Voice over IP : Internet Telephony | Knowledgebase UK [Contact](# "Contact") ![](/web-assets/f/290788/40x40/d98615a3ea/nfon-sales-contact.svg) Sales & General * [Talk to Sales](tel:+443303838000) * [Write to us](/gb/request-information) Search * [![Products](https://a.storyblok.com/f/290788/40x40/539cd331b9/nfon-products.svg) Products](#) Call & Work ![AI icon](/assets/ai_icon.webp) + [Cloud Telephony](/gb/products/cloud-telephony/) + [SIP Trunk](/gb/products/enablement/) + [Devices](/gb/products/devices) Build & Automate ![AI icon](/assets/ai_icon.webp) + [Assistants](/gb/products/ai/assistants) + [Bots](/gb/products/ai/bots) + [AI Agent Studio](/gb/products/ai/agent-studio) Engage & Support ![AI icon](/assets/ai_icon.webp) + [Contact Center](/gb/products/customer-contact/) Integrations & Add ons + [Integrations & Add ons](/gb/integrations/) * [![Solutions](https://a.storyblok.com/f/290788/40x40/da156cbbb8/nfon-solutions-industries.svg) Solutions](#) Industries + [Health & Wellness](/gb/solutions/health-wellness) + [Retail & E-Commerce](/gb/solutions/retail) + [Finance & Legal](/gb/solutions/finance-insurance) + [Travel & Hospitality](/gb/solutions/hospitality) + [Public Sector](/gb/solutions/public-sector) + [Energy](/gb/solutions/energy) Success stories + [Customer Stories](/gb/customer-stories/) * [![Partnerships](https://a.storyblok.com/f/290788/36x36/7bd105c67d/nfon-partner.svg) Partnerships](#) Partner with NFON + [Partner](/gb/partner/become-partner) + [NGAGE](/gb/partner/partner-programme) Partner Portal + [Partner Portal](https://partners.nfon.com/) * [![Help Center](https://a.storyblok.com/f/290788/40x40/d01fbb4f30/help-nfon.svg) Help Center](/gb/help-centre) * [Login](https://start.cloudya.com/ "Login") * United Kingdom + [International](/en) + [Deutschland](/de) + [España](/es) + [France](/fr) + [Italia](/it) + [Österreich](/at) + [Polska](/pl) + [Portugal](/pt) + [United Kingdom](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip) [![NFON Logo](/assets/logo-nfon.svg)](/gb/ "NFON Home") * [Products](#) ![](/web-assets/f/290788/36x36/a9f3ceed6f/nfon-call-work.svg) Call & Work ![AI icon](/assets/ai_icon.webp) Seamless communication ![](/web-assets/f/290788/36x36/d03c61cf40/nfon-build-automate.svg) Build & Automate ![AI icon](/assets/ai_icon.webp) AI Automation ![](/web-assets/f/290788/36x36/106823b73b/nfon-engage-support.svg) Engage & Support ![AI icon](/assets/ai_icon.webp) Omnichannel support ![](/web-assets/f/290788/36x36/50b60f5411/nfon-integrations-add-ons.svg) Integrations & Add ons Connect Teams & CRMs + [![](/images/products-call-work-cloudteleophny-navbar-int_Fjf8b.webp) ### Cloud Telephony ![AI icon](/assets/ai_icon.webp) Seamless cloud telephony for every device. High-fidelity audio with European-grade security.](/gb/products/cloud-telephony/) + [![](/images/products-call-work-siptrunk-navbar-int_ZH5NzW.webp) ### SIP Trunk Secure cloud connectivity for your existing hardware. Scales instantly with your business.](/gb/products/enablement/) + [![](/images/products-call-work-devices-navbar-int_Z2dP6.webp) ### Devices Professional telephones and hardware designed for clear calls and all-day comfort.](/gb/products/devices) + [![](/images/products-build-automate-assistants-navbar-int_2ghUIJ.webp) ### Assistants ![AI icon](/assets/ai_icon.webp) Pre-configured, plug-and-play digital roles like FrontDesk and Workdesk. Ready to deploy instantly with zero coding required.](/gb/products/ai/assistants) + [![](/images/products-build-automate-bots-navbar-int_Z1p57Vm.webp) ### Bots ![AI icon](/assets/ai_icon.webp) Prompt-driven, multi-channel conversational experiences. Automate custom customer journeys across Web Chat, Voice, and Livechat.](/gb/products/ai/bots) + [![A chatbot creation interface is shown with a readiness message, build report, agent prompt details, and created tools list, over a gradient background.](/images/products-build-agent-studio-navbar-int_Z1Y88dE.webp) ### AI Agent Studio ![AI icon](/assets/ai_icon.webp) Simply turn your ideas into AI agents for your business. Describe the task, create a working agent, then optimize it in one workspace.](/gb/products/ai/agent-studio) + [![](/images/products-engage-support-navbar-int_1xyFBE.webp) ### Contact Center ![AI icon](/assets/ai_icon.webp) Omnichannel customer service for modern teams. Manage conversations, automation, AI assistance, and customer context.](/gb/products/customer-contact/) + [![](/images/products-integrations-addons-navbar-int_Z1Ka5ea.webp) ### Integrations & Add ons Expand your capabilities and natively connect your everyday business to keep all workflows unified.](/gb/integrations/) * [Solutions](#) ![](/web-assets/f/290788/40x40/da156cbbb8/nfon-solutions-industries.svg) Industries Tailored solutions ![](/web-assets/f/290788/40x40/155f2a989d/nfon-success.svg) Success