Not always. VoIP requires an IP network path between your phone and the system that handles its calls, and that path can be public or private. A call can cross the internet, run over a private connection to your provider, or stay between two phones inside one building. Which of those your calls use depends on how the service is set up. To call ordinary phone numbers, the call also has to reach a service connected to the public telephone network.
\n","summary":"Not always. VoIP needs an IP network path between the phone and the system that handles its calls. That path can be the public internet, a private connection to the provider or an office network with the phone system on site, depending on how the service is set up.","publishedAt":"2026-07-03T03:26:50.582","verifiedAt":"2026-09-14T00:00:00","editorialStatus":"APPROVED","lastReviewedAt":"2026-10-10T04:38:41.084","nextReviewDueAt":"2026-12-14T00:00:00","templateVersion":"v2","aliases":["Can VoIP work without the internet?","Do you need internet for VoIP?","Does a VoIP phone need Wi-Fi?","Can you use VoIP without an internet connection?","Will VoIP work if the internet goes down?","Does VoIP use mobile data?","How much internet does VoIP need?","Does VoIP need broadband?","Can VoIP run over cellular data?","Can VoIP run over a private network or MPLS?","Does a VoIP phone work during a power outage?","How much data does a ten-minute VoIP call use?"],"confidenceScore":90,"confidenceLabel":"High","canonicalUrl":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"contributorOrganizationProfile":null,"contributorPerson":null,"sections":[{"id":"ff2ea4d6-cf18-451c-89c2-80275bc21d3b","sectionKey":"where_a_voip_call_can_travel","sectionType":"table_section","heading":"Where a VoIP call can travel","introMarkdown":null,"introHtml":null,"outroMarkdown":null,"outroHtml":null,"contentJson":{"rows":[{"cells":["Hosted phone service reached over your regular internet connection","Yes","Working internet service at your site"]},{"cells":["An access connection on your voice provider's own network","Not between your site and the provider's voice switch","That provider's connection to your building"]},{"cells":["An internal call on a phone system kept on site","No","The local network and the phone system staying up"]}],"columns":["Path","Does it cross the public internet?","What it depends on"]},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":10},{"id":"3b5849c1-0e41-467e-980b-c044a3d06757","sectionKey":"what_the_ip_in_voip_stands_for","sectionType":"markdown_section","heading":"What the IP in VoIP stands for","introMarkdown":"The \"IP\" in VoIP is Internet Protocol, the method networks use to address data and move it. The public internet runs on that protocol. So does the network inside your office, and so does a private link between two sites. A VoIP phone needs a network path to the system that handles its calls and a path for the audio. Any IP network that reaches both can carry the call.\n\nThe internet is one such network. The FCC's [consumer guide to VoIP](https://www.fcc.gov/consumers/guides/voice-over-internet-protocol-voip) describes the technology as converting your voice into a digital signal that can travel over the internet. The [federal definition of interconnected VoIP](https://www.law.cornell.edu/cfr/text/47/9.3), the kind of service that exchanges calls with the public telephone network, lists a broadband connection from the user's location among its conditions. So an interconnected VoIP service, by that definition, needs a broadband connection at your end. Whether that connection carries the call across the public internet or along a private path is a matter of how the service is set up.\n\nWi-Fi causes a related mix-up. Wi-Fi connects a phone or laptop to your local network. The internet service that network uses is a separate thing. A softphone on Wi-Fi with no internet behind it can still reach anything that network routes to, such as a phone system on site or a private link to another office. It can't reach a service that's only available over the internet.\n\nHow much connection a call needs is its own question. We answer it in [how much bandwidth a VoIP call uses](https://www.answerstack.io/q/how-much-bandwidth-does-a-voip-call-use), and we compare access types in [what type of internet connection you need for VoIP](https://www.answerstack.io/q/what-type-of-internet-connection-do-i-need-for-voip).","introHtml":"The "IP" in VoIP is Internet Protocol, the method networks use to address data and move it. The public internet runs on that protocol. So does the network inside your office, and so does a private link between two sites. A VoIP phone needs a network path to the system that handles its calls and a path for the audio. Any IP network that reaches both can carry the call.
