Editing Voice over IP (section)

==Adoption==
===Consumer market===
[[File:Voip-typical.gif|thumb|Example of residential network including VoIP]]
Mass-market VoIP services use existing [[broadband Internet access]], by which subscribers place and receive telephone calls in much the same manner as they would via the PSTN. Full-service VoIP phone companies provide inbound and outbound service with [[direct inbound dialing]]. Many offer unlimited domestic calling and sometimes international calls for a flat monthly subscription fee. Phone calls between subscribers of the same provider are usually free when flat-fee service is not available.<ref>{{Cite web |date=2010-11-18 |title=Voice Over Internet Protocol (VoIP) |url=https://www.fcc.gov/general/voice-over-internet-protocol-voip |access-date=2022-07-19 |website=Federal Communications Commission |language=en}}</ref>

A VoIP phone is necessary to connect to a VoIP service provider. This can be implemented in several ways:
* Dedicated VoIP phones connect directly to the IP network using technologies such as wired [[Ethernet]] or [[Wi-Fi]]. These are typically designed in the style of traditional digital business telephones.
* An [[analog telephone adapter]] connects to the network and implements the electronics and firmware to operate a conventional analog telephone attached through a modular phone jack. Some residential Internet gateways and [[cable modem]]s have this function built in.
* [[Softphone]] application software installed on a networked computer that is equipped with a microphone and speaker, or headset. The application typically presents a dial pad and display field to the user to operate the application by mouse clicks or keyboard input.<ref>{{Cite web |title=VoIP (v77) |url=https://mendocinobroadband.org/wp-content/uploads/VoIP-v77.pdf}}</ref>

===PSTN and mobile network providers===
It is increasingly common for telecommunications providers to use VoIP telephony over dedicated and public IP networks as a [[Backhaul (telecommunications)|backhaul]] to connect switching centers and to interconnect with other telephony network providers; this is often referred to as ''IP backhaul''.<ref>{{cite web|title=WIRELESS: Carriers look to IP for backhaul |url=http://www.eetimes.com/electronics-news/4052152/WIRELESS-Carriers-look-to-IP-for-back-haul |website=www.eetimes.com |publisher=EE Times |access-date=April 8, 2015 |url-status=unfit |archive-url=https://web.archive.org/web/20110809025050/http://www.eetimes.com/electronics-news/4052152/WIRELESS-Carriers-look-to-IP-for-back-haul |archive-date=August 9, 2011 }}</ref><ref>{{cite web|title=Mobile's IP challenge |url=http://www.totaltele.com/View.aspx?ID=77588&t=4 |website=www.totaltele.com |publisher=Total Telecom Online |access-date=April 8, 2015 |url-status=unfit |archive-url=https://web.archive.org/web/20060217064211/http://www.totaltele.com/View.aspx?ID=77588&t=4 |archive-date=February 17, 2006 }}</ref>

[[Smartphones]] may have SIP clients built into the firmware or available as an application download.<ref>{{cite web |url=https://www.callcentric.com/support/device/android/sip_client |title=Android SIP Client |access-date=January 30, 2018}}</ref><ref>{{cite web |url=https://www.lifewire.com/apps-for-sip-on-android-3426471 |title=Learn to Make Free or Inexpensive Calls Using SIP on Android |access-date=January 30, 2018}}</ref>

===Corporate use===
Because of the bandwidth efficiency and low costs that VoIP technology can provide, businesses are migrating from traditional copper-wire telephone systems to VoIP systems to reduce their monthly phone costs. In 2008, 80% of all new [[Private branch exchange]] (PBX) lines installed internationally were VoIP.<ref>{{cite web|url=http://www.axiaaudio.com/tech/voip/default.htm|title=VoIP in the Broadcast Studio|author=Michael Dosch and Steve Church|publisher=Axia Audio|access-date=June 21, 2011|url-status=dead|archive-url=https://web.archive.org/web/20111007231611/http://www.axiaaudio.com/tech/voip/default.htm|archive-date=October 7, 2011}}</ref> For example, in the United States, the [[Social Security Administration]] is converting its field offices of 63,000 workers from traditional phone installations to a VoIP infrastructure carried over its existing data network.<ref>{{cite web|first=William|last=Jackson|title=SSA goes big on VOIP|url=http://gcn.com/Articles/2009/06/01/SSA-VOIP-implementation.aspx?s=gcndaily_280509&Page=1|publisher=Government Computer News|date=May 27, 2009|access-date=May 28, 2009|archive-date=July 28, 2011|archive-url=https://web.archive.org/web/20110728164137/http://gcn.com/Articles/2009/06/01/SSA-VOIP-implementation.aspx?s=gcndaily_280509&Page=1|url-status=dead}}</ref><ref>{{cite web|url=http://www.govtech.com/gt/275677|title=Social Security to Build "World's Largest VOIP"|publisher=Government Technology|url-status=live|archive-url=https://web.archive.org/web/20090602094711/http://www.govtech.com/gt/275677|archive-date=June 2, 2009|access-date=May 29, 2009}}</ref>

VoIP allows both voice and [[data communication]]s to be run over a single network, which can significantly reduce infrastructure costs. The prices of extensions on VoIP are lower than for PBX and key systems. VoIP switches may run on commodity hardware, such as [[personal computer]]s. Rather than closed architectures, these devices rely on standard interfaces.<ref name="Korzeniowski">{{cite journal |url=https://www.forbes.com/2009/01/08/small-business-voip-ent-tech-cx_bm_0108bmightytech09.html/ |title=Three Technologies You Need In 2009 |date=January 8, 2009 |last=Korzeniowski |first=Peter |access-date=March 2, 2009 |journal=Forbes}}</ref> VoIP devices have simple, intuitive user interfaces, so users can often make simple system configuration changes. Dual-mode phones enable users to continue their conversations as they move between an outside cellular service and an internal [[Wi-Fi]] network, so that it is no longer necessary to carry both a desktop phone and a cell phone. Maintenance becomes simpler as there are fewer devices to oversee.<ref name="Korzeniowski"/>

VoIP solutions aimed at businesses have evolved into [[unified communications]] services that treat all communications—phone calls, faxes, voice mail, e-mail, web conferences, and more—as discrete units that can all be delivered via any means and to any handset, including cellphones. Two kinds of service providers are operating in this space: one set is focused on VoIP for medium to large enterprises, while another is targeting the small-to-medium business (SMB) market.<ref>{{cite journal|url=https://www.forbes.com/2008/12/09/skype-vonage-ringcentral_leadership_clayton_in_rc_1209claytonchristensen_inl.html |title= Businesses Move To Voice-Over-IP|date=December 9, 2008|last=Callahan|first=Renee|access-date=March 3, 2009|journal=Forbes}}</ref>

[[Skype]], which originally marketed itself as a service among friends, began to cater to businesses in 2009, providing free-of-charge connections between any users on the Skype network and connecting to and from ordinary PSTN telephones for a charge.<ref>{{cite web|url=http://www.skype.com/business/allfeatures/3skypephone/|title=Skype For Business|access-date=March 16, 2009|publisher=skype.com}}</ref>