki/European_Economic_Community" title="European Economic Community">European Economic Community</a>.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> The <a href="/wiki/Council_of_the_European_Communities" class="mw-redirect" title="Council of the European Communities">Council of the European Communities</a> adopted Council Recommendation <a rel="nofollow" class="external text" href="https://eur-lex.europa.eu/eli/reco/1986/659">86/659/EEC</a><sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> in December 1986 for its coordinated introduction within the framework of CEPT. <a href="/wiki/ETSI" class="mw-redirect" title="ETSI">ETSI</a> (the European Telecommunications Standards Institute) was created by CEPT in 1988 and would develop the framework. </p> <div class="mw-heading mw-heading3"><h3 id="Rollout">Rollout</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=4" title="Edit section: Rollout"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>With digital-quality voice made possible by ISDN, offering two separate lines and continuous data connectivity, there was an initial global expectation of high customer demand for such systems in both the home and office environments. This expectation was met with varying degrees of success across different regions. </p><p>In the United States, many changes in the market led to the introduction of ISDN being tepid. During the lengthy standardization process, new concepts rendered the system largely superfluous. In the office, multi-line digital switches like the <a href="/wiki/Meridian_Norstar" class="mw-redirect" title="Meridian Norstar">Meridian Norstar</a> took over telephone lines while <a href="/wiki/Local_area_network" title="Local area network">local area networks</a> like <a href="/wiki/Ethernet" title="Ethernet">Ethernet</a> provided performance around 10 Mbit/s which had become the baseline for inter-computer connections in offices. ISDN offered no real advantages in the voice role and was far from competitive in data. Additionally, modems had continued improving, introducing 9600 bit/s systems in the late 1980s and 14.4 kbit/s in 1991, which significantly eroded ISDN's value proposition for the home customer.<sup id="cite_ref-FOOTNOTECioffi201132_6-1" class="reference"><a href="#cite_note-FOOTNOTECioffi201132-6"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p><p>Conversely, in Europe, ISDN found fertile ground for deployment, driven by regulatory support, infrastructural needs, and the absence of comparable high-speed communication technologies at the time. The technology was widely embraced for its ability to digitalize the "last mile" of telecommunications, significantly enhancing the quality and efficiency of voice, data, and video transmission over traditional analog systems. </p><p>Meanwhile, Lechleider had proposed using ISDN's echo cancellation and 2B1Q encoding on existing T1 connections so that the distance between repeaters could be doubled to about 2 miles (3.2 km). Another <a href="/wiki/Standards_war" class="mw-redirect" title="Standards war">standards war</a> broke out, but in 1991 Lechleider's 1.6 Mbit/s "High-Speed Digital Subscriber Line" eventually won this process as well, after Starr drove it through the ANSI T1E1.4 group. A similar standard emerged in Europe to replace their E1 lines, increasing the sampling range from 80 to 100 kHz to achieve 2.048 Mbit/s.<sup id="cite_ref-FOOTNOTECioffi201134_9-0" class="reference"><a href="#cite_note-FOOTNOTECioffi201134-9"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> By the mid-1990s, these <a href="/wiki/Primary_Rate_Interface" title="Primary Rate Interface">Primary Rate Interface</a> (PRI) lines had largely replaced T1 and E1 between telephone company offices. </p> <div class="mw-heading mw-heading3"><h3 id="Replacement_by_ADSL">Replacement by ADSL</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=5" title="Edit section: Replacement by ADSL"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Lechleider also believed this higher-speed standard would be much more attractive to customers than ISDN had proven. Unfortunately, at these speeds, the systems suffered from a type of <a href="/wiki/Crosstalk" title="Crosstalk">crosstalk</a> known as "NEXT", for "near-end crosstalk". This made longer connections on customer lines difficult. Lechleider noted that NEXT only occurred when similar frequencies were being used, and could be diminished if one of the directions used a different carrier rate, but doing so would reduce the potential bandwidth of that channel. Lechleider suggested that most consumer use would be asymmetric anyway, and that providing a high-speed channel towards the user and a lower speed return would be suitable for many uses.<sup id="cite_ref-FOOTNOTECioffi201134_9-1" class="reference"><a href="#cite_note-FOOTNOTECioffi201134-9"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p><p>This work in the early 1990s eventually led to the <a href="/wiki/ADSL" title="ADSL">ADSL</a> concept, which emerged in 1995. An early supporter of the concept was <a href="/wiki/Alcatel" title="Alcatel">Alcatel</a>, who jumped on ADSL while many other companies were still devoted to ISDN. Krish Prabu stated that "Alcatel will have to invest one billion dollars in ADSL before it makes a profit, but it is worth it." They introduced the first DSL Access Multiplexers (<a href="/wiki/DSLAM" title="DSLAM">DSLAM</a>), the large multi-modem systems used at the telephony offices, and later introduced customer ADSL modems under the Thomson brand. <a href="/wiki/Alcatel-Lucent" title="Alcatel-Lucent">Alcatel</a> remained the primary vendor of ADSL systems for well over a decade.<sup id="cite_ref-FOOTNOTECioffi201138_10-0" class="reference"><a href="#cite_note-FOOTNOTECioffi201138-10"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> </p><p>ADSL quickly replaced ISDN as the customer-facing solution for last-mile connectivity. ISDN has largely disappeared on the customer side, remaining in use only in niche roles like dedicated teleconferencing systems and similar legacy systems. </p> <div class="mw-heading mw-heading2"><h2 id="Design">Design</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=6" title="Edit section: Design"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><i>Integrated services</i> refers to ISDN's ability to deliver at minimum two simultaneous connections, in any combination of data, voice, <a href="/wiki/Videotelephony" title="Videotelephony">video</a>, and <a href="/wiki/Fax" title="Fax">fax</a>, over a <a href="/wiki/Local_loop" title="Local loop">single line</a>. Multiple devices can be attached to the line, and used as needed. That means an ISDN line can take care of what were expected to be most people's complete communications needs (apart from <a href="/wiki/Broadband_Internet_access" class="mw-redirect" title="Broadband Internet access">broadband Internet access</a> and entertainment <a href="/wiki/Television" title="Television">television</a>) at a much higher transmission rate, without forcing the purchase of multiple analog phone lines. It also refers to integrated switching and transmission<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> in that <a href="/wiki/Telephone_switch" class="mw-redirect" title="Telephone switch">telephone switching</a> and <a href="/wiki/Carrier_wave" title="Carrier wave">carrier wave</a> transmission are integrated rather than separate as in earlier technology. </p> <div class="mw-heading mw-heading3"><h3 id="Configurations">Configurations</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=7" title="Edit section: Configurations"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In ISDN, there are two types of channels, <i>B</i> (for "bearer") and <i>D</i> (for "data"). <i>B channels</i> are used for data (which may include voice), and <i>D channels</i> are intended for signaling and control (but can also be used for data). </p><p>There are two ISDN implementations. Basic Rate Interface (BRI), also called basic rate access (BRA) — consists of two B channels, each with bandwidth of 64 <a href="/wiki/Kbit/s" class="mw-redirect" title="Kbit/s">kbit/s</a>, and one D channel with a bandwidth of 16 kbit/s. Together these three channels can be designated as 2B+D. Primary Rate Interface (PRI), also called primary rate access (PRA) in Europe — contains a greater number of B channels and a D channel with a bandwidth of 64 kbit/s. The number of B channels for PRI varies according to the nation: in North America and Japan it is 23B+1D, with an aggregate bit rate of 1.544 <a href="/wiki/Mbit/s" class="mw-redirect" title="Mbit/s">Mbit/s</a> (<a href="/wiki/Digital_Signal_1" title="Digital Signal 1">T1</a>); in Europe, India and Australia it is 30B+2D, with an aggregate bit rate of 2.048 Mbit/s (<a href="/wiki/E-carrier" title="E-carrier">E1</a>). <a href="/wiki/Broadband_Integrated_Services_Digital_Network" title="Broadband Integrated Services Digital Network">Broadband Integrated Services Digital Network</a> (BISDN) is another ISDN implementation and it is able to manage different types of services at the same time. It is primarily used within <a href="/wiki/Network_backbone" class="mw-redirect" title="Network backbone">network backbones</a> and employs <a href="/wiki/Asynchronous_Transfer_Mode" title="Asynchronous Transfer Mode">ATM</a>. </p><p>Another alternative ISDN configuration can be used in which the B channels of an ISDN BRI line are <a href="/wiki/Channel_bonding" class="mw-redirect" title="Channel bonding">bonded</a> to provide a total duplex bandwidth of 128 kbit/s. This precludes use of the line for voice calls while the internet connection is in use. The B channels of several BRIs can be bonded, a typical use is a 384K videoconferencing channel. </p><p>Using <a href="/wiki/B8ZS" class="mw-redirect" title="B8ZS">bipolar with eight-zero substitution</a> encoding technique, call data is transmitted over the data (B) channels, with the signaling (D) channels used for call setup and management. Once a call is set up, there is a simple 64 kbit/s synchronous bidirectional data channel (actually implemented as two simplex channels, one in each direction) between the end parties, lasting until the call is terminated. There can be as many calls as there are bearer channels, to the same or different end-points. Bearer channels may also be <a href="/wiki/Multiplexing" title="Multiplexing">multiplexed</a> into what may be considered single, higher-bandwidth channels via a