\nThe internet is one such network. The FCC's consumer guide to VoIP describes the technology as converting your voice into a digital signal that can travel over the internet. The federal definition of interconnected VoIP, the kind of service that exchanges calls with the public telephone network, lists a broadband connection from the user's location among its conditions. So an interconnected VoIP service, by that definition, needs a broadband connection at your end. Whether that connection carries the call across the public internet or along a private path is a matter of how the service is set up.
\nWi-Fi causes a related mix-up. Wi-Fi connects a phone or laptop to your local network. The internet service that network uses is a separate thing. A softphone on Wi-Fi with no internet behind it can still reach anything that network routes to, such as a phone system on site or a private link to another office. It can't reach a service that's only available over the internet.
\nHow much connection a call needs is its own question. We answer it in how much bandwidth a VoIP call uses, and we compare access types in what type of internet connection you need for VoIP.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":20},{"id":"32cd37bd-e534-42f7-a861-9095e8207b6d","sectionKey":"a_provider_connection_that_skips_the_public_internet","sectionType":"markdown_section","heading":"A provider connection that skips the public internet","introMarkdown":"Atlantech Online described two ways to connect an office in a [2016 article on connections for VoIP](https://care.atlantech.net/news/posts/byob-vs-dedicated-connection-which-is-best-for-voip). In the first, a business buys internet from one company and phone service from another. A call leaves the office on the internet connection, crosses the internet to the voice provider's switch, and goes from there to the public telephone network. In the second, the office's connection is on the same network as the voice switch.\n\nAtlantech wrote in 2016 that calls on its network didn't have to travel across the internet to reach the phone service. The article said its voice switch was in its own data center and customer connections were on its network, so the packets went from the office to the switch. A call like that is still VoIP. It travels as IP packets the whole way to the switch. It just never crosses the public internet on that stretch.\n\nWhat changes is who runs the path. On the public internet, a call crosses networks that neither you nor your voice provider operates. On a connection to the voice provider's own network, one company runs the equipment at both ends and, as the article puts it, can configure that equipment to put voice traffic first.\n\nThis arrangement covers the office and no further. Someone working from home on another company's internet service reaches the phone service over that connection. And the business still pays for a data connection to the building, even though the calls don't use the public internet to get to the switch.","introHtml":"Atlantech Online described two ways to connect an office in a 2016 article on connections for VoIP. In the first, a business buys internet from one company and phone service from another. A call leaves the office on the internet connection, crosses the internet to the voice provider's switch, and goes from there to the public telephone network. In the second, the office's connection is on the same network as the voice switch.
\nAtlantech wrote in 2016 that calls on its network didn't have to travel across the internet to reach the phone service. The article said its voice switch was in its own data center and customer connections were on its network, so the packets went from the office to the switch. A call like that is still VoIP. It travels as IP packets the whole way to the switch. It just never crosses the public internet on that stretch.
\nWhat changes is who runs the path. On the public internet, a call crosses networks that neither you nor your voice provider operates. On a connection to the voice provider's own network, one company runs the equipment at both ends and, as the article puts it, can configure that equipment to put voice traffic first.
\nThis arrangement covers the office and no further. Someone working from home on another company's internet service reaches the phone service over that connection. And the business still pays for a data connection to the building, even though the calls don't use the public internet to get to the switch.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":30},{"id":"1f487fd5-bc17-41a7-bc75-3eb7321a00e3","sectionKey":"calls_that_never_leave_the_building","sectionType":"markdown_section","heading":"Calls that never leave the building","introMarkdown":"Suppose a company runs its phone system on a server in its own office, and two employees call each other by extension. Both phones and the phone system sit on the office network, so that call needs no outside connection. It keeps working if the internet service fails, as long as the local network and the phone system have power.\n\nOutside calls are different. They need a route to the public telephone network, such as a trunk from a carrier. If that trunk rides the internet connection that failed, outside calling stops while internal calls carry on.\n\nHosted service reverses the picture. The system that connects calls lives at the provider, so two desk phones on the same office network have to reach the provider before one can ring the other. If the only path to the provider is the connection that failed, those phones stop, even for a call across the hall. They keep working when a second connection is up and the network is set up to route them over it. Equipment on site that takes over is another approach.\n\nMicrosoft documents the on-site approach for Teams Phone with Direct Routing. Its [Survivable Branch Appliance guidance](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-survivable-branch-appliance) describes a branch that loses internet while its internal network stays up, along with the session border controller that connects the branch to the telephone network. With the appliance in place, the Teams client switches to it, and people can keep making and receiving outside calls.\n\nThe conditions are specific. The appliance comes through the session border controller's vendor, and the controller has to be configured for media bypass. The supported clients Microsoft lists are the Teams desktop apps for Windows and macOS and Teams Phones. The desktop apps have to run on a physical machine, and web clients and virtual machines aren't supported. Microsoft says location information isn't shared on emergency calls in this mode. Its scenario assumes users can still reach the session border controller that provides the telephone connection, so that connection can't depend on the internet link that failed.","introHtml":"Suppose a company runs its phone system on a server in its own office, and two employees call each other by extension. Both phones and the phone system sit on the office network, so that call needs no outside connection. It keeps working if the internet service fails, as long as the local network and the phone system have power.