stories 54,000+ trust us + [![](/images/solutions-health-wellness-navbar-int_Z15q3kJ.webp) ### Health & Wellness Secure communication for better patient experiences and care delivery.](/gb/solutions/health-wellness) + [![](/images/solutions-retail-ecommerce-navbar-int_zUgjw.webp) ### Retail & E-Commerce Connected communication for modern retail and customer engagement.](/gb/solutions/retail) + [![](/images/solutions-finance-legal-navbar-int_1Dy5Ax.webp) ### Finance & Legal Trusted communication for regulated and security-conscious organizations.](/gb/solutions/finance-insurance) + [![](/images/solutions-hospitality-travel-navbar-int_17WoBe.webp) ### Travel & Hospitality Seamless communication for exceptional guest experiences and service.](/gb/solutions/hospitality) + [![](/images/solutions-publicsector-navbar-int_YyABB.webp) ### Public Sector Reliable communication for responsive public services and citizen support.](/gb/solutions/public-sector) + [![](/images/solutions-energy-navbar_FDoix.webp) ### Energy Reliable communication for responsive customer service, even during outages and peak demand.](/gb/solutions/energy) + [![](/images/solutions-costumerstroy-navbar-int_Z1MdOsM.webp) ### Customer Stories Real-world impact across every industry. Explore how we solve complex communication challenges for Europe’s leading brands.](/gb/customer-stories/) * [Partnerships](#) ![](/web-assets/f/290788/36x36/7bd105c67d/nfon-partner.svg) Partner with NFON Join the NFON network ![](/web-assets/f/290788/36x36/8c5c9a9c78/nfon-partner-portal.svg) Partner Portal Existing partner login + [![](/images/partnerships-partner-navbar-int_ZHYGKx.webp) ### Partner From onboarding to co-branded marketing, we provide the tools you need to win.](/gb/partner/become-partner) + [![](/images/partnerships-ngage-navbar-int_Zs3yY9.webp) ### NGAGE Discover our tiered rewards system designed to help you scale your business and revenue.](/gb/partner/partner-programme) + [![](/images/partnerships-partnerportal-navbar-int_2ki451.webp) ### Partner Portal Access partner tools, deal registration, training resources, and program benefits in one place.](https://partners.nfon.com/) * [Help Center](/gb/help-centre) * Search * [Login](https://start.cloudya.com/ "Login") * gb + [International](/en) + [Deutschland](/de) + [España](/es) + [France](/fr) + [Italia](/it) + [Österreich](/at) + [Polska](/pl) + [Portugal](/pt) + [United Kingdom](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip) * [Contact](#) [Contact](# "Contact") + ![](/web-assets/f/290788/40x40/d98615a3ea/nfon-sales-contact.svg) Sales & General Get in touch with us. ![](/images/getstarted-talktosales-navbar-int_ZMspQ4.webp) ### Talk to Sales Get a free consultation to see how NFON products can meet your needs. [+44 330 383 8000](tel:+443303838000 "+44 330 383 8000") ![](/images/getstarted-writetous-navbar-int_ZY7MOf.webp) ### Write to us Fill out our request form. Our experts will respond as soon as possible. [Write to us](/gb/request-information "Write to us") ### Voice over Internet Protocol (VoIP) [What is PSTN?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip#section-3) [How does VoIP work?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip#section-4) [Top VoIP benefits for businesses](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip#section-5) [Can you use VoIP to call non-VoIP users?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip#section-6) [How secure is VoIP?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip#section-7) [Which devices do you need in order to migrate to VoIP?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip#section-8) [voip](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip#section-9) [What are the top VoIP use cases for business?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip#section-10) [What are the benefits of VoIP?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip#section-11) [How can I deploy VoIP in my business?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip#section-12) # Voice over Internet Protocol (VoIP) **What is VoIP?