process called B channel BONDING, or via use of Multi-Link PPP "bundling" or by using an H0, H11, or H12 channel on a PRI. </p><p>The D channel can also be used for sending and receiving <a href="/wiki/X.25" title="X.25">X.25</a> data packets, and connection to X.25 packet network, this is specified in <a href="/w/index.php?title=X.31&action=edit&redlink=1" class="new" title="X.31 (page does not exist)">X.31</a>. In practice, X.31 was only commercially implemented in the UK, France, Japan and Germany. </p> <div class="mw-heading mw-heading3"><h3 id="Reference_points">Reference points</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=8" title="Edit section: Reference points"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A set of <i>reference points</i> are defined in the <a class="mw-selflink selflink">ISDN</a> <a href="/wiki/International_standard" title="International standard">standard</a> to refer to certain points between the <a href="/wiki/Telephone_company" class="mw-redirect" title="Telephone company">telco</a> and the end-user equipment. </p> <ul><li><a href="/wiki/R_interface" title="R interface">R</a> – defines the point between non-ISDN terminal equipment, <i>terminal equipment 2</i> (<i>TE2</i>), and a <i><a href="/wiki/Terminal_adapter" title="Terminal adapter">terminal adapter</a></i> (TA) which provides translation to and from such a device</li> <li><a href="/wiki/S_interface" title="S interface">S</a> – defines the point between ISDN terminal equipment, <i>terminal equipment 1</i> (<i>TE1</i>), or a TA and a <i>Network Termination Type 2</i> (<a href="/w/index.php?title=Network_termination_2&action=edit&redlink=1" class="new" title="Network termination 2 (page does not exist)">NT2</a>) device</li> <li><a href="/wiki/T-interface" class="mw-redirect" title="T-interface">T</a> – defines the point between the NT2 and <a href="/wiki/Network_termination_1" title="Network termination 1">network termination 1</a> (NT1) devices.</li></ul> <p>Most NT-1 devices can perform the functions of the NT2 as well, and so the S and T reference points are generally collapsed into the S/T reference point. </p><p>In North America, the NT1 device is considered <a href="/wiki/Customer_premises_equipment" class="mw-redirect" title="Customer premises equipment">customer premises equipment</a> (CPE) and must be maintained by the customer, thus, the U interface is provided to the customer. In other locations, the NT1 device is maintained by the telco, and the S/T interface is provided to the customer. In India, service providers provide U interface and an NT1 may be supplied by Service provider as part of service offering. </p> <div class="mw-heading mw-heading3"><h3 id="Basic_Rate_Interface">Basic Rate Interface</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=9" title="Edit section: Basic Rate Interface"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:ISDN_box_on_wall_June_21.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/66/ISDN_box_on_wall_June_21.jpg/220px-ISDN_box_on_wall_June_21.jpg" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/66/ISDN_box_on_wall_June_21.jpg/330px-ISDN_box_on_wall_June_21.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/66/ISDN_box_on_wall_June_21.jpg/440px-ISDN_box_on_wall_June_21.jpg 2x" data-file-width="4032" data-file-height="3024" /></a><figcaption>A decommissioned BT ISDN 2e box</figcaption></figure> <p>The entry level interface to ISDN is the <a href="/wiki/Basic_Rate_Interface" title="Basic Rate Interface">Basic Rate Interface</a> (BRI), a 128 <a href="/wiki/Kilobits_per_second" class="mw-redirect" title="Kilobits per second">kbit/s</a> service delivered over a pair of standard telephone copper wires.<sup id="cite_ref-Talkers_2013-03-28_12-0" class="reference"><a href="#cite_note-Talkers_2013-03-28-12"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> The 144 kbit/s overall payload rate is divided into two 64 kbit/s <a href="/wiki/Bearer_channel" title="Bearer channel">bearer channels</a> (<a href="/wiki/B_channel" title="B channel">'B' channels</a>) and one 16 kbit/s signaling channel (<a href="/wiki/D_channel" title="D channel">'D' channel</a> or data channel). This is sometimes referred to as 2B+D.<sup id="cite_ref-SW_Bell_ISDN_13-0" class="reference"><a href="#cite_note-SW_Bell_ISDN-13"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> </p><p>The interface specifies the following network interfaces: </p> <ul><li>The <i><a href="/wiki/U_interface" title="U interface">U interface</a></i> is a two-wire interface between the exchange and a <i>network terminating unit</i>, which is usually the <a href="/wiki/Demarcation_point" title="Demarcation point">demarcation point</a> in non-North American networks.</li> <li>The <i><a href="/wiki/T_interface" title="T interface">T interface</a></i> is a serial interface between a computing device and a <i><a href="/wiki/Terminal_adapter" title="Terminal adapter">terminal adapter</a></i>, which is the digital equivalent of a modem.</li> <li>The <i><a href="/wiki/S_interface" title="S interface">S interface</a></i> is a four-wire bus that ISDN consumer devices plug into; the S & T reference points are commonly implemented as a single interface labeled 'S/T' on a <a href="/wiki/Network_termination_1" title="Network termination 1">Network termination 1</a> (NT1).</li> <li>The <i><a href="/wiki/R_interface" title="R interface">R interface</a></i> defines the point between a non-ISDN device and a terminal adapter (TA) which provides translation to and from such a device.</li></ul> <p>BRI-ISDN is very popular in Europe but is much less common in North America. It is also common in Japan — where it is known as INS64.<sup id="cite_ref-Wisegeek_BRI_14-0" class="reference"><a href="#cite_note-Wisegeek_BRI-14"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-ISDN_SwitchType_15-0" class="reference"><a href="#cite_note-ISDN_SwitchType-15"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Primary_Rate_Interface">Primary Rate Interface</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=10" title="Edit section: Primary Rate Interface"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The other ISDN access available is the <a href="/wiki/Primary_Rate_Interface" title="Primary Rate Interface">Primary Rate Interface</a> (PRI), which is carried over <a href="/wiki/T-carrier" title="T-carrier">T-carrier</a> (T1) with 24 time slots (channels) in North America, and over <a href="/wiki/E-carrier" title="E-carrier">E-carrier</a> (E1) with 32 channels in most other countries. Each channel provides transmission at a 64 kbit/s data rate. </p><p>With the E1 carrier, the available channels are divided into 30 bearer (<i>B</i>) channels, one data (<i>D</i>) channel, and one timing and alarm channel. This scheme is often referred to as 30B+2D.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p><p>In North America, PRI service is delivered via T1 carriers with only one data channel, often referred to as 23B+D, and a total data rate of 1544 kbit/s. <a href="/wiki/Non-Facility_Associated_Signalling" title="Non-Facility Associated Signalling">Non-Facility Associated Signalling</a> (NFAS) allows two or more PRI circuits to be controlled by a single <a href="/wiki/D_channel" title="D channel">D channel</a>, which is sometimes called <i>23B+D + n*24B</i>. D-channel backup allows for a second D channel in case the primary fails. NFAS is commonly used on a <a href="/wiki/Digital_Signal_3" title="Digital Signal 3">Digital Signal 3</a> (DS3/T3). </p><p>PRI-ISDN is popular throughout the world, especially for connecting <a href="/wiki/Private_branch_exchange" class="mw-redirect" title="Private branch exchange">private branch exchanges</a> to the <a href="/wiki/Public_switched_telephone_network" title="Public switched telephone network">public switched telephone network</a> (PSTN). </p><p>Even though many network professionals use the term <i>ISDN</i> to refer to the lower-bandwidth BRI circuit, in North America BRI is relatively uncommon whilst PRI circuits serving PBXs are commonplace. </p> <div class="mw-heading mw-heading3"><h3 id="Bearer_channel">Bearer channel</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=11" title="Edit section: Bearer channel"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The bearer channel (B) is a standard 64 kbit/s voice channel of 8 bits sampled at 8 kHz with <a href="/wiki/G.711" title="G.711">G.711</a> encoding. B-channels can also be used to carry data, since they are nothing more than digital channels. </p><p>Each one of these channels is known as a <a href="/wiki/DS0" class="mw-redirect" title="DS0">DS0</a>. </p><p>Most B channels can carry a 64<span class="nowrap"> </span>kbit/s signal, but some were limited to 56K because they traveled over <a href="/wiki/Robbed-bit_signaling" title="Robbed-bit signaling">RBS</a> lines. This was commonplace in the 20th century, but has since become less so. </p> <div class="mw-heading mw-heading3"><h3 id="X.25">X.25</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=12" title="Edit section: X.25"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/X.25" title="X.25">X.25</a> can be carried over the B or D channels of a BRI line, and over the B channels of a PRI line. X.25 over the D channel is used at many point-of-sale (credit card) terminals because it eliminates the modem setup, and because it connects to the central system over a B channel, thereby eliminating the need for modems and making much better use of the central system's telephone lines. </p><p><a href="/wiki/X.25" title="X.25">X.25</a> was also part of an ISDN protocol called "Always On/Dynamic ISDN", or AO/DI. This allowed a user to have a constant multi-link PPP connection to the internet over X.25 on the D channel, and brought up one or two B channels as needed. </p> <div class="mw-heading mw-heading3"><h3 id="Frame_Relay">Frame Relay</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=13" title="Edit section: Frame Relay"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In theory, <a href="/wiki/Frame_Relay" title="Frame Relay">Frame Relay</a> can operate over the D channel of BRIs and PRIs, but it is seldom, if ever, used. </p> <div class="mw-heading mw-heading2"><h2 id="Uses">Uses</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=14" title="Edit section: Uses"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Telephone_industry">Telephone industry</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=15" title="Edit section: Telephone industry"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>ISDN is a core technology in the telephone industry. A <a href="/wiki/Telephone_network" title="Telephone network">telephone network</a> can be thought of as a collection of wires strung between switching systems. The common electrical specification for the signals on these wires is <a href="/wiki/Digital_Signal_1" title="Digital Signal 1">T1</a> or <a href="/wiki/E-carrier" title="E-carrier">E1</a>. Between telephone company switches, the signaling is performed via <a href="/wiki/Signaling_System_No_7" class="mw-redirect" title="Signaling System No 7">SS7</a>. Normally, a PBX is connected via a T1 with <a href="/wiki/Robbed_bit_signaling" class="mw-redirect" title="Robbed bit signaling">robbed bit signaling</a> to indicate on-hook or off-hook conditions and <a href="/wiki/Multi-frequency" class="mw-redirect" title="Multi-frequency">MF</a> and <a href="/wiki/Dual-tone_multi-frequency" class="mw-redirect" title="Dual-tone multi-frequency">DTMF</a> tones to encode the destination number. ISDN is much better because messages can be sent much more quickly than by trying to encode numbers as long (100 <a href="/wiki/Millisecond" title="Millisecond">ms</a> per digit) tone sequences. This results in faster call setup times. Also, a greater number of features are available and fraud is reduced. </p><p>In common use, ISDN is often limited to usage to <a href="/wiki/Q.931" title="Q.931">Q.931</a> and related protocols, which are a set of <a href="/wiki/Signaling_(telecommunications)" title="Signaling (telecommunications)">signaling protocols</a> establishing and breaking circuit-switched connections, and for advanced <a href="/wiki/Calling_feature" class="mw-redirect" title="Calling feature">calling features</a> for the user.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> Another usage was the deployment of <a href="/wiki/Videoconference" class="mw-redirect" title="Videoconference">videoconference</a> systems, where a direct end-to-end connection is desirable. ISDN uses the <a href="/wiki/H.320" title="H.320">H.320</a> standard for <a href="/wiki/Audio_coding" class="mw-redirect" title="Audio coding">audio coding</a> and <a href="/wiki/Video_coding" class="mw-redirect" title="Video coding">video coding</a>. </p><p>ISDN is also used as a smart-network technology intended to add new services to the <a href="/wiki/Public_switched_telephone_network" title="Public switched telephone network">public switched telephone network</a> (PSTN) by giving users direct access to end-to-end circuit-switched digital services and as a backup or failsafe circuit solution for critical use data circuits. </p> <div class="mw-heading mw-heading3"><h3 id="Video_conferencing">Video conferencing</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=16" title="Edit section: Video conferencing"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>One of ISDNs successful use-cases was in the <a href="/wiki/Videoconference" class="mw-redirect" title="Videoconference">videoconference</a> field, where even small improvements in data rates are useful, but more importantly, its direct end-to-end connection offers lower latency and better reliability than packet-switched networks of the 1990s. The <a href="/wiki/H.320" title="H.320">H.320</a> standard for <a href="/wiki/Audio_coding" class="mw-redirect" title="Audio coding">audio coding</a> and <a href="/wiki/Video_coding" class="mw-redirect" title="Video coding">video coding</a> was designed with ISDN in mind, and more specifically its 64 kbit/s basic data rate. including <a href="/wiki/Audio_codecs" class="mw-redirect" title="Audio codecs">audio codecs</a> such as <a href="/wiki/G.711" title="G.711">G.711</a> (<a href="/wiki/Pulse-code_modulation" title="Pulse-code modulation">PCM</a>) and <a href="/wiki/G.728" title="G.728">G.728</a> (<a href="/wiki/CELP" class="mw-redirect" title="CELP">CELP</a>), and <a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">discrete cosine transform</a> (DCT) <a href="/wiki/Video_codecs" class="mw-redirect" title="Video codecs">video codecs</a> such as <a href="/wiki/H.261" title="H.261">H.261</a> and <a href="/wiki/H.263" title="H.263">H.263</a>.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Broadcast_industry">Broadcast industry</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=17" title="Edit section: Broadcast industry"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>ISDN is used heavily by the broadcast industry as a reliable way of switching low-latency, high-quality, long-distance audio circuits. In conjunction with an appropriate <a href="/wiki/Codec" title="Codec">codec</a> using MPEG or various manufacturers' proprietary algorithms, an ISDN BRI can be used to send stereo bi-directional audio coded at 128 kbit/s with 20 Hz – 20 kHz audio bandwidth, although commonly the <a href="/wiki/G.722" title="G.722">G.722</a> algorithm is used with a single 64 kbit/s B channel to send much lower latency mono audio at the expense of audio quality. Where very high quality audio is required multiple ISDN BRIs can be used in parallel to provide a higher bandwidth circuit switched connection. <a href="/wiki/BBC_Radio_3" title="BBC Radio 3">BBC Radio 3</a> commonly makes use of three ISDN BRIs to carry 320 kbit/s audio stream for live outside broadcasts. ISDN BRI services are used to link remote studios, sports grounds and <a href="/wiki/Remote_broadcast" title="Remote broadcast">outside broadcasts</a> into the main <a href="/wiki/Recording_studio" title="Recording studio">broadcast studio</a>. ISDN via satellite is used by field reporters around the world. It is also common to use ISDN for the return audio links to remote satellite broadcast vehicles. </p><p>In many countries, such as the UK and Australia, ISDN has displaced the older technology of equalised analogue landlines, with these circuits being phased out by telecommunications providers. Use of IP-based streaming codecs such as <a href="/wiki/Comrex" title="Comrex">Comrex</a> ACCESS and <a href="/wiki/IpDTL" title="IpDTL">ipDTL</a> is becoming more widespread in the broadcast sector, using broadband internet to connect remote studios.<sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Backup_lines">Backup lines</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=18" title="Edit section: Backup lines"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Providing a backup line for business's inter-office and internet connectivity was a popular use of the technology.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="International_deployment">International deployment</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=19" title="Edit section: International deployment"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A study<sup id="cite_ref-22" class="reference"><a href="#cite_note-22"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> of the Germany's Federal Ministry of Education and Research shows the following share of ISDN-channels per 1,000 inhabitants in 2005: </p> <ul><li><a href="/wiki/Norway" title="Norway">Norway</a> 401</li> <li><a href="/wiki/Denmark" title="Denmark">Denmark</a> 339</li> <li><a href="/wiki/Germany" title="Germany">Germany</a> 333</li> <li><a href="/wiki/Switzerland" title="Switzerland">Switzerland</a> 331</li> <li><a href="/wiki/Japan" title="Japan">Japan</a> 240</li> <li><a href="/wiki/United_Kingdom" title="United Kingdom">United Kingdom</a> 160</li> <li><a href="/wiki/Finland" title="Finland">Finland</a> 160</li> <li><a href="/wiki/Sweden" title="Sweden">Sweden</a> 135</li> <li><a href="/wiki/Italy" title="Italy">Italy</a> 105</li> <li><a href="/wiki/France" title="France">France</a> 85</li> <li><a href="/wiki/Spain" title="Spain">Spain</a> 58</li> <li><a href="/wiki/United_States" title="United States">United States</a> 47</li></ul> <div class="mw-heading mw-heading3"><h3 id="Australia">Australia</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=20" title="Edit section: Australia"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/Telstra" title="Telstra">Telstra</a> provides the business customer with the ISDN services. There are five types of ISDN services which are ISDN2, ISDN2 Enhanced, ISDN10, ISDN20 and ISDN30. Telstra changed the minimum monthly charge for voice and data calls. In general, there are two group of ISDN service types; The Basic Rate services – ISDN 2 or ISDN 2 Enhanced. Another group of types are the Primary Rate services, ISDN 10/20/30.<sup id="cite_ref-Telstra-2018_23-0" class="reference"><a href="#cite_note-Telstra-2018-23"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> Telstra announced that the new sales of ISDN product would be unavailable as of 31 January 2018. The final exit date of ISDN service and migration to the new service would be confirmed by 2022.<sup id="cite_ref-Telstra-2022_24-0" class="reference"><a href="#cite_note-Telstra-2022-24"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="France">France</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=21" title="Edit section: France"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/Orange_S.A." title="Orange S.A.">Orange</a> offers ISDN services under their product name Numeris (2 B+D), of which a professional Duo and home Itoo version is available. ISDN is generally known as RNIS in France and has widespread availability. The introduction of ADSL is reducing ISDN use<sup class="noprint Inline-Template" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Manual_of_Style/Dates_and_numbers#Chronological_items" title="Wikipedia:Manual of Style/Dates and numbers"><span title="The time period mentioned near this tag is ambiguous. (April 2013)">when?</span></a></i>]</sup> for data transfer and Internet access, although it is still common in more rural and outlying areas, and for applications such as <a href="/wiki/Private_branch_exchange" class="mw-redirect" title="Private branch exchange">business voice</a> and <a href="/wiki/Point_of_sale" title="Point of sale">point-of-sale terminals</a>. In 2023, Numeris services will enter a phase-out process. They will be replaced by VoIP services. </p> <div class="mw-heading mw-heading3"><h3 id="Germany">Germany</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=22" title="Edit section: Germany"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:DBP_1988_1368_ISDN.