What is the PSTN Switch Off and what does it mean for my small business?

The planned Public Switched Telephone Network (PSTN) switch off is due to be complete by January 2027. All business and home phone services will move from analogue to faster Voice over Internet Protocol (VoIP) services. Named the ‘Big Switch Off’, the move has major implications for small businesses in the UK.

2027 might seem like a long way off, but it’ll come around sooner than you think. Experts have warned businesses they should start preparing for the changeover as soon as possible.

Get a head start now, and you can save yourself time and money. Our guide will outline what all the risks and opportunities will be for small businesses, and how you can get ready.

Upcoming PSTN Switch Off dates

• December 2025 – date the PSTN was due to be switched off
• January 31 2027 – new date that all home or phone calls will be made via a VoIP-based system (What is VoIP?)

What is the PSTN Switch Off?

PSTN stands for Public Switched Telephone Network, and it’s the traditional phone network that was first established in 1875. BT Openreach has announced that the equipment is now too old to stay in use: according to Ofcom, in 2023, there was a 60% increase in the number of service hours lost to customers due to service incidents on the PSTN.

BT Openreach has already begun to upgrade the old copper wires that currently make up the PSTN. By 2027, it aims to have swapped all these wires out for fibre-optic cables. As a result, every home and business in the UK will be moved onto a digital network from January 2027.

Remember that this will be rolled out in phases — it won’t be like flipping a switch — so make sure you’re prepared in plenty of time. You can contact BT Openreach to find out when the switch will be happening in your area.

In September 2023, telephone providers began the ‘PSTN stop sell’, meaning you can no longer buy phones that use the copper network. You will now need to buy a modern communication system hosted via VoIP.

What is the ISDN Switch Off?

The ISDN was introduced to the PSTN in 1986 by BT to transmit data that the PSTN couldn’t facilitate previously, like video calls.

However, the ISDN is now outdated and only available in older teleconferencing systems and similar legacy systems.

Like the PSTN, the ISDN will be shut down in January 2027 in favour of modern technologies like VoIP.

Why are landlines being switched to VoIP?

Overall, VoIP is more reliable than PSTN. PSTN uses old copper wiring to relay data, which is subject to damage and more likely to experience poor connectivity, whereas VoIP is run with fibre optic. The other pros for SMEs include:

• Better connectivity: faster will improve your team’s productivity and overall output, having a positive impact on profitability.
• Improved customer relationships: having a faster, more stable telephone infrastructure means better call quality, which makes for a better experience for clients and customers.
• Flexible packages: because most VoIP packages work on a per-user pricing model, SMEs can save money by prioritising the connections they require.
• Cheaper deals: VoIP is typically cheaper to run (and cheaper for customers) than the old copper network as it doesn’t rely on expensive infrastructure. Plus, VoIP prices will become more competitive over time as Openreach incentivises suppliers to move over to future-proofed products.
• Better for remote working: VoIP systems work from anywhere, so you can get them set up for home working. Kristian Torode, the director and cofounder of business telecoms provider Crystaline, explains that by using VoIP number porting, “…any device can connect to the system on one phone number to support flexible working.”

Tom Grange is the head of connectivity at Bionic, a business broadband provider. Grange explains, “The service is quicker and more adaptable than copper and ISDN lines. Calls can be made from smartphones and laptops from wherever you are, with high-quality sound.”

How will I be affected?

Telecoms providers will take care of much of the migration admin by contacting customers at least four weeks ahead of any switching over taking place in their region, and helping them switch to VoIP.

However, savvy business owners are advised to be proactive, and use this time to research the costs of a VoIP system and upgrade to a platform that’s the best fit for their business and the best value for money, whether that’s a fully kitted-out business telephone system with VoIP handsets, or just an app-based virtual landline.

The bottom line: If you use a PSTN phone system (or any other services that are connected to the ISDN) you need to look into switching to a VoIP phone system as soon as possible to make sure you get the best deal and the right software for your business.