\nOutside calls are different. They need a route to the public telephone network, such as a trunk from a carrier. If that trunk rides the internet connection that failed, outside calling stops while internal calls carry on.
\nHosted service reverses the picture. The system that connects calls lives at the provider, so two desk phones on the same office network have to reach the provider before one can ring the other. If the only path to the provider is the connection that failed, those phones stop, even for a call across the hall. They keep working when a second connection is up and the network is set up to route them over it. Equipment on site that takes over is another approach.
\nMicrosoft documents the on-site approach for Teams Phone with Direct Routing. Its Survivable Branch Appliance guidance describes a branch that loses internet while its internal network stays up, along with the session border controller that connects the branch to the telephone network. With the appliance in place, the Teams client switches to it, and people can keep making and receiving outside calls.
\nThe conditions are specific. The appliance comes through the session border controller's vendor, and the controller has to be configured for media bypass. The supported clients Microsoft lists are the Teams desktop apps for Windows and macOS and Teams Phones. The desktop apps have to run on a physical machine, and web clients and virtual machines aren't supported. Microsoft says location information isn't shared on emergency calls in this mode. Its scenario assumes users can still reach the session border controller that provides the telephone connection, so that connection can't depend on the internet link that failed.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":40},{"id":"7982b53f-d763-45e7-9fd7-dd564dab5932","sectionKey":"what_stops_when_the_connection_or_the_power_fails","sectionType":"markdown_section","heading":"What stops when the connection or the power fails","introMarkdown":"When the office internet connection is the only path to a hosted service, an outage takes the desk phones offline until the connection returns. A mobile app gives the service a second path. Atlantech's [UCaaS service](https://www.atlantech.net/solutions/voice/unified-communications) lists a mobile app for Android and iOS for taking business calls anywhere. Suppose an employee has an app like that, and their mobile phone still has working cellular service. The app reaches the hosted phone system over the carrier's data network, which doesn't run through the office. That employee keeps taking business calls while the desk phones wait for the connection.\n\nPower is the other dependency. The FCC's guide warns that some VoIP services don't work during power outages and that the provider may not offer backup power. A desk phone, the network switch it plugs into and the router all need electricity. A call fails if any one of them is dark.\n\nEmergency calling is where these limits carry the most weight. A VoIP phone that can't reach its service can't reach 911 through that service either. We cover what to plan for in whether you can dial 911 from a VoIP phone.","introHtml":"When the office internet connection is the only path to a hosted service, an outage takes the desk phones offline until the connection returns. A mobile app gives the service a second path. Atlantech's UCaaS service lists a mobile app for Android and iOS for taking business calls anywhere. Suppose an employee has an app like that, and their mobile phone still has working cellular service. The app reaches the hosted phone system over the carrier's data network, which doesn't run through the office. That employee keeps taking business calls while the desk phones wait for the connection.
\nPower is the other dependency. The FCC's guide warns that some VoIP services don't work during power outages and that the provider may not offer backup power. A desk phone, the network switch it plugs into and the router all need electricity. A call fails if any one of them is dark.
