Ringing the Changes – The Big BT PSTN Switch off

Ringing the Changes – The Big BT PSTN Switch off

We are at the start of a new decade and the 2020’s are going to see some massive changes to the UK’s telecommunications network with the Big BT PSTN Switch off. John Dowbiggin, MD of Acuity Unified Communications explains more.

The UK’s telecoms networks will undergo substantial change in the next five years, with BT planning to shut off its traditional phone lines (the Big PSTN Switch off) in favour of internet-based systems.

If you haven’t heard, don’t worry, you’re not alone! Many businesses in the UK are still unaware this is happening.


Historically, most landline telephone services have been delivered over the Public Switched Telephone Network (PSTN). The PSTN has been in place for many decades and generally consists of copper telephone lines, fibre optic cables, microwave transmission links, satellites, undersea telephone cables and mobile networks. The PSTN is reaching the end of its life and becoming increasingly difficult and costly to maintain.

In the 80’s the Integrated Services Digital Network (ISDN) was introduced. It was designed for the digital transmission of data and voice over ordinary copper wires and relies on the PSTN to work. Although much newer, ISDN is nowhere near as advanced as some of the options that are on the market today.

Over the last decade, however, telecoms companies have built modern Internet Protocol (IP) based networks which can support both broadband and landline telephone services. While some providers have maintained two separate networks – the PSTN for call services and a separate IP network for broadband – others have replaced the PSTN and carried phone calls over the Internet.

To date, these changes have been largely invisible to customers, as providers have not upgraded all parts of their networks or have chosen to emulate how traditional call services work in customers’ homes and businesses.

The Big PSTN Switch Off

BT has announced that it will shut off its PSTN and ISDN phone lines and swap all its business customers to VoIP (Voice over Internet Protocol) and SIP (Session Initiation Protocol) solutions by 2025 (BT PSTN Switch Off). As a result, over 16 million telephone lines will be transferred to IP-based networks which support broadband-based call services. Similarly, Virgin Media intends to retire its PSTN over the next few years and currently anticipates completing its switch to IP in line with BT’s timescales.

How will the Big PSTN Switch Off affect your business?

As of September 2023* you will no longer be able to order or purchase a traditional PSTN or ISDN phone system from BT.

If you are a current BT customer and your contract is up for renewal you will need to swap your current system for a VoIP system or look elsewhere for an alternative solution.

If you are already using a VoIP system you can sit back and relax, knowing you already have a flexible, scalable cost effective solution that delivers excellent, reliable voice quality.

Preparing for the changes

Despite the fact these changes are five years away, it makes business sense to start making plans for transitioning your phone system over to an IP-based solution now. And, whilst your current communications provider is likely to make provision for moving you over by the 2025 cut-off, this is the perfect opportunity for you to review your communications needs and identify the providers that can offer you the solution you want, with the service levels you require.

Change for the better

Although it sounds like this is going to be yet another issue you have to deal with, these changes will be of great benefit to UK businesses. A business-grade hosted telephone service using VoIP will revolutionise your business communications. It offers a number of advantages for all businesses, including:-

  • Significant savings in terms of reduced telecommunications infrastructure cost, monthly recurring fees and call charges
  • Excellent, reliable voice quality.
  • Increased flexibility and scalability.
  • Powerful functionality to increase business efficiency and enhance customer service.
  • Enterprise-class technology to connect satellite offices and homeworkers but with significant cost savings when compared to similar solutions using traditional phone systems.
  • Hosted in data centres significantly reducing loss of service due to power outages

So, as we move in to the next decade it’s time to say goodbye to technology that has been around since the 19th century and boldly move to the technology of the of the 21st century.

It’s definitely a change for the better.

Acuity Unified Communications

Optimise your business communications, contact the Acuity sales team now and enquire how you can start enjoying the remarkable voice quality of Acuity’s feature-rich, business-grade Hosted Telephony solutions. With Acuity you can take advantage of significant cost savings and additional benefits, through improved efficiencies and enhanced customer service, to achieve a positive impact on your bottom line business profitability. You wont be alone, Acuity supplies Hosted Telephony services to a large number of well known organisations in the UK.

A selection of our customers include:

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