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f9/DBP_1988_1368_ISDN.jpg/220px-DBP_1988_1368_ISDN.jpg" decoding="async" width="220" height="138" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f9/DBP_1988_1368_ISDN.jpg/330px-DBP_1988_1368_ISDN.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f9/DBP_1988_1368_ISDN.jpg/440px-DBP_1988_1368_ISDN.jpg 2x" data-file-width="1070" data-file-height="670" /></a><figcaption>German stamp</figcaption></figure> <p>In <a href="/wiki/Germany" title="Germany">Germany</a>, ISDN was very popular with an installed base of 25 million channels (29% of all subscriber lines in Germany as of 2003 and 20% of all ISDN channels worldwide). Due to the success of ISDN, the number of installed analog lines was decreasing. <a href="/wiki/Deutsche_Telekom" title="Deutsche Telekom">Deutsche Telekom</a> (DTAG) offered both BRI and PRI. Competing phone companies often offered ISDN only and no analog lines. However, these operators generally offered free hardware that also allows the use of POTS equipment, such as NTBAs ("<a href="https://de.wikipedia.org/wiki/Network_Termination_for_ISDN_Basic_rate_Access" class="extiw" title="de:Network Termination for ISDN Basic rate Access">Network Termination for ISDN Basic rate Access</a>": small devices that bridge the two-wire UK0 line to the four-wire S0 bus) with integrated <a href="/wiki/Terminal_adapter" title="Terminal adapter">terminal adapters</a>. Because of the widespread availability of ADSL services, ISDN was primarily used for voice and fax traffic. </p><p>Until 2007 ISDN (BRI) and <a href="/wiki/ADSL" title="ADSL">ADSL</a>/<a href="/wiki/VDSL" title="VDSL">VDSL</a> were often bundled on the same line, mainly because the combination of DSL with an analog line had no cost advantage over a combined ISDN-DSL line. This practice turned into an issue for the operators when vendors of ISDN technology stopped manufacturing it and spare parts became hard to come by. Since then phone companies started introducing cheaper xDSL-only products using <a href="/wiki/VoIP" class="mw-redirect" title="VoIP">VoIP</a> for telephony,<sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> also in an effort to reduce their costs by operating separate data & voice networks. </p><p>Since approximately 2010, most German operators have offered more and more VoIP on top of DSL lines and ceased offering ISDN lines. New ISDN lines have been no longer available in Germany since 2018, existing ISDN lines were phased out from 2016 onwards and existing customers were encouraged to move to DSL-based VoIP products. Deutsche Telekom intended to phase-out by 2018<sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> but postponed the date to 2020, other providers like Vodafone estimate to have their phase-out completed by 2022. </p> <div class="mw-heading mw-heading3"><h3 id="Greece">Greece</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=23" title="Edit section: Greece"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/OTE" title="OTE">OTE</a>, the incumbent telecommunications operator, offers ISDN BRI (BRA) services in <a href="/wiki/Greece" title="Greece">Greece</a>. Following the launch of ADSL in 2003, the importance of ISDN for data transfer began to decrease and is today limited to niche business applications with point-to-point requirements. </p> <div class="mw-heading mw-heading3"><h3 id="India">India</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=24" title="Edit section: India"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/Bharat_Sanchar_Nigam_Limited" title="Bharat Sanchar Nigam Limited">Bharat Sanchar Nigam Limited</a>, <a href="/wiki/Reliance_Communications" title="Reliance Communications">Reliance Communications</a> and <a href="/wiki/Bharti_Airtel" title="Bharti Airtel">Bharti Airtel</a> are the largest communication service providers, and offer both ISDN BRI and PRI services across the country. Reliance Communications and Bharti Airtel uses the DLC technology for providing these services. With the introduction of broadband technology, the load on bandwidth is being absorbed by ADSL. ISDN continues to be an important backup network for point-to-point leased line customers such as banks, e-Seva Centers,<sup id="cite_ref-27" class="reference"><a href="#cite_note-27"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Life_Insurance_Corporation_of_India" class="mw-redirect" title="Life Insurance Corporation of India">Life Insurance Corporation of India</a>, and <a href="/wiki/State_Bank_of_India" title="State Bank of India">SBI</a> ATMs. </p> <div class="mw-heading mw-heading3"><h3 id="Japan">Japan</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=25" title="Edit section: Japan"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>On April 19, 1988, Japanese telecommunications company <a href="/wiki/Nippon_Telegraph_and_Telephone" title="Nippon Telegraph and Telephone">NTT</a> began offering nationwide ISDN services trademarked INS Net 64, and INS Net 1500, a fruition of NTT's independent research and trial from the 1970s of what it referred to the INS (Information Network System).<sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> </p><p>Previously, in April 1985, Japanese digital telephone exchange hardware made by Fujitsu was used to experimentally deploy the world's first I interface ISDN. The I interface, unlike the older and incompatible Y interface, is what modern ISDN services use today. </p><p>Since 2000, NTT's ISDN offering have been known as <a href="https://ja.wikipedia.org/wiki/%E3%83%95%E3%83%AC%E3%83%83%E3%83%84" class="extiw" title="ja:フレッツ">FLET's</a> ISDN, incorporating the "FLET's" brand that NTT uses for all of its ISP offerings. </p><p>In Japan, the number of ISDN subscribers dwindled as alternative technologies such as <a href="/wiki/ADSL" title="ADSL">ADSL</a>, <a href="/wiki/Cable_Internet_access" title="Cable Internet access">cable Internet access</a>, and <a href="/wiki/Fiber_to_the_home" class="mw-redirect" title="Fiber to the home">fiber to the home</a> gained greater popularity. On November 2, 2010, NTT announced plans to migrate their backend from <a href="/wiki/PSTN" class="mw-redirect" title="PSTN">PSTN</a> to the <a href="/wiki/IP_network" class="mw-redirect" title="IP network">IP network</a> from around 2020 to around 2025. For this migration, ISDN services will be retired, and fiber optic services are recommended as an alternative.<sup id="cite_ref-29" class="reference"><a href="#cite_note-29"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Norway">Norway</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=26" title="Edit section: Norway"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>On April 19, 1988, Norwegian telecommunications company <a href="/wiki/Telenor" title="Telenor">Telenor</a> began offering nationwide ISDN services trademarked INS Net 64, and INS Net 1500, a fruition of NTT's independent research and trial from the 1970s of what it referred to the INS (Information Network System).<sup id="cite_ref-30" class="reference"><a href="#cite_note-30"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="United_Kingdom">United Kingdom</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=27" title="Edit section: United Kingdom"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In the <a href="/wiki/United_Kingdom" title="United Kingdom">United Kingdom</a>, <a href="/wiki/BT_Group" title="BT Group">British Telecom</a> (BT) provides ISDN2e (BRI) as well as ISDN30 (PRI). Until April 2006, they also offered services named <a href="/wiki/BT_Highway" title="BT Highway">Home Highway and Business Highway</a>, which were BRI ISDN-based services that offered integrated analogue connectivity as well as ISDN. Later versions of the Highway products also included built-in <a href="/wiki/USB" title="USB">USB</a> sockets for direct computer access. Home Highway was bought by many home users, usually for Internet connection, although not as fast as ADSL, because it was available before ADSL and in places where ADSL does not reach. </p><p>In early 2015, BT announced their intention to retire the UK's ISDN infrastructure by 2025.<sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="United_States_and_Canada">United States and Canada</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=28" title="Edit section: United States and Canada"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>ISDN-BRI never gained popularity as a general use telephone access technology in Canada and the US, and remains a niche product. The service was seen as "a solution in search of a problem",<sup id="cite_ref-32" class="reference"><a href="#cite_note-32"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup> and the extensive array of options and features were difficult for customers to understand and use. ISDN has long been known by derogatory <a href="/wiki/Backronym" title="Backronym">backronyms</a> highlighting these issues, such as <i>It Still Does Nothing</i>, <i>Innovations Subscribers Don't Need</i>, and <i>I Still Don't kNow</i>,<sup id="cite_ref-33" class="reference"><a href="#cite_note-33"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-34" class="reference"><a href="#cite_note-34"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup> or, from the supposed standpoint of telephone companies, <i>I Smell Dollars Now</i>.<sup id="cite_ref-35" class="reference"><a href="#cite_note-35"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup> </p><p>Although various minimum bandwidths have been used in definitions of <a href="/wiki/Broadband_Internet_access" class="mw-redirect" title="Broadband Internet access">Broadband Internet access</a>, ranging up from 64 kbit/s up to 1.0 Mbit/s, the 2006 OECD report is typical by defining broadband as having download data transfer rates equal to or faster than 256 kbit/s,<sup id="cite_ref-36" class="reference"><a href="#cite_note-36"><span class="cite-bracket">[</span>35<span class="cite-bracket">]</span></a></sup> while the United States FCC, as of 2008, defines broadband as anything above 768 kbit/s.