** The **Voice over Internet Protocol,** also called IP telephony, is a method of communication for making calls over a broadband Internet connection as an alternative to regular calls made over an analogue phone using the [PSTN](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/pstn). These VoIP calls can happen entirely over the Internet but where required, gateways also link to the PSTN. This means that VoIP users can still connect to anyone with a telephone number including local, mobile, and international numbers. VoIP services can be accessed from a computer with a so-called [softphone,](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/softphones) from an IP phone, from a smartphone or from a conventional landline phone that is connected to a VoIP adapter. ### What is PSTN? PSTN stands for Public Switched Telephone Network and is generally known as the traditional phone network. It has been connecting people since the late 19th century, at first over copper telephone lines and later using fibre optic cables, satellites, and undersea cables. All of these are interconnected by switching centres which establish a dedicated connection – or circuit – between callers. Voice signals can then travel over this circuit. When the caller speaks into his handset, the caller’s phone translates the sound waves into electrical signals. These are transmitted over the PSTN (converted to optical signals for part of the way, so they can travel via fibre optic cables), and the phone at the other end of the line then translates the received signals back into sound. The arrival of **Voice over IP (VoIP)** technology – essentially, transmitting voice calls over the Internet rather than the PSTN – challenged traditional telephony and fundamentally changed how people communicate. ### How does VoIP work? In order to make and process VoIP phone calls, and to benefit from additional features that are possible with IP telephony such as [conferencing](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/conference-function), [call recording](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/how-your-business-can-benefit-from-call-recording) or [Computer Telephony Integration (CTI),](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/cti) businesses need a dedicated VoIP solution. **Switching data packets over VoIP** The VoIP technology’s key function is to convert the caller’s voice into a digital signal that can then be transmitted over the Internet. 1. **Audio is digitised** As the caller speaks into the microphone or handset, the sound waves are digitised and then broken up into pieces called “packets”, each with a unique label. 2. **Data is transmitted securely over the Internet** These data packets can travel securely over the Internet to reach the recipient. 3. **Data is decoded and reassembled** At their destination, they are reconstructed and converted back to sound. This packet switching is more efficient than the traditional circuit switching because it doesn’t rely on a fixed physical path between source and destination, which means several separate calls can securely share the available bandwidth. ### How it works ![](https://a.storyblok.com/f/290788/bfa1df8df5/voice_over_ip_telefonanlage_nfon.png) ### Top VoIP benefits for businesses 1. **Free internal calls** With a cloud telephony solution, you can call anyone in your organisation completely free of charge, including colleagues in different offices and branches in different countries. There’s no need for expensive equipment or service provider contracts. 2. **Cheaper external calls** Typically, VoIP telephony is considerably more cost-efficient than traditional landline and mobile telephony. This is because VoIP transports voice data over the Internet. This is a contrast to traditional calls over the PSTN network, which require a dedicated connection for the entire call duration. Compared to conventional phone systems, a VoIP platform can therefore reduce the cost of calling external mobile phones as well as landlines. 3. **Less hardware** Given that the best VoIP solutions are hosted in the cloud, they provide the full range of business telephony features without having to install costly physical telecommunications infrastructures. This saves costs while also simplifying and speeding up deployment. 4. **Easy mobile working** With a dedicated VoIP app – such as the [Cloudya app from NFON](/gb/en/products/cloudya) – employees can also access all telephony features of the cloud telephone system on their mobile device. Each user has a single number for landline and mobile, which makes it easier for colleagues and customers to reach them. 5. **Pre-integration with Unified Communications tools** Integrations add even more functionality for more efficient business processes. As an example, NFON’s cloud telephony system integrates with [Unified Communications tools](t3://page?uid=1302) such as Microsoft Teams. This integration enables users to make phone calls within the familiar Teams environment where they also access other UC functions, and to benefit from lower costs. ### Can you use VoIP to call non-VoIP users? Yes, in the majority of cases, VoIP users can call non-VoIP mobile phones or landlines, which means you can get all the simplicity, flexibility and cost savings of VoIP, whoever you’re calling. VoIP solutions use something called a VoIP gateway to connect with regular mobile phones and landlines via the PSTN network. The VoIP gateway also converts