{"id":21762,"date":"2018-06-29T14:55:01","date_gmt":"2018-06-29T18:55:01","guid":{"rendered":"http:\/\/blog.voipsupply.com\/?p=21762"},"modified":"2024-01-31T10:05:24","modified_gmt":"2024-01-31T15:05:24","slug":"fxs-and-fxo-you-should-be-in-the-know","status":"publish","type":"post","link":"https:\/\/www.voipsupply.com\/blog\/voip-insider\/fxs-and-fxo-you-should-be-in-the-know\/","title":{"rendered":"What are FXS and FXO ports? What are they used for?"},"content":{"rendered":"<p><b>Editor\u2019s Note: This article was originally posted in October 2015 and has been fully updated for accuracy and comprehensiveness in June 2018.<\/b><\/p>\n<p><span style=\"font-weight: 400;\">If you are researching into deploying a VoIP Telephony System on your own for the first time, you are probably seeing FXS and FXO acronyms all over the place. &nbsp;When you\u2019re <\/span><a href=\"\/new-to-voip\" onclick=\"ga('send', 'event', 'voip-insider-blog-post', 'click', 'new to voip');\"><span style=\"font-weight: 400;\">new to VoIP<\/span><\/a><span style=\"font-weight: 400;\"> learning it can be very difficult. Hopefully, we can help to make a little sense of FXS\/FXO for you.<\/span><\/p>\n<p><iframe loading=\"lazy\" title=\"Solving Problems With VoIP Supply | What is FXS\/FXO?\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/QoC2cAkPDmY?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><\/p>\n<h2><b>What is an FXS port?<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">FXS stands for foreign exchange subscriber. An FXS port is an interface that connects station devices such as your phones or PBX to a VoIP adapter. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">FXS is an RJ11 port that connects internally to an analog office phone or fax machine. &nbsp;Think of the S as meaning a station or a cubicle. Any FXS port is going to connect to an analog DEVICE and the cable from the port to the device will never leave the building. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">Now, on to the FXO ports&#8230;<\/span><\/p>\n<h2><b>What is an FXO port?<\/b><\/h2>\n<p><span style=\"font-weight: 400;\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-269763 alignright\" src=\"\/blog\/voip-insider\/files\/2015\/10\/fxo.jpg\" alt=\"\" width=\"254\" height=\"105\" srcset=\"https:\/\/www.voipsupply.com\/blog\/voip-insider\/files\/2015\/10\/fxo.jpg 295w, https:\/\/www.voipsupply.com\/blog\/voip-insider\/files\/2015\/10\/fxo-150x62.jpg 150w\" sizes=\"auto, (max-width: 254px) 100vw, 254px\" \/>FXO stands for foreign exchange office. An FXO port is an interface that connects your Plain Old Telephone Service (POTS) line to a VoIP adapter.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">It designates a telephone signaling interface that receives POTS (plain old telephone service). Um\u2026 ok. Let\u2019s put it this way, FXO is a port that will connect a device to an outside telephone line. &nbsp;Think \u201cO\u201d for \u201cOutside\u201d. Picture an RJ11 wall jack that connects to a box in your basement which is connected to the line from your house to the nearest telephone pole on your street. Any RJ11 port on a device that is headed towards that wall jack is an FXO port. It connects your device to the \u201coutside\u201d world or your local area telephone \u201coffice\u201d.<\/span><\/p>\n<h2><b>What is an FXO\/FXS port used for?<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">These ports are used to allow you to connect your analog phones to a VoIP system. An FXS port helps you connect your analog fax machine to your VoIP phone system; an FXO port enables you to use analog telephone lines with your VoIP phone system.<\/span><\/p>\n<h3><b>An FXO\/FXS VoIP Adapter and Gateway <\/b><\/h3>\n<p><span style=\"font-weight: 400;\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-212713 alignleft\" src=\"\/blog\/voip-insider\/files\/2016\/09\/HT812-ata.png\" alt=\"\" width=\"163\" height=\"73\" srcset=\"https:\/\/www.voipsupply.com\/blog\/voip-insider\/files\/2016\/09\/HT812-ata.png 368w, https:\/\/www.voipsupply.com\/blog\/voip-insider\/files\/2016\/09\/HT812-ata-150x67.png 150w, https:\/\/www.voipsupply.com\/blog\/voip-insider\/files\/2016\/09\/HT812-ata-300x135.png 300w\" sizes=\"auto, (max-width: 163px) 100vw, 163px\" \/>FXS and FXO ports are important when dealing with <\/span><a href=\"\/voip-adapters\" onclick=\"ga('send', 'event', 'voip-insider-blog-post', 'click', 'voip adapters');\"><span style=\"font-weight: 400;\">VoIP adapters<\/span><\/a><span