Why Is the PSTN Switch-Off a Priority for Businesses?

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The UK has been reliant on the Public Switched Telephone Network (PSTN) since the 19th Century, but the Big Switch Off in December 2025 will mark the end of an era, seeing the country move fully into the digital age.

As a business, you’ll need to ensure that you have the right infrastructure in place to support newer technologies like voice over internet protocol (VoIP).

You might commonly understand the PSTN network as the network that connects to landline phones. PSTN has been in use since the 1800’s and has relied on underground copper wires to provide businesses and households around the UK with a phone connection.

With the switch off happening, many businesses are making the move to VoIP systems which rely on an internet connection to make and receive calls. Take a look at our guide to the best business VoIP providers in the UK to see what your options are.

What is the Big Switch Off?

The PSTN network has been in use since the 1800's, but as you can imagine, today's communication demands have increased and speed and reliability have become the main priorities. This old network can no longer support the demand of modern day communication and it is currently being replaced with a fibre network.

Any phone lines and services that rely on PSTN can no longer be used once the PSTN network is switched off by BT OpenReach in December 2025. However, the process has already started and the network has already been switched off in some areas, so the faster you change your phone system, the better.

Businesses will no longer be able to communicate over the old network and will have to switch to a network such as VoIP which uses internet connection as opposed to the copper-based network. VoIP is also more reliable and affordable compared to the old network.

What is the process for the transition away from the PSTN?

Back in 2017, BT Openreach announced the Big Switch Off, which essentially means it will shut down the PSTN due to its outdated technology and expensive upkeep. Since then, there has been a process of reducing the sale of analogue products and services, while encouraging the switch over to a digital network before December 2025.

If you're a bit lost when it comes to switching your phone line provider, check out our guide on how to change your landline provider.

Who is impacted by the PSTN Switch off?

Businesses and households in the UK that make and receive calls over PSTN lines are impacted by the switch off. As the network is slowly turned off, both businesses and households may experience severe disruption or even a complete loss of service.

Although many have now moved over to newer, reliable technologies such as VoIP, there are a large number still using PSTN lines.

In a survey carried out by Spitfire Network Services, 72% of the UK businesses surveyed did not see the PSTN switch off as a priority. This means that when the switch off occurs these businesses may not have the right infrastructure in place to support digital tech, like VoIP.

What does the PSTN switch off mean for my business?

The switch off may mean a number of things for your business, including:

  • Switching: You'll need to check if your current provider offers an alternative, such as. Most providers will offer newer, digital technologies, like VoIP and you'll be able to make the switch with them.
  • Purchasing new hardware: Newer technologies may require different infrastructure and hardware, so be prepared to purchase this.
  • Training: Once you've switched to a new system, you may need to offer training to your employees, ensuring a seamless transition.

It is worth noting that these changes will have costs associated with them, but newer tech, like VoIP, is actually much cheaper to run than PSTN lines. One of the reasons BT opted to switch off these older lines was because the upkeep was expensive and the cost was trickling down to the end user. As VoIP uses an internet connection, it's cheaper and more reliable.

There may also be costs linked to training your team, but these should be one-off as your team will be able to share their learnings with new staff.

VoIP systems need a modem and router to work. If you don't have these, you'll need to purchase them before switching over. Although, most businesses will have these in place as they’re typically part of current internet setups. Another bonus is that VoIP calls can be made over a smartphone, laptop, desktop, or a VoIP phone. Each business is different, so the mode you use for calls and the hardware you may need to purchase will vary.

A large number of businesses are already using VoIP, with the European market currently worth around $39 billion.

How to prepare my business for the Big Switch Off?

To ensure a seamless transition for your business, here is our step-by-step guide to prepare for the PSTN switch off::

  1. Check your current infrastructure to assess what currently relies on PSTN lines. This could be phones, fax machines, and any other appliances that use a landline.
  2. If you've determined that you need to make the switch, reach out to your current provider to see if they offer VoIP. If not, you'll need to find a new provider. You can start the search by looking through our guide to the best phone systems for small businesses.
  3. Once you've spoken to your provider and decided how much of your infrastructure will need to be replaced, plan to transition to newer technologies. Write up a timeline and a budget to ensure a smooth transition. Bear in mind that newer tech will require a sufficient internet connection.
  4. You may need to purchase new phones, software, or hardware that supports VoIP and digital communication.
  5. Provide training to employees on how to use the new software and hardware.

To simplify the switch, you can use our free quote comparison tool, and you’ll be matched with the top VoIP providers. Just give us a few details about the needs of your business and we'll match you with providers suited to your needs. You'll then be contacted by the providers with obligation-free quotes. It’s that simple.

Is it hard to switch telephone systems providers?

We won't beat around the bush: switching telephone system providers can cause a fair amount of disruption. To mitigate this, you'll need to plan effectively. You can do this with your provider or consult this guide to ensure you cover your bases.

As you may need to change your equipment and infrastructure, there could be initial teething issues that will need to be dealt with. Your provider should be able to assist you with this – which is why it's important to choose a provider that offers great help and support.

If your current software won't work with a VoIP system, you may need to change this, which can also cause disruption. If you're switching to new hardware and software, co-ordinate this move to ensure a smooth transition.

If you’re switching providers and want to keep your current phone numbers, you'll need to request number porting from your previous provider to your new provider, which can take several weeks to complete.

As VoIP systems run over the internet, you'll need to ensure your current connection has enough bandwidth to be used for VoIP. If it's not, you may need to consider upgrading.

Training your team will also require extra costs and there may be disruption as your team gets used to the new system.

All of the above will cost you money and could potentially affect revenue. However, if you don't switch, your current lines will likely be affected, face random service disruptions, and eventually cease to work.

As long as you plan accordingly and work with your new provider to ensure a smooth transition, you should be able to make the switch with minimal disruption.

What if I don’t switch telephone systems providers?

The PSTN target cut off date is December 2025. By this date the network will no longer work and you won't be able to use landlines. However, as BT works towards meeting this deadline, some areas have already lost network access.

Failure to switch to a newer network can mean a few things for your business, including:

  • Service disruption – your business may face unexpected loss of service or disruption.
  • Difficulty making and receiving calls – if your business is still on the old network, you may struggle to make or receive calls to and from users who have already switched to VoIP.
  • Higher costs – one of the reasons PSTN is being cut off is because of high maintenance costs. The longer you stay with the network, the higher your costs will likely be, compared to a VoIP provider.
  • Less productivity – VoIP systems have a lot more functionality when compared to landlines. Many include spam prevention, team messaging, and third-party software integrations, like a CRM system, providing your business with a seamless and efficient system.
Verdict

The planned PSTN switch off is December 2025, but some areas have already been affected by a disruption of service or a complete loss of service. To avoid this, and to plan in advance for a potentially costly switch, we recommend reaching out to your provider to check if they support a newer phone network, like VoIP.

Switching to VoIP will provide you with a faster, reliable, and advanced system when compared to a landline, but you'll need to ensure that you have the right infrastructure and hardware to ensure your business can support a new telephone system.

Switching can be a process and may involve training and purchasing new equipment, so the quicker you change phone systems, the less likely you'll have to face your landline being abruptly cut off, which could be pretty bad for business.

We recommend taking a look at our guide to the best cloud phone systems to find a provider that’s aligned to a newer, digital network.

Written by:
Zara Chechi
Zara is a Payments Expert, specialising in writing about Point of Sale systems. With a Law Degree from City University of London, she has used her legally-honed research and analytical skills to develop expertise in the Business Services world. Featured in FinTech Magazine, she quickly became an expert in payroll, POS systems, and merchant accounts.