calls from traditional phones into IP, so anyone in the world can call you on your VoIP phone. ### How secure is VoIP? Reliable VoIP solutions are hosted in highly secure data centres and use proven technologies such as encryption to protect your voice data. NFON’s VoIP solution for example is hosted in geo-redundant data centres. The fact that our solution is highly secure and highly available has helped us achieve compliance with EU Electronic Communications legislation. The data centres where our solution is hosted are also fully compliant with ISO/IEC 27001 Information Security Management standards, gaining the trust of our clients and providing them with complete peace of mind. ### Which devices do you need in order to migrate to VoIP? One of the main advantages of VoIP is that is offers multiple device integration. This allows users, for instance, to also have their office extension on their mobile phone, giving them complete freedom of communication, no matter whether they are working remotely or in the office. **There are four main ways in which your current phone system can be migrated to VoIP.** 1. **Make and receive VoIP calls over a PC or laptop** A laptop or a PC can easily be converted into a VoIP enabled device and the user can adapt the PC or laptop to his needs using their chosen headset. With instant messaging, emails and video calling also taking place on the computer this means the user can access all communication channels in one place. As an example, NFON’s Cloudya lets you make calls directly from your PC or laptop, without the need for a separate desk phone. 2. **Use a VoIP phone** VoIP phones such as IP and SIP (Session Initiation Protocol) telephones typically have Ethernet connections and can be plugged directly into a modem or router. SIP phones can also handle multimedia communication such as video calls. 3. **Use your existing phone to make VoIP calls** An Analogue Telephone Adapter (ATA) allows the user to plug the phone into a modem or router, thus converting analog phone calls into IP packets. Converting existing phones into IP phones can help you maximise returns on investments in existing office equipment. 4. **Use your mobile device to make VoIP calls** Installing a dedicated app allows your smartphone to connect to your Internet telephony system. You can then be reached via a single phone number, irrespective of where you are – which makes business communication and collaboration much easier. The best Internet telephony solutions also help reduce costs by always choosing the most efficient mobile connectivity option - whether that is WLAN or mobile data on a carrier network. Above and beyond making calls, NFON’s Cloudya App , as an example, also lets users **access all the advanced PBX features** of their NFON telephony system – voicemail, blacklisting and whitelisting, call forwarding and more – from their smartphones. They can use the “meet & share” function for easy collaboration, with excellent audio and video quality. Additionally, using the app means businesses can consolidate two costly lines (and service providers) and move to a single service provider. This saves costs and simplifies supplier management. ### voip Use your existing phones to make VoIP calls If you want to use your existing telephone to make VoIP calls, you’ll need something called an Analog Telephone Adapter (ATA). This allows you to plug your phone line into a modem or router, which means that analog phone calls can be converted into IP packets and sent over the internet. Converting existing phones into IP phones can help you maximise returns on investments in existing office equipment. Use your mobile device to make VoIP calls The fourth option is to make VoIP calls on your mobile device. To do this, you’ll need to download an FMC client, which allows your phone to connect into an internet telephony system. One benefit of this approach is that everyone can contact you on a single number, whether you’re at the office or on the move. The best internet telephony solutions also help you reduce costs by choosing the most efficient mobile connectivity option - whether that’s WLAN or mobile data on a carrier network.  