What is the PSTN Switch Off?

The Public Switched Telephone Network or PSTN is the communication network that we have been using in the UK since 1876, and in 2025, BT Openreach will be disabling it for good.

The PSTN is a traditional circuit-switched telephone network that uses underground copper wire to connect the UK and has been connecting businesses and household for over 150 years.

BT Openreach’s ‘Big Switch Off’ campaign is taking a staggered approach of disconnecting this network, to give businesses time to make alternative arrangements.

In this blog post, you’ll learn about the PSTN, the key dates for the Big Switch Off and what alternatives are available.

Why is the PSTN being Switched Off?

It may come as a surprise that much of the infrastructure supporting communication in the UK is still transported through copper wire telephone networks that have been in place since 1876.

But in recent years, alternative technologies have emerged such as Fibre, VoIP and even Satellite based broadband that have overtaken the PSTN in capability and the Big Switch Off is paving the way for a fully digital network that can meet the demands of our new digital era.

Once the switch off has happened, communications will be delivered through a fully digital Internet Protocol (IP) that is capable of meeting current demands.

Who will be impacted?

In short, everybody.

PSTN has been the backbone of communication in the UK since it was launched in the 19th century, so both households and businesses need to prepare. This isn’t just about telephones and conversation either, things like alarms, EPOS machines, door entry systems, CCTV, and faxes have relied on the network as well.

When is the Big Switch Off Happening?

BT Openreach announced their plans in 2017 and has already started the process of turning off parts of the network.

In 2020, they Stopped sales of the network in Salisbury and added another 169 locations to the no sales zone in 2021. This year, customers using the PSTN network in Salisbury and Mildenhall have entered the end-of-life process and will have a reduced service leading to complete cease of services in the near future.

From September 2023, customers across the whole of the UK will no longer be able to purchase new Integrated Services Digital Network (ISDN) lines or add new features.

Finally, in 2025, BT Openreach will complete the end-of-life process for the entire UK. Disabling the network for everyone.

“From September 2023, customers across the whole of the UK will no longer be able to purchase new Integrated Services Digital Network (ISDN) lines or add new features”

What are the alternatives?

One of the best solutions for replacing the PSTN network is to switch to Voice Over Internet Protocol (VoIP).

VoIP works by converting your voice into a digital signal which is then transported through an internet connection and is then converted back to a regular telephone signal before it reaches the destination.

VoIP is a straightforward alternative to traditional phone systems that deliver services through Over the Top (OTT) applications, removing the need for some hardware. VoIP also gives businesses greater flexibility, allowing you to use VoIP on a range of devices, including desk phones, mobiles, tablets and computers; you can also simply access updates and new features unlike some traditional systems.

How FourNet can help?

FourNet are leaders in the delivering Communications and Collaboration platforms that will unify tools your employees need to connect, share, work together and communicate with customers.

Working with our industry leading technology partners, we are able to design and implement the right technology and communication solution for your business.

Find out more about the Big Switch Off and get in touch today to talk to an expert.