What else will be affected by the switch off?

It’s not just your phones. Once the PSTN has been turned off, businesses will lose all service to any legacy systems they’re using that are connected to the ISDN, such as:

• Alarm systems
• ATM machines
• Franking machines
• Fax machines
• Printers
• Dial-up POS (card machines)
• Video conferencing
• Live streaming
• File downloading

If that affects you, you’ll need to find replacement equipment and services that are powered by wifi instead of the ISDN. VoIP software can carry phone calls, video conferencing, file sharing, and more, but it can’t host card machines and the other hardware listed above.

Sara Sheikh is the head of product management at Gamma, a telecommunications provider. Sheikh predicts that the PSTN Switch Off “will have far-reaching implications for every industry” including brick-and-mortar businesses.

“Retail, hospitality, and other customer-facing businesses will need to update their systems to ensure that they can still provide quality customer service,” she clarifies.

When do I need to switch?

Although the official switch off won’t happen until January 2027, switching to a modern, VoIP-based telephone provider should be done as soon as possible.

That’s because not switching soon enough brings risks to businesses.

Torode cautions that “There could be some interruptions to services as businesses scramble to upgrade,” and “There are over 25 million connections to be switched over by the deadline. Making the switch sooner rather than later will be essential.”

The risks for businesses of not switching to a VoIP system in time include:

• Choosing the wrong supplier: give yourself time to research the best business telephone providers and save money in the long-term
• Increased costs: get a deal early – supplier scaremongering could see VoIP prices getting pushed up closer to the deadline
• Missing out on fast broadband: with some locations already offering fibre-optic internet, you could already be missing out on the benefits

How do I switch to VoIP?

We outline the five steps to install VoIP in our comprehensive guide on how to prepare for the PSTN Switch Off.

Here’s a quick overview of the key points:

• Put together a detailed migration plan as soon as possible. Consider budget, required features, infrastructure needs, and employee training.
• Partner with the right provider. Research the top VoIP providers to ensure you are fully aware of each company’s pros and cons.
• Seek out recommendations and advice from fellow business owners and read reviews to make an informed decision.
• If you want to stick with your current provider, start a conversation with their customer service team now about the options available. Should you need to buy new equipment, like a new router, your provider should automatically arrange this.

It might sound like a hassle, but in the long-term, you should save money as a result of switching. IP is typically cheaper to run than the old copper network as it uses the internet, not expensive infrastructure.

> Read our guide to installing a VoIP telephone system to prepare for the Big Switch Off.

What should I look for in a VoIP phone system?

Duncan Shaw, the director at Connectus, a tech firm, recommends that SMEs don’t see the switch-off as a straightforward process of replacing what they have today. “Consider how you want to make communications work for you to maximise your ability to reach customers.”

1. Connectivity: perhaps the most important aspect of a telephone provider is the strength of their connection. Be sure to carry out thorough research into every brand’s broadband speed. That way, you can have confident in a reliable connection that will keep you closely connected with customers.

2. Flexibility: if you have a hybrid workforce, it makes sense to purchase business mobile phones rather than upgrade to a brand-new telephone system. “It’s vital to take informed decisions, remove risk, and minimise the complexity from the process,” says Shaw. “This, in turn, will help you to control costs.”

3. Number porting: this is the process of moving a telephone number from one communications provider (CP) to another. It can take weeks, depending on the system you use, so it’s a good idea to ask your provider how long the change will take to mitigate any business disruption.

Next steps

Migrating existing business technology is stressful. But it’s important that SMEs recognise the huge opportunities that the Big Switch Off presents – not just the challenges.

Making the switch to a VoIP subscription as soon as possible will give business owners access to a much cheaper and more powerful call infrastructure. IP systems give firms access to high-quality lines, which can boost productivity and help ensure a seamless customer experience.

Start by comparing quotes with our simple cost comparison webform to find the best provider for your budget. It’s entirely free and will recommend the most suitable VoIP system for you based on your unique user needs and feature requirements.