<sup id="cite_ref-37" class="reference"><a href="#cite_note-37"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Engadget_38-0" class="reference"><a href="#cite_note-Engadget-38"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup> Once the term "broadband" came to be associated with data rates incoming to the customer at 256 kbit/s or more, and alternatives like <a href="/wiki/ADSL" title="ADSL">ADSL</a> grew in popularity, the consumer market for BRI did not develop. Its only remaining advantage is that, while ADSL has a functional distance limitation and can use <a href="/wiki/ADSL_loop_extender" title="ADSL loop extender">ADSL loop extenders</a>, BRI has a greater limit and can use repeaters. As such, BRI may be acceptable for customers who are too remote for ADSL. Widespread use of BRI is further stymied by some small North American <a href="/wiki/Competitive_local_exchange_carrier" title="Competitive local exchange carrier">CLECs</a> such as <a href="/wiki/CenturyTel" class="mw-redirect" title="CenturyTel">CenturyTel</a> having given up on it and not providing Internet access using it.<sup id="cite_ref-39" class="reference"><a href="#cite_note-39"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup> However, AT&T in most states (especially the former SBC/SWB territory) will still install an ISDN BRI line anywhere a normal analog line can be placed and the monthly charge is roughly $55.<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. (August 2020)">citation needed</span></a></i>]</sup> </p><p>ISDN-BRI is currently primarily used in industries with specialized and very specific needs. High-end <a href="/wiki/Videoconferencing" class="mw-redirect" title="Videoconferencing">videoconferencing</a> hardware can bond up to 8 B-channels together (using a BRI circuit for every 2 channels) to provide digital, circuit-switched video connections to almost anywhere in the world. This is very expensive, and is being replaced by IP-based conferencing, but where cost concern is less of an issue than predictable quality and where a <a href="/wiki/Quality_of_service" title="Quality of service">QoS</a>-enabled IP does not exist, BRI is the preferred choice. </p><p>Most modern non-<a href="/wiki/VoIP" class="mw-redirect" title="VoIP">VoIP</a> PBXs use ISDN-PRI circuits. These are connected via <a href="/wiki/T-carrier" title="T-carrier">T1 lines</a> with the central office switch, replacing older analog two-way and <a href="/wiki/Direct_inward_dialing" class="mw-redirect" title="Direct inward dialing">direct inward dialing</a> (DID) trunks. PRI is capable of delivering <a href="/wiki/Calling_Line_Identification" class="mw-redirect" title="Calling Line Identification">Calling Line Identification</a> (CLID) in both directions so that the telephone number of an extension, rather than a company's main number, can be sent. It is still commonly used in <a href="/wiki/Recording_studio" title="Recording studio">recording studios</a> and some <a href="/wiki/Radio_program" title="Radio program">radio programs</a>, when a <a href="/wiki/Voice-over" title="Voice-over">voice-over</a> actor or host is in one studio conducting <a href="/wiki/Remote_work" title="Remote work">remote work</a>, but the director and producer are in a studio at another location.<sup id="cite_ref-Talkers_2013-03-28_12-1" class="reference"><a href="#cite_note-Talkers_2013-03-28-12"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> The ISDN protocol delivers channelized, not-over-the-Internet service, powerful call setup and routing features, faster setup and tear down, superior audio fidelity as compared to <a href="/wiki/Plain_old_telephone_service" title="Plain old telephone service">plain old telephone service</a> (POTS), lower delay and, at higher densities, lower cost. </p><p>In 2013, <a href="/wiki/Verizon" title="Verizon">Verizon</a> announced it would no longer take orders for ISDN service in the <a href="/wiki/Northeastern_United_States" title="Northeastern United States">Northeastern United States</a>.<sup id="cite_ref-Talkers_2013-03-28_12-2" class="reference"><a href="#cite_note-Talkers_2013-03-28-12"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></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=ISDN&action=edit&section=29" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/ISDN_User_Part" title="ISDN User Part">ISDN User Part</a></li> <li><a href="/wiki/Common_ISDN_Application_Programming_Interface" title="Common ISDN Application Programming Interface">Common ISDN Application Programming Interface</a></li> <li><a href="/wiki/Asynchronous_Transfer_Mode" title="Asynchronous Transfer Mode">Asynchronous Transfer Mode</a></li> <li><a href="/wiki/B-ISDN" class="mw-redirect" title="B-ISDN">B-ISDN</a></li> <li><a href="/wiki/ETSI" class="mw-redirect" title="ETSI">ETSI</a></li> <li><a href="/wiki/List_of_device_bandwidths" class="mw-redirect" title="List of device bandwidths">List of device bandwidths</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=30" title="Edit section: Notes"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-lower-alpha"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text">There is not a single ISDN specification, but mere a collection of various incompatible dialects.</span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=31" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239543626"><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</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 id="CITEREFDr._rer._nat._Peter_Bocker1988" class="citation book cs1">Dr. rer. nat. Peter Bocker (1988). <i>ISDN The Integrated Services Digital Network: Concepts, Methods, Systems</i>. Springer Berlin Heidelberg. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-662-08036-8" title="Special:BookSources/978-3-662-08036-8"><bdi>978-3-662-08036-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=ISDN+The+Integrated+Services+Digital+Network%3A+Concepts%2C+Methods%2C+Systems.&rft.pub=Springer+Berlin+Heidelberg&rft.date=1988&rft.isbn=978-3-662-08036-8&rft.au=Dr.+rer.+nat.+Peter+Bocker&rfr_id=info%3Asid%2Fen.wikipedia.org%3AISDN" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDecinaScace1986" class="citation journal cs1">Decina, M; Scace, E (May 1986). "CCITT Recommendations on the ISDN: A Review". <i>IEEE Journal on Selected Areas in Communications</i>. <b>4</b> (3): 320–25. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FJSAC.1986.1146333">10.1109/JSAC.1986.1146333</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0733-8716">0733-8716</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=IEEE+Journal+on+Selected+Areas+in+Communications&rft.atitle=CCITT+Recommendations+on+the+ISDN%3A+A+Review&rft.volume=4&rft.issue=3&rft.pages=320-25&rft.date=1986-05&rft_id=info%3Adoi%2F10.1109%2FJSAC.1986.1146333&rft.issn=0733-8716&rft.aulast=Decina&rft.aufirst=M&rft.au=Scace%2C+E&rfr_id=info%3Asid%2Fen.wikipedia.org%3AISDN" class="Z3988"></span></span> </li> <li id="cite_note-FOOTNOTECioffi201130-4"><span class="mw-cite-backlink">^ <a href="#cite_ref-FOOTNOTECioffi201130_4-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-FOOTNOTECioffi201130_4-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-FOOTNOTECioffi201130_4-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><a href="#CITEREFCioffi2011">Cioffi 2011</a>, p. 30.</span> </li> <li id="cite_note-FOOTNOTECioffi201131-5"><span class="mw-cite-backlink">^ <a href="#cite_ref-FOOTNOTECioffi201131_5-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-FOOTNOTECioffi201131_5-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-FOOTNOTECioffi201131_5-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-FOOTNOTECioffi201131_5-3"><sup><i><b>d</b></i></sup></a> <a href="#cite_ref-FOOTNOTECioffi201131_5-4"><sup><i><b>e</b></i></sup></a> <a href="#cite_ref-FOOTNOTECioffi201131_5-5"><sup><i><b>f</b></i></sup></a></span> <span class="reference-text"><a href="#CITEREFCioffi2011">Cioffi 2011</a>, p. 31.</span> </li> <li id="cite_note-FOOTNOTECioffi201132-6"><span class="mw-cite-backlink">^ <a href="#cite_ref-FOOTNOTECioffi201132_6-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-FOOTNOTECioffi201132_6-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><a href="#CITEREFCioffi2011">Cioffi 2011</a>, p. 32.</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="CITEREFSchulte-Braucks1989" class="citation journal cs1">Schulte-Braucks, Reinhard (1989). <a rel="nofollow" class="external text" href="https://ir.lawnet.fordham.edu/ilj/vol13/iss2/5">"Telecommunications Law and Policy in the European Community"</a>. <i><a href="/wiki/Fordham_International_Law_Journal" title="Fordham International Law Journal">Fordham Int'l L.J.</a></i> <b>13</b> (2): 234<span class="reference-accessdate">. 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Retrieved <span class="nowrap">April 6,</span> 2013</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=What+Is+Basic+Rate+Interface%3F&rft_id=http%3A%2F%2Fwww.wisegeek.com%2Fwhat-is-basic-rate-interface.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AISDN" class="Z3988"></span></span> </li> <li id="cite_note-ISDN_SwitchType-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-ISDN_SwitchType_15-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://msdn.microsoft.com/en-us/library/windows/hardware/ff541725%28v=vs.85%29.aspx">"ISDN\SwitchType"</a>. Microsoft<span class="reference-accessdate">. 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Retrieved <span class="nowrap">7 November</span> 2019</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=EE+Times&rft.atitle=The+H.320+Recommendation+Overview&rft.date=1997-06-13&rft.aulast=Davis&rft.aufirst=Andrew&rft_id=https%3A%2F%2Fwww.eetimes.com%2Fdocument.asp%3Fdoc_id%3D1275886&rfr_id=info%3Asid%2Fen.wikipedia.org%3AISDN" class="Z3988"></span></span> </li> <li id="cite_note-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-19">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation book cs1"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=8vhEAQAAIAAJ"><i>IEEE WESCANEX 97: communications, power, and computing : conference proceedings</i></a>. University of Manitoba, Winnipeg, Manitoba, Canada: <a href="/wiki/Institute_of_Electrical_and_Electronics_Engineers" title="Institute of Electrical and Electronics Engineers">Institute of Electrical and Electronics Engineers</a>. May 22–23, 1997. p. 30. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780780341470" title="Special:BookSources/9780780341470"><bdi>9780780341470</bdi></a>. <q>H.263 is similar to, but more complex than H.261. 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McGraw-Hill Professional. p. 770. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-07-145222-9" title="Special:BookSources/978-0-07-145222-9"><bdi>978-0-07-145222-9</bdi></a><span class="reference-accessdate">. 