Another benefit of making your mobile phone an extension of your office internet telephony system is that you can consolidate two costly lines (and service providers) to a single service provider. This saves you costs and reduces supplier management admin. ### What are the top VoIP use cases for business? There are many VoIP use cases, but here are our top three: Internal calling With the NFON Cloud Telephone System, you can call anyone in your organisation completely free of charge, including colleagues in different offices and branches in different countries. There’s no need for expensive equipment or service provider contracts. External calling (to fixed and mobile phones) With the NFON Cloud Telephone System, you can reduce the cost of calling external mobile phones and landlines compared to conventional phone systems. Placing calls from your mobile device With the NFON FMC client, which is quick and easy to download, you can access all the features of our Could Telephone System on your mobile device. You will also have a single number for your landline and mobile, which makes it easier for colleagues and customer to reach you. ### What are the benefits of VoIP? The benefits of VoIP are many and varied, including support for new Unified Communications features and lower overall telephony costs. They include: Lower costs Typically, VoIP telephony is considerably more cost effective than traditional landline and mobile telephony. This is because VoIP transports voice data efficiently between callers over the internet. This is a contrast to traditional calls over the PSTN network, which require a dedicated connection for the entire call duration. Less hardware Because the best VoIP solutions are hosted in the cloud, they provide the full range of telephony features with no need for costly physical telecommunications infrastructure. This lowers costs while also simplifying and speeding up deployment. Pre-integration with Unified Communications tools The NFON Cloud Telephony System works with Unified Communications systems such as Skype for Business. This pre-integration means you can deploy video calls and other great Unified Communications features quickly and at low cost. ### Devices Voip ![](https://a.storyblok.com/f/290788/2a8829a7c1/complex_costly_tools_reduced.png) ### How can I deploy VoIP in my business? The main requirement for deploying VoIP is a good Internet connection. With NFON, everything else is hosted in the cloud on our secure servers, so you can access your new telephony platform quickly and easily, with no need for complex software installation or hardware deployment. NFON has prepared a variety of resources to help you find out more about Internet telephony and the capabilities of our [cloud telephony system.](t3://page?uid=16) ### Related Articles ### Internet telephony **What is Internet Telephony?** Internet Telephony refers to all types of telephony services (including phone calls, fax, voicemail, video calls and other forms of communication) where calls and data are sent digitally over the Internet using the [Internet Protocol (IP)](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/ip-address), rather than being transmitted over traditional analogue landlines. An example of an Internet Telephony service is [Cloudya, the Cloud Telephone System from NFON.](https://web-production.nfon.com/gb/products/cloudya) [Internet telephony](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/internet-telephony) ### IP address ### **What is an IP address?** Internet Protocol (IP) addresses are a series of numbers separated by dots. In the same way that street addresses allow us to identify their location, IP addresses allow us to identify internet-connected devices and send data to them, wherever they may be. [IP address](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/ip-address) ### Cloud The term “cloud” or “cloud computing” refers to a technology that allows applications and services to be accessed over a network such as the Internet as opposed to being run locally. Services made available by means of this technology are computing capacity, data storage space or applications such as [cloud telephone systems](https://web-production.nfon.com/gb/products/cloudya). The respective services are accessed via defined network protocols or interfaces. Many applications can be run directly from a browser. The actual IT resources for the services offered are located on a server or at a server farm **connected to the network.** [Cloud](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/cloud) [Back](#) ![NFON Logo](/assets/logo-nfon.svg) News * [Events](https://www.nfon.com/gb/news/events/) * [Press](https://www.nfon.com/gb/news/press/) Customers * [Cloudya Login](https://start.cloudya.com/auth/login) * [Admin Portal](https://admin.nfon.com/) * [NFON Status](https://status.nfon.com/) About NFON * [Corporate](https://corporate.nfon.com/en/) * [Investor Relations](https://corporate.nfon.com/en/investor-relations/ir-at-a-glance/) * [Sustainability & ESG](https://corporate.nfon.com/en/sustainability/) * [Career](https://corporate.nfon.com/en/careers/) Legal * [GTC-SLA](/gb/legal/gtc-sla) * [Legal Notice](/gb/legal/legal-notice) * [Trust Centre](https://www.nfon.com/en/trust-center/) * [Data Protection](/gb/legal/data-protection) * [Cookie Settings](javascript:onclick=UC_UI.showSecondLayer()) © 2026 - NFON | All rights reserved.