\nEmergency calling is where these limits carry the most weight. A VoIP phone that can't reach its service can't reach 911 through that service either. We cover what to plan for in whether you can dial 911 from a VoIP phone.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":50}],"citations":[{"title":"47 CFR 9.3, Definitions: Interconnected VoIP service","url":"https://www.ecfr.gov/current/title-47/chapter-I/subchapter-B/part-9/subpart-A/section-9.3","excerpt":"An interconnected Voice over Internet Protocol (VoIP) service is a service that: (i) Enables real-time, two-way voice communications; (ii) Requires a broadband connection from the user's location; (iii) Requires internet protocol-compatible customer premises equipment (CPE); and (iv) Permits users generally to receive calls that originate on the public switched telephone network and to terminate calls to the public switched telephone network.","quoteText":null,"sourceRole":"INDEPENDENT","verifiedAt":"2026-09-14T00:00:00","supportsText":"An interconnected VoIP service enables real-time, two-way voice communications, requires a broadband connection from the user's location, requires IP-compatible customer premises equipment, and permits users generally to receive calls originating on, and terminate calls to, the public switched telep","domain":"ecfr.gov","publisherName":"Electronic Code of Federal Regulations (eCFR), Office of the Federal Register"},{"title":"47 CFR 9.11: E911 Service (interconnected VoIP)","url":"https://www.ecfr.gov/current/title-47/section-9.11","excerpt":"Each interconnected VoIP service provider shall specifically advise every subscriber, both new and existing, prominently and in plain language, of the circumstances under which E911 service may not be available... Such circumstances include, but are not limited to, relocation of the end user's IP-compatible CPE, use by the end user of a non-native telephone number, broadband connection failure, loss of electrical power, and delays that may occur in making a dispatchable location available.","quoteText":null,"sourceRole":"INDEPENDENT","verifiedAt":"2026-09-14T00:00:00","supportsText":"Providers must advise every subscriber in plain language of the circumstances in which E911 may be unavailable or limited, including broadband connection failure and loss of electrical power, must record each subscriber's acknowledgement, and must meet stated location requirements for non-fixed inte","domain":"ecfr.gov","publisherName":"Electronic Code of Federal Regulations (National Archives / GPO)"},{"title":"Understanding Voice over Internet Protocol (VoIP)","url":"https://www.cisa.gov/sites/default/files/publications/understanding_voip.pdf","excerpt":"VoIP requires a connection to the Internet through an ISP, a VoIP service to extend the reach to traditional landlines, and VoIP software to actually place calls. Plain Old Telephone Service (POTS) requires none of these prerequisites... During a typical power outage, VoIP becomes unavailable because VoIP devices (computers, routers, adapters) usually rely on a power source to function... 911 services are not guaranteed with a basic (VoIP to VoIP) setup.","quoteText":null,"sourceRole":"INDEPENDENT","verifiedAt":"2026-09-14T00:00:00","supportsText":"VoIP requires a connection to the internet through an ISP plus a VoIP service to reach traditional landlines; VoIP becomes unavailable during a typical power outage and a UPS is advised; 911 is not guaranteed on a basic VoIP-to-VoIP setup; DSL internet uses existing telephone wiring","domain":"cisa.gov","publisherName":"Cybersecurity and Infrastructure Security Agency (US-CERT)"},{"title":"RFC 3261: SIP: Session Initiation Protocol","url":"https://www.rfc-editor.org/rfc/rfc3261.txt","excerpt":"SIP is an agile, general-purpose tool for creating, modifying, and terminating sessions that works independently of underlying transport protocols and without dependency on the type of session that is being established... SIP runs on top of several different transport protocols.","quoteText":null,"sourceRole":"INDEPENDENT","verifiedAt":"2026-09-14T00:00:00","supportsText":"SIP is an application-layer control (signaling) protocol for creating, modifying, and terminating multimedia sessions that runs on top of several different transport protocols and works independently of the underlying transport","domain":"rfc-editor.org","publisherName":"IETF"},{"title":"RFC 4364: BGP/MPLS IP Virtual Private Networks (VPNs)","url":"https://www.rfc-editor.org/rfc/rfc4364.txt","excerpt":"This document describes a method by which a Service Provider may use an IP backbone to provide IP Virtual Private Networks (VPNs) for its customers... Data packets are tunneled through the backbone, so that the core routers do not need to know the VPN routes.","quoteText":null,"sourceRole":"INDEPENDENT","verifiedAt":"2026-09-14T00:00:00","supportsText":"A service provider can use an IP backbone to deliver IP VPNs to customers, with customer data packets tunneled through the backbone so core routers do not need the VPN routes, which is the private-IP transport option that carries voice without public internet transit","domain":"rfc-editor.org","publisherName":"IETF"},{"title":"RFC 6716: Definition of the Opus Audio Codec","url":"https://www.rfc-editor.org/rfc/rfc6716.txt","excerpt":"Opus supports all bitrates from 6 kbit/s to 510 kbit/s... For a frame size of 20 ms, these are the bitrate \"sweet spots\" for Opus in various configurations: o 8-12 kbit/s for NB speech, o 16-20 kbit/s for WB speech, o 28-40 kbit/s for FB speech.","quoteText":null,"sourceRole":"INDEPENDENT","verifiedAt":"2026-09-14T00:00:00","supportsText":"Opus supports all bitrates from 6 kbit/s to 510 kbit/s, and at a 20 ms frame size the stated bitrate sweet spot for wideband speech is 16 to 20 kbit/s","domain":"rfc-editor.org","publisherName":"IETF"},{"title":"ITU-T Recommendation G.114 (05/2003): One-way transmission time","url":"https://www.itu.int/rec/T-REC-G.114-200305-I/en","excerpt":"Although a few applications may be slightly affected by end-to-end (i.e., \"mouth-to-ear\" in the case of speech) delays of less than 150 ms, if delays can be kept below this figure, most applications, both speech and non-speech, will experience essentially transparent interactivity... While it is recommended that a one-way delay of 400 ms should not be exceeded for general network planning...","quoteText":null,"sourceRole":"INDEPENDENT","verifiedAt":"2026-09-14T00:00:00","supportsText":"400 ms is the upper bound for one-way delay in general network planning, and keeping mouth-to-ear delay below 150 ms leaves most applications with essentially transparent interactivity","domain":"itu.int","publisherName":"International Telecommunication Union (ITU-T)"},{"title":"Modify Bandwidth Consumption Calculation for Voice Calls","url":"https://www.cisco.com/c/en/us/support/docs/voice/voice-quality/7934-bwidth-consume.html","excerpt":"Total packet size = (L2 header: MP or FRF.12 or Ethernet) + (IP/UDP/RTP header) + (voice payload size)... Bandwidth = total packet size * PPS. G.711: 64 Kbps codec bit rate, 160 bytes voice payload, 50 PPS, 87.2 Kbps bandwidth (Ethernet). G.729: 8 Kbps, 20 bytes, 50 PPS, 31.2 Kbps.","quoteText":null,"sourceRole":"SUPPORTING","verifiedAt":"2026-09-14T00:00:00","supportsText":"Vendor engineering document giving the per-call bandwidth formula (L2 header + 40-byte IP/UDP/RTP header + voice payload, times packets per second) and the Ethernet results used in this answer: G.711 at 87.2 kbps and G.729 at 31.2 kbps, both at 50 packets per second with a 20 ms payload","domain":"cisco.com","publisherName":"Cisco"},{"title":"Survivable Branch Appliance (SBA) for Direct Routing","url":"https://learn.microsoft.com/en-us/microsoftteams/direct-routing-survivable-branch-appliance","excerpt":"During an internet outage, the Teams client switches to the SBA automatically, and ongoing calls continue with no interruptions... Making PSTN calls through the local SBA/SBC with media flowing through the SBC... VoIP calls between local users. If both users are registered behind the same SBA, a VoIP call can be initiated... Sharing location information during an emergency call (E911). Users can still make emergency call but location information won't be shared.","quoteText":null,"sourceRole":"SUPPORTING","verifiedAt":"2026-09-14T00:00:00","supportsText":"Vendor product documentation: during an internet outage the Teams client switches automatically to a local Survivable Branch Appliance, ongoing calls continue, PSTN calls can be placed and received through the local SBC, two users behind the same appliance can call each other over VoIP, and emergenc","domain":"learn.microsoft.com","publisherName":"Microsoft Learn"},{"title":"Setting up call forwarding during an internet outage","url":"https://support.ringcentral.com/article-v2/setting-up-call-forwarding-during-an-internet-outage.html?brand=RingCentral&product=RingEX&language=en_US","excerpt":"If your