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Retrieved <span class="nowrap">12 May</span> 2012</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Call+Center+Dictionary%3A+The+Complete+Guide+to+Call+Center+%26+Customer+Support+Technology+Solutions&rft.pages=227&rft.pub=Focal+Press&rft.date=2002-01-03&rft.isbn=978-1-57820-095-5&rft.aulast=Bodin&rft.aufirst=Madeline&rft.au=Dawson%2C+Keith&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DCTXhqkFDQKQC%26pg%3DPA101&rfr_id=info%3Asid%2Fen.wikipedia.org%3AISDN" class="Z3988"></span></span> </li> <li id="cite_note-35"><span class="mw-cite-backlink"><b><a href="#cite_ref-35">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=Idg9EcuKlT4C&dq=isdn+i+smell+dollars+now&pg=PA91">Telecompetition: The Free Market Road to the Information Highway</a>, Lawrence Gasman, p. 91</span> </li> <li id="cite_note-36"><span class="mw-cite-backlink"><b><a href="#cite_ref-36">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="http://www.oecd.org/document/7/0,3343,en_2649_34223_38446855_1_1_1_1,00.html"><i>Broadband Statistics</i></a> (report), OECD, 2006, <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110527044720/http://www.oecd.org/document/7/0,3343,en_2649_34223_38446855_1_1_1_1,00.html">archived</a> from the original on 2011-05-27<span class="reference-accessdate">, retrieved <span class="nowrap">2012-12-10</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Broadband+Statistics&rft.pub=OECD&rft.date=2006&rft_id=http%3A%2F%2Fwww.oecd.org%2Fdocument%2F7%2F0%2C3343%2Cen_2649_34223_38446855_1_1_1_1%2C00.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AISDN" class="Z3988"></span></span> </li> <li id="cite_note-37"><span class="mw-cite-backlink"><b><a href="#cite_ref-37">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMartin" class="citation cs2">Martin, Kevin J, <a rel="nofollow" class="external text" href="https://web.archive.org/web/20111017203347/http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-280909A2.doc"><i>Statement of Chairman</i></a>, <a href="/wiki/United_States_of_America" class="mw-redirect" title="United States of America">US</a>: FCC, archived from <a rel="nofollow" class="external text" href="https://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-280909A2.doc">the original</a> <span class="cs1-format">(<a href="/wiki/Microsoft" title="Microsoft">MS</a> <a href="/wiki/Microsoft_Word" title="Microsoft Word">Word</a> doc)</span> on 2011-10-17<span class="reference-accessdate">, retrieved <span class="nowrap">2012-12-10</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Statement+of+Chairman&rft.place=US&rft.pub=FCC&rft.aulast=Martin&rft.aufirst=Kevin+J&rft_id=http%3A%2F%2Fhraunfoss.fcc.gov%2Fedocs_public%2Fattachmatch%2FDOC-280909A2.doc&rfr_id=info%3Asid%2Fen.wikipedia.org%3AISDN" class="Z3988"></span>.</span> </li> <li id="cite_note-Engadget-38"><span class="mw-cite-backlink"><b><a href="#cite_ref-Engadget_38-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="https://www.engadget.com/2008/03/19/fcc-redefines-broadband-to-mean-768kbps-fast-to-mean-kinda/">"FCC redefines "broadband" to mean 768 kbit/s, "fast" to mean "kinda slow"<span class="cs1-kern-right"></span>"</a>, <i>Engadget</i>, 2008-03-19, <a rel="nofollow" class="external text" href="https://web.archive.org/web/20210606030829/https://www.engadget.com/2008-03-19-fcc-redefines-broadband-to-mean-768kbps-fast-to-mean-kinda.html">archived</a> from the original on 2021-06-06<span class="reference-accessdate">, retrieved <span class="nowrap">2017-09-01</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Engadget&rft.atitle=FCC+redefines+%22broadband%22+to+mean+768+kbit%2Fs%2C+%22fast%22+to+mean+%22kinda+slow%22&rft.date=2008-03-19&rft_id=https%3A%2F%2Fwww.engadget.com%2F2008%2F03%2F19%2Ffcc-redefines-broadband-to-mean-768kbps-fast-to-mean-kinda%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AISDN" class="Z3988"></span>.</span> </li> <li id="cite_note-39"><span class="mw-cite-backlink"><b><a href="#cite_ref-39">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2">"Disclaimer", <a rel="nofollow" class="external text" href="https://web.archive.org/web/20081225063242/http://www.centurytel.com/Pages/Disclaimers/internetDisclaimer.jsp"><i>Internet Access service offerings</i></a>, CenturyTel, archived from <a rel="nofollow" class="external text" href="http://www.centurytel.com/Pages/Disclaimers/internetDisclaimer.jsp">the original</a> on 2008-12-25<span class="reference-accessdate">, retrieved <span class="nowrap">2009-06-07</span></span>, <q>You may not obtain Internet services over ISDN lines (BRI or PRI), dedicated circuits or special service circuits</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Disclaimer&rft.btitle=Internet+Access+service+offerings&rft.pub=CenturyTel&rft_id=http%3A%2F%2Fwww.centurytel.com%2FPages%2FDisclaimers%2FinternetDisclaimer.jsp&rfr_id=info%3Asid%2Fen.wikipedia.org%3AISDN" class="Z3988"></span>.</span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=ISDN&action=edit&section=32" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style data-mw-deduplicate="TemplateStyles:r1237033735">@media print{body.ns-0 .mw-parser-output .sistersitebox{display:none!important}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}</style><div class="side-box side-box-right plainlinks sistersitebox"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style> <div class="side-box-flex"> <div class="side-box-image"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/d/df/Wikibooks-logo-en-noslogan.svg/40px-Wikibooks-logo-en-noslogan.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/df/Wikibooks-logo-en-noslogan.svg/60px-Wikibooks-logo-en-noslogan.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/df/Wikibooks-logo-en-noslogan.svg/80px-Wikibooks-logo-en-noslogan.svg.png 2x" data-file-width="400" data-file-height="400" /></span></span></div> <div class="side-box-text plainlist">Wikibooks has a book on the topic of: <i><b><a href="https://en.wikibooks.org/wiki/Nets,_Webs_and_the_Information_Infrastructure" class="extiw" title="wikibooks:Nets, Webs and the Information Infrastructure">Nets, Webs and the Information Infrastructure</a></b></i></div></div> </div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCioffi2011" class="citation journal cs1">Cioffi, John (May 2011). <a rel="nofollow" class="external text" href="https://ieeexplore.ieee.org/document/5762795">"Lighting up copper"</a>. <i>IEEE Communications Magazine</i>. <b>49</b> (5): 30–43. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FMCOM.2011.5762795">10.1109/MCOM.2011.5762795</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:8661205">8661205</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20210501174535/https://ieeexplore.ieee.org/document/5762795/">Archived</a> from the original on 2021-05-01<span class="reference-accessdate">. Retrieved <span class="nowrap">2020-09-25</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=IEEE+Communications+Magazine&rft.atitle=Lighting+up+copper&rft.volume=49&rft.issue=5&rft.pages=30-43&rft.date=2011-05&rft_id=info%3Adoi%2F10.1109%2FMCOM.2011.5762795&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A8661205%23id-name%3DS2CID&rft.aulast=Cioffi&rft.aufirst=John&rft_id=https%3A%2F%2Fieeexplore.ieee.org%2Fdocument%2F5762795&rfr_id=info%3Asid%2Fen.wikipedia.org%3AISDN" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="http://www.itu.int/rec/T-REC-I/e"><i>Published recommendations available in English, French and Spanish</i></a> (list), ITU, <a rel="nofollow" class="external text" href="https://web.archive.org/web/20120827155842/http://www.itu.int/rec/T-REC-I/e">archived</a> from the original on 2012-08-27<span class="reference-accessdate">, retrieved <span class="nowrap">2008-08-19</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Published+recommendations+available+in+English%2C+French+and+Spanish&rft.pub=ITU&rft_id=http%3A%2F%2Fwww.itu.int%2Frec%2FT-REC-I%2Fe&rfr_id=info%3Asid%2Fen.wikipedia.org%3AISDN" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFine" class="citation cs2">Fine, <a rel="nofollow" class="external text" href="http://hea-www.harvard.edu/~fine/ISDN/"><i>ISDN</i></a>, Harvard, <a rel="nofollow" class="external text" href="https://web.archive.org/web/20100818174908/http://hea-www.harvard.edu/~fine/ISDN/">archived</a> from the original on 2010-08-18<span class="reference-accessdate">, retrieved <span class="nowrap">2003-08-14</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=ISDN&rft.pub=Harvard&rft.au=Fine&rft_id=http%3A%2F%2Fhea-www.harvard.edu%2F~fine%2FISDN%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AISDN" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFB" class="citation cs2">B, Ralph, <a rel="nofollow" class="external text" href="http://www.ralphb.net/ISDN/"><i>ISDN</i></a>, <a rel="nofollow" class="external text" href="https://web.archive.org/web/20100611215923/http://ralphb.net/ISDN/">archived</a> from the original on 2010-06-11<span class="reference-accessdate">, retrieved <span class="nowrap">2004-11-04</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=ISDN&rft.aulast=B&rft.aufirst=Ralph&rft_id=http%3A%2F%2Fwww.ralphb.net%2FISDN%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AISDN" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20100307025917/http://www.roblee.com/isdn.htm"><i>ISDN</i></a>, Roblee, archived from <a rel="nofollow" class="external text" href="http://www.roblee.com/isdn.htm">the original</a> on 2010-03-07<span class="reference-accessdate">, retrieved <span class="nowrap">2007-08-02</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=ISDN&rft.pub=Roblee&rft_id=http%3A%2F%2Fwww.roblee.com%2Fisdn.