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
  • Integrated Services Digital Network (ISDN) telephone connections
  • Voice-over-IP (VoIP) telephone connections

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). 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 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 and 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.

Why is ISDN being decommissioned?

ISDN is being decommissioned for a number of reasons, mostly to do with future-proofing service providers’ operations. Key reasons include:

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.

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ISDN was developed in the 1980s and relies on outdated hardware and software that is costly and time-intensive to maintain and support.

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 to keep users’ data safe.

When is ISDN being decommissioned?

There are different dates set for different countries. In Germany, major telephone service providers are planning to decommission ISDN in 2018. 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 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: 

Further information

Voice over IP

What is Voice over IP (VoIP)?
Voice over IP (VoIP) is the most common method for making phone calls over the internet. This is in contrast to traditional telephony, where communication is over the…

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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) and place…

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