deskphone is offline due to an internet outage, incoming calls can automatically be forwarded to another extension or external number.","quoteText":null,"sourceRole":"SUPPORTING","verifiedAt":"2026-09-14T00:00:00","supportsText":"Vendor product documentation showing provider-side forwarding: when a deskphone is offline because of an internet outage, incoming calls can be forwarded automatically to another extension or an external number","domain":"support.ringcentral.com","publisherName":"RingCentral (vendor product documentation)"},{"title":"What Is a PBX Phone System? Complete Guide to Private Branch Exchange","url":"https://www.onsip.com/voip-resources/voip-fundamentals/what-is-pbx-phone-system","excerpt":"Instead of copper wiring, phones connect to the PBX server over your office's Local Area Network (LAN)... Free internal calling: Employees can call each other's extensions without consuming outside lines or incurring charges.","quoteText":null,"sourceRole":"SUPPORTING","verifiedAt":"2026-09-14T00:00:00","supportsText":"Vendor resource page describing on-premises IP PBX operation: phones connect to the PBX server over the office LAN, and employees call each other's extensions without consuming outside lines or incurring charges","domain":"onsip.com","publisherName":"OnSIP"},{"title":"How Much Data Does VoIP Use? Tips To Save Bandwidth","url":"https://www.nextiva.com/blog/voip-data-usage.html","excerpt":"VoIP typically requires 80-100 kbps of bandwidth per concurrent call... Codec / 10-Minute Call / 1-Hour Call. G.711 102 MB 613 MB. G.729 36 MB 219 MB.","quoteText":null,"sourceRole":"SUPPORTING","verifiedAt":"2026-09-14T00:00:00","supportsText":"Cited as the origin of the data figure this answer corrects: the page publishes 102 MB for a ten-minute G.711 call and 613 MB for an hour, alongside an 80 to 100 kbps per-call bandwidth range; the megabyte figures do not follow from that bitrate","domain":"nextiva.com","publisherName":"Nextiva"}],"revisions":[{"revisedAt":"2026-07-18T03:26:50.582+00:00","versionLabel":"Originally published","note":"","reviewedBy":null}],"relatedAnswers":[{"id":"0ef1cfdf-0d57-4903-8eb6-b422a49ece05","slug":"what-type-of-internet-connection-do-i-need-for-voip","question":"What type of internet connection do I need for VoIP?","publishedAt":"2026-06-25T03:27:41.235","confidenceScore":90,"confidenceLabel":"High","industry":{"id":"ff619d7c-d7d7-485e-a05a-53fba07f33ed","slug":"telecommunications","label":"Telecommunications","description":"Business voice, fiber, UCaaS, and network services"},"topic":{"slug":"voip","label":"VoIP","description":"Voice over IP for business: how it works, what it requires, and how it compares to traditional phone service.","schemaKind":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"snippet":"VoIP needs no particular connection type. It needs an IP connection to your voice provider with room in each direction for the simultaneous calls you plan to support, plus your other traffic. One G.711 call takes about 87 to 100 kbps each way. Also decide whether calls cross the public internet or the provider's network.","url":"/q/what-type-of-internet-connection-do-i-need-for-voip"},{"id":"f3429824-6f34-416e-9422-272837f4e0c9","slug":"how-much-bandwidth-does-a-voip-call-use","question":"How much bandwidth does a VoIP call use?","publishedAt":"2026-05-09T03:24:27.71","confidenceScore":84,"confidenceLabel":"High","industry":{"id":"ff619d7c-d7d7-485e-a05a-53fba07f33ed","slug":"telecommunications","label":"Telecommunications","description":"Business voice, fiber, UCaaS, and network services"},"topic":{"slug":"voip","label":"VoIP","description":"Voice over IP for business: how it works, what it requires, and how it compares to traditional phone service.","schemaKind":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"snippet":"Cisco's calculation puts a G.711 VoIP call at 87.2 kbps in each direction and a G.729 call at 31.2 kbps, counting IP, UDP, RTP and Ethernet headers with 20 milliseconds of speech per packet. The figure changes with codec, packet size and link type. Multiply it by simultaneous calls and compare it with upload and download separately.","url":"/q/how-much-bandwidth-does-a-voip-call-use"},{"id":"2bc2d203-d1bf-4685-91a1-cd586dddf234","slug":"do-i-need-a-phone-line-for-voip","question":"Do I need a phone line for VoIP?","publishedAt":"2026-05-02T03:33:04.199","confidenceScore":92,"confidenceLabel":"High","industry":{"id":"ff619d7c-d7d7-485e-a05a-53fba07f33ed","slug":"telecommunications","label":"Telecommunications","description":"Business