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[Write to us](/gb/request-information "Write to us") ### Telephone Connection [What is a telephone connection?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/telephone-connection#section-3) [What is an analogue telephone connection?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/telephone-connection#section-4) [What are Integrated Services Digital Network (ISDN) connections?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/telephone-connection#section-5) [What are Voice-over-IP connections?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/telephone-connection#section-6) [Why is ISDN being decommissioned?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/telephone-connection#section-7) [When is ISDN being decommissioned?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/telephone-connection#section-8) [What comes after ISDN?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/telephone-connection#section-9) [How will the decommissioning of ISDN affect my business?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/telephone-connection#section-10) [Can I migrate easily from analogue to VoIP telephony?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/telephone-connection#section-11) [Can I migrate easily from ISDN to VoIP telephony?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/telephone-connection#section-12) [Where can I learn more about VoIP telephony?](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/telephone-connection#section-13) # Telephone Connection A telephone connection is a standard part of telecommunications. In the following, we will first take a closer look at the term. ### ­ ![](https://a.storyblok.com/f/290788/9c77921768/telefonanschluss_image1.jpg) ### What is a telephone connection? A telephone connection is **any network connection** that allows users to make phone calls. There are **three main types of telephone connections**, each supported by different technologies. These are: * [Analogue telephone connections](https://www.nfon.com/en/service/knowledge-base/knowledge-base-detail/analogue-telephone-lines) * [Integrated Services Digital Network (ISDN)](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/isdn) telephone connections * [Voice-over-IP (VoIP) telephone connections](https://www.nfon.com/en/service/knowledge-base/knowledge-base-detail/voice-over-ip) ### What is an analogue telephone connection? Analogue telephone connections enable voice calls over the traditional telephone network, which is more accurately known as the [Public Switched Telephone Network (PSTN)](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/pstn). This network has limited capabilities in terms of data transfer and typically utilises copper telephone wires to connect offices and homes. One of the **main limitations of analog connections** is that they can only convey voice traffic and not other kinds of data, such as email, video, etc. ### What are Integrated Services Digital Network (ISDN) connections? Integrated Services Digital Network (ISDN) connections bring digital capabilities to the traditional analog network (PSTN). The key feature of ISDN is that it allows users to **send speech and data simultaneously over the PSTN** which is what ‘Integrated Services’ refers to. Therefore, voice connections can be used to provide other services to users, including **internet access**. It is also important to note that this technology is largely being decommissioned in favour of more modern technologies. ### What are Voice-over-IP connections? Voice-over-IP connections support telephone calling over the Internet. VoIP solutions such as the [NFON Cloud Telephony System](/gb/en/products/cloudya) enable users to have **all the functionality of a traditional phone setup**, combined with all the **advantages of the Internet**. These include: * Cost effectiveness * More [bandwidth](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/bandwidth) * Simultaneous transfer of voice and other data, such as video By enabling voice calls over the internet, VoIP is rendering ISDN and the entire PSTN network, obsolete. ### ­ ![](https://a.storyblok.com/f/290788/ec99aa5e2c/telefonanschluss_image_2.jpg) ### Why is ISDN being decommissioned? ISDN is being decommissioned for a number of reasons, mostly to do with future-proofing service providers’ operations. These are the **3 key reasons**: 1. **High operating costs** ISDN requires service providers to operate one network for voice calls and a second network for internet and data connections, duplicating their costs and workloads. 2. **Complex, expensive management and support requirements** ISDN was developed in the 1980s and relies on outdated hardware and software that is costly and time-intensive to maintain and support. 3. **Non-secure voice calls** ISDN offers no protection against increasingly sophisticated hackers, making voice calls over the PSTN vulnerable. By contrast, the best VoIP solutions, such as the NFON Cloud Telephony System, use [sophisticated encryption technology](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-encryption) to keep users’ data safe. ### When is ISDN being decommissioned? There are different dates set for different countries. In Germany, major [telephone service providers](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/telephone-provider) are **planning to decommission ISDN in 2022**. In the UK this date is set for 2025. In nearly all cases, the change is coming soon and operators need to start preparing for the switch to all-IP voice calling. ### What comes after ISDN? After ISDN, most major service providers in Europe have announced plans to **switch to all-IP networks**, most of which are already in place. Typically, the IP networks currently used for internet traffic will also be used for phone calls post ISDN. ### How will the decommissioning of ISDN affect my business? Many businesses still rely on ISDN infrastructure to support their phone systems. If that is the case at your organisation, the decommissioning of ISDN will impact you and you may benefit from **migrating to a VoIP-based telephony solution** as soon as possible. The decommissioning of ISDN shouldn’t have any negative impact on private subscribers as migrating to an all-IP voice network is the responsibility of the telephone service provider. ### Can I migrate easily from analogue to VoIP telephony? Yes, it is relatively straightforward to migrate from a traditional analogue connection to a VoIP solution. One way to do this is **to use an adapter** to convert your analogue connection into a VoIP ready connection. To do this, you will need an **Analogue Telephone Adapter (ATA)** that simply plugs into your existing connection. This approach may **offer limited functionality** compared to an all-IP solution, but it helps to maximise returns on existing telephony investments and offers a very simple, convenient path to VoIP. ### Can I migrate easily from ISDN to VoIP telephony? Yes, you can. VoIP solutions such as the [NFON Cloud Telephone System](t3://page?uid=16) make it possible to migrate **from an ISDN setup to VoIP technology**, as long as your existing equipment is VoIP ready. Although again we advocate an all-IP solution to be in line with **future developments of telephone service providers** and to make **full use of the benefits of VoIP.** ### Where can I learn more about VoIP telephony? NFON has prepared a number of FAQ documents focusing on traditional and VoIP telephony technologies and solutions. **You can find these by clicking on the links below!** **Contact us and transform your business with cloud telephony now! One of our experts will be happy to help!** ### Related Articles ### 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. [Voice over Internet Protocol (VoIP)](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip) ### S0 bus **What is an S0 interface?** An S0 interface (sometimes also called an S interface or S0 bus) allows traditional telephone users to connect to the [Integrated Services Digital Network (ISDN)](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/isdn) and place calls over the [Public-Switched Telephone Network (PSTN)](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/pstn). It is is similar to a [router](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/router) or modem that allows users to connect to the Internet, except that it provides connectivity into the traditional telephone network instead.  Note: Even though ISDN is digital, it does not make use of the internet. [S0 bus](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/s0-bus) ### 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. 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