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AISDN" class="Z3988"></span></li></ul> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Internet_access" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Internet_access" title="Template:Internet access"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a 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<li><a href="/wiki/Ethernet" title="Ethernet">Ethernet</a></li> <li><a href="/wiki/Fiber_to_the_x" title="Fiber to the x">FTTx</a></li> <li><a href="/wiki/G.hn" title="G.hn">G.hn</a></li> <li><a href="/wiki/Nessum" title="Nessum">Nessum</a></li> <li><a href="/wiki/HomePlug" title="HomePlug">HomePlug</a></li> <li><a href="/wiki/HomePNA" title="HomePNA">HomePNA</a></li> <li><a href="/wiki/IEEE_1901" title="IEEE 1901">IEEE 1901</a></li> <li><a href="/wiki/Integrated_Services_Digital_Network" class="mw-redirect" title="Integrated Services Digital Network">ISDN</a></li> <li><a href="/wiki/Multimedia_over_Coax_Alliance" title="Multimedia over Coax Alliance">MoCA</a></li> <li><a href="/wiki/Passive_optical_network" title="Passive optical network">PON</a></li> <li><a href="/wiki/Power-line_communication" title="Power-line communication">Power-line</a> <ul><li><a href="/wiki/Broadband_over_power_lines" title="Broadband over power lines">Broadband</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Personal_area_network" title="Personal area network">Wireless PAN</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Bluetooth" title="Bluetooth">Bluetooth</a></li> <li><a href="/wiki/Li-Fi" title="Li-Fi">Li-Fi</a></li> <li><a href="/wiki/Wireless_USB" title="Wireless USB">Wireless USB</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Wireless_LAN" title="Wireless LAN">Wireless LAN</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Wi-Fi" title="Wi-Fi">Wi-Fi</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Long range wireless</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/5G_NR" title="5G NR">5G NR</a></li> <li><a href="/wiki/Digital_enhanced_cordless_telecommunications" class="mw-redirect" title="Digital enhanced cordless telecommunications">DECT</a></li> <li><a href="/wiki/Evolution-Data_Optimized" title="Evolution-Data Optimized">EVDO</a></li> <li><a href="/wiki/General_Packet_Radio_Service" title="General Packet Radio Service">GPRS</a></li> <li><a href="/wiki/High_Speed_Packet_Access" title="High Speed Packet Access">HSPA</a></li> <li><a href="/wiki/IBurst" class="mw-redirect" title="IBurst">iBurst</a></li> <li><a href="/wiki/LTE_(telecommunication)" title="LTE (telecommunication)">LTE</a></li> <li><a href="/wiki/Multichannel_Multipoint_Distribution_Service" class="mw-redirect" title="Multichannel Multipoint Distribution Service">MMDS</a></li> <li><a href="/wiki/Municipal_wireless_network" title="Municipal wireless network">Muni Wi-Fi</a></li> <li><a href="/wiki/Satellite_Internet_access" title="Satellite Internet access">Satellite</a></li> <li><a href="/wiki/UMTS-TDD" class="mw-redirect" title="UMTS-TDD">UMTS-TDD</a></li> <li><a href="/wiki/WiMAX" title="WiMAX">WiMAX</a> <ul><li><a href="/wiki/WiBro" title="WiBro">WiBro</a></li></ul></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Telecommunications" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Telecommunications" title="Template:Telecommunications"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Telecommunications" title="Template talk:Telecommunications"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Telecommunications" title="Special:EditPage/Template:Telecommunications"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Telecommunications" style="font-size:114%;margin:0 4em"><a href="/wiki/Telecommunications" title="Telecommunications">Telecommunications</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/History_of_telecommunication" title="History of telecommunication">History</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Beacon#For_defensive_communications" title="Beacon">Beacon</a></li> <li><a href="/wiki/History_of_broadcasting" title="History of broadcasting">Broadcasting</a></li> <li><a href="/wiki/Cable_protection_system" title="Cable protection system">Cable protection system</a></li> <li><a href="/wiki/Cable_television" title="Cable television">Cable TV</a></li> <li><a href="/wiki/Communications_satellite#History" title="Communications satellite">Communications satellite</a></li> <li><a href="/wiki/Computer_network#History" title="Computer network">Computer network</a></li> <li><a href="/wiki/Data_compression" title="Data compression">Data compression</a> <ul><li><a href="/wiki/Audio_coding_format" title="Audio coding format">audio</a></li> <li><a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">DCT</a></li> <li><a href="/wiki/Image_compression" title="Image compression">image</a></li> <li><a href="/wiki/Video_coding_format" title="Video coding format">video</a></li></ul></li> <li><a href="/wiki/Digital_media" title="Digital media">Digital media</a> <ul><li><a href="/wiki/Internet_video" title="Internet video">Internet video</a></li> <li><a href="/wiki/Online_video_platform" title="Online video platform">online video platform</a></li> <li><a href="/wiki/Social_media" title="Social media">social media</a></li> <li><a href="/wiki/Streaming_media" title="Streaming media">streaming</a></li></ul></li> <li><a href="/wiki/Drums_in_communication" title="Drums in communication">Drums</a></li> <li><a href="/wiki/Edholm%27s_law" title="Edholm's law">Edholm's law</a></li> <li><a href="/wiki/Electrical_telegraph#History" title="Electrical telegraph">Electrical telegraph</a></li> <li><a href="/wiki/Fax#History" title="Fax">Fax</a></li> <li><a href="/wiki/Heliograph#History" title="Heliograph">Heliographs</a></li> <li><a href="/wiki/Hydraulic_telegraph#Greek_hydraulic_semaphore_system" title="Hydraulic telegraph">Hydraulic telegraph</a></li> <li><a href="/wiki/Information_Age" title="Information Age">Information Age</a></li> <li><a href="/wiki/Information_revolution" class="mw-redirect" title="Information revolution">Information revolution</a></li> <li><a href="/wiki/History_of_the_Internet" title="History of the Internet">Internet</a></li> <li><a href="/wiki/Mass_media#History" title="Mass media">Mass media</a></li> <li><a href="/wiki/History_of_mobile_phones" title="History of mobile phones">Mobile phone</a> <ul><li><a href="/wiki/Smartphone" title="Smartphone">Smartphone</a></li></ul></li> <li><a href="/wiki/Optical_communication" title="Optical communication">Optical telecommunication</a></li> <li><a href="/wiki/Optical_telegraph" title="Optical telegraph">Optical telegraphy</a></li> <li><a href="/wiki/Pager" title="Pager">Pager</a></li> <li><a href="/wiki/Photophone" title="Photophone">Photophone</a></li> <li><a href="/wiki/History_of_prepaid_mobile_phones" title="History of prepaid mobile phones">Prepaid mobile phone</a></li> <li><a href="/wiki/History_of_radio" title="History of radio">Radio</a></li> <li><a href="/wiki/Radiotelephone" title="Radiotelephone">Radiotelephone</a></li> <li><a href="/wiki/Communications_satellite" title="Communications satellite">Satellite communications</a></li> <li><a href="/wiki/Semaphore" title="Semaphore">Semaphore</a> <ul><li><a href="/wiki/Phryctoria" title="Phryctoria">Phryctoria</a></li></ul></li> <li><a href="/wiki/Semiconductor" title="Semiconductor">Semiconductor</a> <ul><li><a href="/wiki/Semiconductor_device" title="Semiconductor device">device</a></li> <li><a href="/wiki/MOSFET" title="MOSFET">MOSFET</a></li> <li><a href="/wiki/History_of_the_transistor" title="History of the transistor">transistor</a></li></ul></li> <li><a href="/wiki/Smoke_signal" title="Smoke signal">Smoke signals</a></li> <li><a href="/wiki/History_of_telecommunication" title="History of telecommunication">Telecommunications history</a></li> <li><a href="/wiki/Telautograph" title="Telautograph">Telautograph</a></li> <li><a href="/wiki/Telegraphy" title="Telegraphy">Telegraphy</a></li> <li><a href="/wiki/Teleprinter" title="Teleprinter">Teleprinter</a> (teletype)</li> <li><a href="/wiki/History_of_the_telephone" title="History of the telephone">Telephone</a></li> <li><i><a href="/wiki/The_Telephone_Cases" title="The Telephone Cases">The Telephone Cases</a></i></li> <li><a href="/wiki/History_of_television" title="History of television">Television</a> <ul><li><a href="/wiki/Digital_television" title="Digital television">digital</a></li> <li><a href="/wiki/Streaming_television" title="Streaming television">streaming</a></li></ul></li> <li><a href="/wiki/Submarine_communications_cable#Early_history:_telegraph_and_coaxial_cables" title="Submarine communications cable">Undersea telegraph line</a></li> <li><a href="/wiki/History_of_videotelephony" title="History of videotelephony">Videotelephony</a></li> <li><a href="/wiki/Whistled_language" title="Whistled language">Whistled language</a></li> <li><a href="/wiki/Wireless_revolution" class="mw-redirect" title="Wireless revolution">Wireless revolution</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Pioneers</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Nasir_Ahmed_(engineer)" title="Nasir Ahmed (engineer)">Nasir Ahmed</a></li> <li><a href="/wiki/Edwin_Howard_Armstrong" title="Edwin Howard Armstrong">Edwin Howard Armstrong</a></li> <li><a href="/wiki/Mohamed_M._Atalla" title="Mohamed M. Atalla">Mohamed M. Atalla</a></li> <li><a href="/wiki/John_Logie_Baird" title="John Logie Baird">John Logie Baird</a></li> <li><a href="/wiki/Paul_Baran" title="Paul Baran">Paul Baran</a></li> <li><a href="/wiki/John_Bardeen" title="John Bardeen">John Bardeen</a></li> <li><a href="/wiki/Alexander_Graham_Bell" title="Alexander Graham Bell">Alexander Graham Bell</a></li> <li><a href="/wiki/Emile_Berliner" title="Emile Berliner">Emile Berliner</a></li> <li><a href="/wiki/Tim_Berners-Lee" title="Tim Berners-Lee">Tim Berners-Lee</a></li> <li><a href="/wiki/Francis_Blake_(inventor)" title="Francis Blake (inventor)">Francis Blake</a></li> <li><a href="/wiki/Jagadish_Chandra_Bose" title="Jagadish Chandra Bose">Jagadish Chandra Bose</a></li> <li><a href="/wiki/Charles_Bourseul" title="Charles Bourseul">Charles Bourseul</a></li> <li><a href="/wiki/Walter_Houser_Brattain" title="Walter Houser Brattain">Walter Houser Brattain</a></li> <li><a href="/wiki/Vint_Cerf" title="Vint Cerf">Vint Cerf</a></li> <li><a href="/wiki/Claude_Chappe" title="Claude Chappe">Claude Chappe</a></li> <li><a href="/wiki/Yogen_Dalal" class="mw-redirect" title="Yogen Dalal">Yogen Dalal</a></li> <li><a href="/wiki/Daniel_Davis_Jr." title="Daniel Davis Jr.">Daniel Davis Jr.