voice, fiber, UCaaS, and network services"},"topic":{"slug":"voip","label":"VoIP","description":"Voice over IP for business: how it works, what it requires, and how it compares to traditional phone service.","schemaKind":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"snippet":"No. VoIP needs a data connection and a compatible device or app, not a traditional analog phone line. Calling ordinary phone numbers also takes a service connected to the public telephone network. Check your internet, number and connected devices before cancelling the old line.","url":"/q/do-i-need-a-phone-line-for-voip"},{"id":"09cc8e4a-38e6-4d0f-af1c-342b8e394204","slug":"what-is-voip","question":"What is VoIP?","publishedAt":"2026-04-23T03:09:30.888","confidenceScore":92,"confidenceLabel":"High","industry":{"id":"ff619d7c-d7d7-485e-a05a-53fba07f33ed","slug":"telecommunications","label":"Telecommunications","description":"Business voice, fiber, UCaaS, and network services"},"topic":{"slug":"voip","label":"VoIP","description":"Voice over IP for business: how it works, what it requires, and how it compares to traditional phone service.","schemaKind":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"snippet":"VoIP, voice over Internet Protocol, is the group of technologies that carries voice calls as data over a network using internet protocols. It describes how a call travels, not a product. It is sold in several forms, including hosted phone systems, SIP trunks and calling inside collaboration apps.","url":"/q/what-is-voip"}],"contributorStats":{"verifiedAnswers":149,"openDisputes":0},"schemaJson":{"@context":"https://schema.org","@type":"Question","name":"Does VoIP require an internet connection?","text":"Does VoIP require an internet connection?","url":"https://www.answerstack.io/q/does-voip-require-an-internet-connection","answerCount":1,"datePublished":"2026-07-03T03:26:50.582","about":[{"@type":"Thing","name":"VoIP"},{"@type":"Thing","name":"Telecommunications"}],"acceptedAnswer":{"@type":"Answer","text":"Not always. VoIP requires an IP network path between your phone and the system that handles its calls, and that path can be public or private. A call can cross the internet, run over a private connection to your provider, or stay between two phones inside one building. Which of those your calls use depends on how the service is set up. To call ordinary phone numbers, the call also has to reach a service connected to the public telephone network.","url":"https://www.answerstack.io/q/does-voip-require-an-internet-connection","upvoteCount":0,"datePublished":"2026-07-03T03:26:50.582","dateModified":"2026-09-14T00:00:00","citation":[{"@type":"CreativeWork","name":"47 CFR 9.3, Definitions: Interconnected VoIP service","url":"https://www.ecfr.gov/current/title-47/chapter-I/subchapter-B/part-9/subpart-A/section-9.3"},{"@type":"CreativeWork","name":"47 CFR 9.11: E911 Service (interconnected VoIP)","url":"https://www.ecfr.gov/current/title-47/section-9.11"},{"@type":"CreativeWork","name":"Understanding Voice over Internet Protocol (VoIP)","url":"https://www.cisa.gov/sites/default/files/publications/understanding_voip.pdf"},{"@type":"CreativeWork","name":"RFC 3261: SIP: Session Initiation Protocol","url":"https://www.rfc-editor.org/rfc/rfc3261.txt"},{"@type":"CreativeWork","name":"RFC 4364: BGP/MPLS IP Virtual Private Networks (VPNs)","url":"https://www.rfc-editor.org/rfc/rfc4364.txt"},{"@type":"CreativeWork","name":"RFC 6716: Definition of the Opus Audio Codec","url":"https://www.rfc-editor.org/rfc/rfc6716.txt"},{"@type":"CreativeWork","name":"ITU-T Recommendation G.114 (05/2003): One-way transmission time","url":"https://www.itu.int/rec/T-REC-G.114-200305-I/en"},{"@type":"CreativeWork","name":"Modify Bandwidth Consumption Calculation for Voice Calls","url":"https://www.cisco.com/c/en/us/support/docs/voice/voice-quality/7934-bwidth-consume.html"},{"@type":"CreativeWork","name":"Survivable Branch Appliance (SBA) for Direct Routing","url":"https://learn.microsoft.com/en-us/microsoftteams/direct-routing-survivable-branch-appliance"},{"@type":"CreativeWork","name":"Setting up call forwarding during an internet outage","url":"https://support.ringcentral.com/article-v2/setting-up-call-forwarding-during-an-internet-outage.html?brand=RingCentral&product=RingEX&language=en_US"},{"@type":"CreativeWork","name":"What Is a PBX Phone System? 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