PSTN Switch Off: All You Need to Know - National Business Communications

All You Need to Know About the PSTN Switch Off

April 27, 2023

As the PSTN switch off draws nearer, it’s essential that homes and businesses are prepared to upgrade. In this comprehensive guide, we’ll explain what PSTN is, why it’s being switched off, who’s affected, and more, giving you all you need to know to stay ahead.

What is PSTN?

The Public Switched Telephone Network (PSTN) refers to the traditional circuit-switched telephone network that’s been in use since the late 1800s. The network functions using underground copper wires, and has provided a reliable means for individuals and businesses to communicate for decades.

What is the PSTN switch off?

The PSTN switch off refers to the gradual phasing out of the public switched telephone network, with the plan for it to be fully closed down by 2025. The goal to upgrade old analogue networks to fully digital networks comes as part of a strategy to modernise communications infrastructure, meaning every phone line will route calls over Internet Protocol (IP) rather than the current PSTN.   

Why is PSTN being switched off?

While PSTN has been the keystone of worldwide communication for decades, it’s no longer capable of meeting the demands of a hyper-connected world. Technology is developing exponentially, and the increasing dominance of the internet, smartphones, apps, the cloud, and so on requires a more modern infrastructure to process such high quantities of data. IP is a 21st-century technology to match the demands of modern communications, and represents a natural and convenient next step to PSTN.

What lines will the PSTN switch off affect?

The switch off will impact all traditional PSTN lines, including:

This switch to a full-fibre network will impact individuals and businesses, so it’s essential everyone is prepared to upgrade ahead of 2025.

When is the PSTN switch off?

BT plans to complete the PSTN switch off in December 2025. After this point, PSTN-based services will no longer function, so upgrading in advance is vital.

BT first announced its plans for the phase-out in 2015; in 2023, it will stop the sale of traditional phone lines ahead of the December 2025 shutdown.

Who will the PSTN switch off affect?

Individuals and businesses throughout the UK still rely on traditional phone lines delivered by the PSTN, so anyone who’s not upgraded to more modern broadband services will be affected.

How to prepare

To prepare for the PSTN switch off, individuals and businesses should look into the new services that will replace traditional phone lines.

What will replace PSTN?

There are a range of fibre-based technologies that will replace PSTN, including:

Advantages of the PSTN switch off

Benefits of the PSTN switch off include:

Improved call quality

IP systems can process more high-quality data, making for better call quality.

Faster data transmission speeds

More modern technology means businesses using VoIP systems will benefit from faster data transmission speeds.

A more reliable and efficient system

VoIP phones are faster and more reliable than landlines – all you’ll need is an internet connection!

Increased connectivity wherever you are

VoIP systems allow you to stay connected wherever you are. Regardless of whether you’re in the office or working remotely, communicating with your team and your clients will be easy.

Affordability and flexibility

Running calls over the internet allows for more flexibility and is more cost-effective than using typical PSTN lines, helping your business save money.

A range of new features

VoIP systems come with a range of features, including call handling, voicemail, call recording, and more. Choose features that suit your business for maximum efficiency.


Internet-based systems are easy to scale up and down, meaning you can easily add or remove lines should you need to.

What should I consider before the PSTN switch off?

Before the PSTN switch off, it’s important to consider which VoIP or fully hosted PBX system you’re going to switch to. You should also check that your internet connection is durable enough to cope with your new, upgraded network to avoid any obstacles. Learn more about internet speeds in our helpful guide, and browse our superfast business broadband deals to find one that meets your business needs.

How to choose which system to upgrade to

The system you upgrade to will depend on the needs of your business. With a range of features and benefits to each, it’s a good idea to speak to an expert who will be able to give you more information.

If you have any questions, feel free to contact us on 0330 311 1133 – a member of our team will be happy to help. You can also view which phone line is best for your business in our guide.

How do you switch to an IP system?

Once you’ve decided to switch to an IP system, it’ll help to have a think about what features you’ll need. Get in contact with providers to see what they can offer and pick one that best suits your business. Providers will be able to offer guidance on the PSTN switch off, and will help you through the process step-by-step.

At NBC, we pride ourselves on our quality products and services; our customer reviews are testament to this! Learn more about why to choose NBC, and take a look at our impressive  VoIP phone system packages today.

Frequently asked questions

What’s the difference between PSTN and ISDN?

The function of ISDN is to enable transmission of voice and data over PSTN lines. Therefore, the PSTN switch off will also render ISDN obsolete.

Learn more about the ISDN switch off in our helpful blog.

What’s the difference between PSTN and VoIP?

PSTN relies on circuit-switched copper phone lines to transmit analogue voice data. Voice over Internet Protocol (VoIP) turns audio signals into digital transmission data that can be sent through the internet. VoIP software allows users to make calls over the internet without the need for a traditional phone line, and will soon take the place of physical phone systems.

VoIP is a cheaper, quicker, and more reliable solution than PSTN.

What does the PSTN switch off mean for businesses?

The PSTN switch off will make all traditional phone lines obsolete. Any businesses that still rely on analogue or digital lines, ISDN phone systems, or even internet connections like ADSL and FTTC will need to ensure they upgrade to a full fibre connection prior to December 2025.

Will I be able to keep my number after the PSTN switch off?

In most cases, numbers will be transported from landline to VoIP after the PSTN switch off.

When do I need to upgrade to VoIP?

The PSTN switch off will be complete in December 2025, so it’s important to upgrade to a fibre-based system before this date.

Is the PSTN still circuit-switched?

The PSTN still uses circuit switching for connecting calls. In contrast, VoIP systems use digital packet switching – a more efficient method that involves sending and receiving data as and when needed.

What is Openreach?

Openreach was created in 2006 to provide equal access to the telephony network in the UK. Their telephone products allowed communication providers to offer services without having to maintain the network themselves. 

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