</a></li> <li><a href="/wiki/Donald_Davies" title="Donald Davies">Donald Davies</a></li> <li><a href="/wiki/Amos_Dolbear" title="Amos Dolbear">Amos Dolbear</a></li> <li><a href="/wiki/Thomas_Edison" title="Thomas Edison">Thomas Edison</a></li> <li><a href="/wiki/Lee_de_Forest" title="Lee de Forest">Lee de Forest</a></li> <li><a href="/wiki/Philo_Farnsworth" title="Philo Farnsworth">Philo Farnsworth</a></li> <li><a href="/wiki/Reginald_Fessenden" title="Reginald Fessenden">Reginald Fessenden</a></li> <li><a href="/wiki/Elisha_Gray" title="Elisha Gray">Elisha Gray</a></li> <li><a href="/wiki/Oliver_Heaviside" title="Oliver Heaviside">Oliver Heaviside</a></li> <li><a href="/wiki/Robert_Hooke" title="Robert Hooke">Robert Hooke</a></li> <li><a href="/wiki/Erna_Schneider_Hoover" title="Erna Schneider Hoover">Erna Schneider Hoover</a></li> <li><a href="/wiki/Harold_Hopkins_(physicist)" title="Harold Hopkins (physicist)">Harold Hopkins</a></li> <li><a href="/wiki/Gardiner_Greene_Hubbard" title="Gardiner Greene Hubbard">Gardiner Greene Hubbard</a></li> <li><a href="/wiki/List_of_Internet_pioneers" title="List of Internet pioneers">Internet pioneers</a></li> <li><a href="/wiki/Bob_Kahn" class="mw-redirect" title="Bob Kahn">Bob Kahn</a></li> <li><a href="/wiki/Dawon_Kahng" title="Dawon Kahng">Dawon Kahng</a></li> <li><a href="/wiki/Charles_K._Kao" title="Charles K. Kao">Charles K. Kao</a></li> <li><a href="/wiki/Narinder_Singh_Kapany" title="Narinder Singh Kapany">Narinder Singh Kapany</a></li> <li><a href="/wiki/Hedy_Lamarr" title="Hedy Lamarr">Hedy Lamarr</a></li> <li><a href="/wiki/Roberto_Landell_de_Moura" title="Roberto Landell de Moura">Roberto Landell de Moura</a></li> <li><a href="/wiki/Innocenzo_Manzetti" title="Innocenzo Manzetti">Innocenzo Manzetti</a></li> <li><a href="/wiki/Guglielmo_Marconi" title="Guglielmo Marconi">Guglielmo Marconi</a></li> <li><a href="/wiki/Robert_Metcalfe" title="Robert Metcalfe">Robert Metcalfe</a></li> <li><a href="/wiki/Antonio_Meucci" title="Antonio Meucci">Antonio Meucci</a></li> <li><a href="/wiki/Samuel_Morse" title="Samuel Morse">Samuel Morse</a></li> <li><a href="/wiki/Jun-ichi_Nishizawa" title="Jun-ichi Nishizawa">Jun-ichi Nishizawa</a></li> <li><a href="/wiki/Charles_Grafton_Page" title="Charles Grafton Page">Charles Grafton Page</a></li> <li><a href="/wiki/Radia_Perlman" title="Radia Perlman">Radia Perlman</a></li> <li><a href="/wiki/Alexander_Stepanovich_Popov" class="mw-redirect" title="Alexander Stepanovich Popov">Alexander Stepanovich Popov</a></li> <li><a href="/wiki/Tivadar_Pusk%C3%A1s" title="Tivadar Puskás">Tivadar Puskás</a></li> <li><a href="/wiki/Johann_Philipp_Reis" title="Johann Philipp Reis">Johann Philipp Reis</a></li> <li><a href="/wiki/Claude_Shannon" title="Claude Shannon">Claude Shannon</a></li> <li><a href="/wiki/Almon_Brown_Strowger" title="Almon Brown Strowger">Almon Brown Strowger</a></li> <li><a href="/wiki/Henry_Sutton_(inventor)" title="Henry Sutton (inventor)">Henry Sutton</a></li> <li><a href="/wiki/Charles_Sumner_Tainter" title="Charles Sumner Tainter">Charles Sumner Tainter</a></li> <li><a href="/wiki/Nikola_Tesla" title="Nikola Tesla">Nikola Tesla</a></li> <li><a href="/wiki/Camille_Tissot" title="Camille Tissot">Camille Tissot</a></li> <li><a href="/wiki/Alfred_Vail" title="Alfred Vail">Alfred Vail</a></li> <li><a href="/wiki/Thomas_A._Watson" title="Thomas A. Watson">Thomas A. Watson</a></li> <li><a href="/wiki/Charles_Wheatstone" title="Charles Wheatstone">Charles Wheatstone</a></li> <li><a href="/wiki/Vladimir_K._Zworykin" title="Vladimir K. Zworykin">Vladimir K. Zworykin</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Transmission_medium" title="Transmission medium">Transmission<br />media</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Coaxial_cable" title="Coaxial cable">Coaxial cable</a></li> <li><a href="/wiki/Fiber-optic_communication" title="Fiber-optic communication">Fiber-optic communication</a> <ul><li><a href="/wiki/Optical_fiber" title="Optical fiber">optical fiber</a></li></ul></li> <li><a href="/wiki/Free-space_optical_communication" title="Free-space optical communication">Free-space optical communication</a></li> <li><a href="/wiki/Molecular_communication" title="Molecular communication">Molecular communication</a></li> <li><a href="/wiki/Radio_wave" title="Radio wave">Radio waves</a> <ul><li><a href="/wiki/Wireless" title="Wireless">wireless</a></li></ul></li> <li><a href="/wiki/Transmission_line" title="Transmission line">Transmission line</a> <ul><li><a href="/wiki/Telecommunication_circuit" title="Telecommunication circuit">telecommunication circuit</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Network_topology" title="Network topology">Network topology</a><br />and switching</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Bandwidth_(computing)" title="Bandwidth (computing)">Bandwidth</a></li> <li><a href="/wiki/Telecommunications_link" title="Telecommunications link">Links</a></li> <li><a href="/wiki/Node_(networking)" title="Node (networking)">Nodes</a> <ul><li><a href="/wiki/Terminal_(telecommunication)" title="Terminal (telecommunication)">terminal</a></li></ul></li> <li><a href="/wiki/Network_switch" title="Network switch">Network switching</a> <ul><li><a href="/wiki/Circuit_switching" title="Circuit switching">circuit</a></li> <li><a href="/wiki/Packet_switching" title="Packet switching">packet</a></li></ul></li> <li><a href="/wiki/Telephone_exchange" title="Telephone exchange">Telephone exchange</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Multiplexing" title="Multiplexing">Multiplexing</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Space-division_multiple_access" title="Space-division multiple access">Space-division</a></li> <li><a href="/wiki/Frequency-division_multiplexing" title="Frequency-division multiplexing">Frequency-division</a></li> <li><a href="/wiki/Time-division_multiplexing" title="Time-division multiplexing">Time-division</a></li> <li><a href="/wiki/Polarization-division_multiplexing" title="Polarization-division multiplexing">Polarization-division</a></li> <li><a href="/wiki/Orbital_angular_momentum_multiplexing" title="Orbital angular momentum multiplexing">Orbital angular-momentum</a></li> <li><a href="/wiki/Code-division_multiple_access" title="Code-division multiple access">Code-division</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Concepts</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Communication_protocol" title="Communication protocol">Communication protocol</a></li> <li><a href="/wiki/Computer_network" title="Computer network">Computer network</a></li> <li><a href="/wiki/Data_communication" title="Data communication">Data transmission</a></li> <li><a href="/wiki/Store_and_forward" title="Store and forward">Store and forward</a></li> <li><a href="/wiki/Telecommunications_equipment" title="Telecommunications equipment">Telecommunications equipment</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Telecommunications_network" title="Telecommunications network">Types of network</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Cellular_network" title="Cellular network">Cellular network</a></li> <li><a href="/wiki/Ethernet" title="Ethernet">Ethernet</a></li> <li><a href="/wiki/Integrated_Services_Digital_Network" class="mw-redirect" title="Integrated Services Digital Network">ISDN</a></li> <li><a href="/wiki/Local_area_network" title="Local area network">LAN</a></li> <li><a href="/wiki/Mobile_telephony" title="Mobile telephony">Mobile</a></li> <li><a href="/wiki/Next-generation_network" title="Next-generation network">NGN</a></li> <li><a href="/wiki/Public_switched_telephone_network" title="Public switched telephone network">Public Switched Telephone</a></li> <li><a href="/wiki/Radio_network" title="Radio network">Radio</a></li> <li><a href="/wiki/Television_broadcasting" class="mw-redirect" title="Television broadcasting">Television</a></li> <li><a href="/wiki/Telex" title="Telex">Telex</a></li> <li><a href="/wiki/UUCP" title="UUCP">UUCP</a></li> <li><a href="/wiki/Wide_area_network" title="Wide area network">WAN</a></li> <li><a href="/wiki/Wireless_network" title="Wireless network">Wireless network</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Telecommunications_network" title="Telecommunications network">Notable networks</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ARPANET" title="ARPANET">ARPANET</a></li> <li><a href="/wiki/BITNET" title="BITNET">BITNET</a></li> <li><a href="/wiki/CYCLADES" title="CYCLADES">CYCLADES</a></li> <li><a href="/wiki/FidoNet" title="FidoNet">FidoNet</a></li> <li><a href="/wiki/Internet" title="Internet">Internet</a></li> <li><a href="/wiki/Internet2" title="Internet2">Internet2</a></li> <li><a href="/wiki/JANET" title="JANET">JANET</a></li> <li><a href="/wiki/NPL_network" title="NPL network">NPL network</a></li> <li><a href="/wiki/Toasternet" title="Toasternet">Toasternet</a></li> <li><a href="/wiki/Usenet" title="Usenet">Usenet</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Locations</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Category:Telecommunications_in_Africa" title="Category:Telecommunications in Africa">Africa</a></li> <li>Americas <ul><li><a href="/wiki/Category:Telecommunications_in_North_America" title="Category:Telecommunications in North America">North</a></li> <li><a href="/wiki/Category:Telecommunications_in_South_America" title="Category:Telecommunications in South America">South</a></li></ul></li> <li><a href="/wiki/Category:Communications_in_Antarctica" title="Category:Communications in Antarctica">Antarctica</a></li> <li><a href="/wiki/Category:Telecommunications_in_Asia" title="Category:Telecommunications in Asia">Asia</a></li> <li><a href="/wiki/Category:Telecommunications_in_Europe" title="Category:Telecommunications in Europe">Europe</a></li> <li><a href="/wiki/Category:Telecommunications_in_Oceania" title="Category:Telecommunications in Oceania">Oceania</a></li> <li>(<a href="/wiki/List_of_telecommunications_regulatory_bodies" title="List of telecommunications regulatory bodies">Global telecommunications regulation bodies</a>)</li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="nowrap"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/16px-Telecom-icon.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/24px-Telecom-icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/32px-Telecom-icon.svg.png 2x" data-file-width="500" data-file-height="500" /></span></span> </span><a href="/wiki/Portal:Telecommunication" title="Portal:Telecommunication">Telecommunication portal</a></li> <li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Telecommunications" title="Category:Telecommunications">Category</a></li> <li><span class="noviewer" typeof="mw:File"><span title="List-Class article"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/16px-Symbol_list_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/23px-Symbol_list_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/31px-Symbol_list_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Outline_of_telecommunication" title="Outline of telecommunication">Outline</a></li> <li><span class="noviewer" typeof="mw:File"><span title="Commons page"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/12px-Commons-logo.svg.png" decoding="async" width="12" height="16" class="mw-file-element" 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