style=\"font-weight: 400;\"> and <\/span><a href=\"\/voip-gateways\" onclick=\"ga('send', 'event', 'voip-insider-blog-post', 'click', 'voip gateways');\"><span style=\"font-weight: 400;\">VoIP Gateways<\/span><\/a><span style=\"font-weight: 400;\">. The number of telephones, PBX systems or PSTN lines you are looking to connect to a VoIP adapter or gateway determines how many of each port you will need. <\/span><\/p>\n<p><span style=\"font-weight: 400;\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-128273 alignright\" src=\"\/blog\/voip-insider\/files\/2015\/12\/Patton-SmartNode-40170-Single-Port-PRI-VoIP-Gateway-1.jpg\" alt=\"\" width=\"178\" height=\"178\" srcset=\"https:\/\/www.voipsupply.com\/blog\/voip-insider\/files\/2015\/12\/Patton-SmartNode-40170-Single-Port-PRI-VoIP-Gateway-1.jpg 600w, https:\/\/www.voipsupply.com\/blog\/voip-insider\/files\/2015\/12\/Patton-SmartNode-40170-Single-Port-PRI-VoIP-Gateway-1-150x150.jpg 150w, https:\/\/www.voipsupply.com\/blog\/voip-insider\/files\/2015\/12\/Patton-SmartNode-40170-Single-Port-PRI-VoIP-Gateway-1-300x300.jpg 300w\" sizes=\"auto, (max-width: 178px) 100vw, 178px\" \/>An FXS gateway is used to connect your traditional telephones and fax machines to a VoIP Phone system; an FXO gateway is used to connect your VoIP phone system to your PSTN lines.<\/span><\/p>\n<h3><b>VoIP Failover<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">In the event of failure, the most critical phone systems should have a failover feature so phone calls or faxes may continue during the downtime. You can still make telephone calls via the POTS line. &nbsp;Also, you can use the FXO port to make free local calls on your PSTN line.<\/span><br \/>\n<!--HubSpot Call-to-Action Code --><span id=\"hs-cta-wrapper-7cfff716-88f0-494e-aefb-1d9b991f61e7\" class=\"hs-cta-wrapper\"><span id=\"hs-cta-7cfff716-88f0-494e-aefb-1d9b991f61e7\" class=\"hs-cta-node hs-cta-7cfff716-88f0-494e-aefb-1d9b991f61e7\"><!-- [if lte IE 8]>\n\n\n<div id=\"hs-cta-ie-element\"><\/div>\n\n\n<![endif]--><a class=\"post-thumbnail\" href=\"https:\/\/cta-redirect.hubspot.com\/cta\/redirect\/464097\/7cfff716-88f0-494e-aefb-1d9b991f61e7\" onclick=\"ga('send', 'event', 'voip-insider-blog-post', 'click', 'cta');\"><img decoding=\"async\" id=\"hs-cta-img-7cfff716-88f0-494e-aefb-1d9b991f61e7\" class=\"hs-cta-img aligncenter\" style=\"border-width: 0px;\" src=\"https:\/\/no-cache.hubspot.com\/cta\/default\/464097\/7cfff716-88f0-494e-aefb-1d9b991f61e7.png\" alt=\"See All the VoIP Guides\"><\/a><\/span><\/span><!-- end HubSpot Call-to-Action Code --><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Editor\u2019s Note: This article was originally posted in October 2015 and has been fully updated for accuracy and comprehensiveness in June 2018. If you are researching into deploying a VoIP Telephony System on your own for the first time, you are probably seeing FXS and FXO acronyms all over the place. &nbsp;When you\u2019re new to [&hellip;]<\/p>\n","protected":false},"author":123,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1221,1219,1225,1223],"tags":[],"class_list":["post-21762","post","type-post","status-publish","format-standard","hentry","category-small-business-voip","category-voip-education","category-voip-hardware","category-voip-systems"],"_links":{"self":[{"href":"https:\/\/www.voipsupply.com\/blog\/voip-insider\/wp-json\/wp\/v2\/posts\/21762","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.voipsupply.com\/blog\/voip-insider\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.voipsupply.com\/blog\/voip-insider\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.voipsupply.com\/blog\/voip-insider\/wp-json\/wp\/v2\/users\/123"}],"replies":[{"embeddable":true,"href":"https:\/\/www.voipsupply.com\/blog\/voip-insider\/wp-json\/wp\/v2\/comments?post=21762"}],"version-history":[{"count":14,"href":"https:\/\/www.voipsupply.com\/blog\/voip-insider\/wp-json\/wp\/v2\/posts\/21762\/revisions"}],"predecessor-version":[{"id":310171,"href":"https:\/\/www.voipsupply.com\/blog\/voip-insider\/wp-json\/wp\/v2\/posts\/21762\/revisions\/310171"}],"wp:attachment":[{"href":"https:\/\/www.voipsupply.com\/blog\/voip-insider\/wp-json\/wp\/v2\/media?parent=21762"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.voipsupply.com\/blog\/voip-insider\/wp-json\/wp\/v2\/categories?post=21762"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.voipsupply.com\/blog\/voip-insider\/wp-json\/wp\/v2\/tags?post=21762"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}