The 2027 PSTN Switch-Off: Is Your Business Ready?
The UK’s traditional phone network is being switched off.
By 31 January 2027, the old analogue Public Switched Telephone Network, better known as the PSTN, is due to be retired. This means businesses still using traditional landlines, ISDN services, or older telecoms products will need to move to modern digital alternatives.
For many organisations, this sounds like a simple phone system change. But the PSTN switch-off could affect much more than your desk phones.
It may impact your broadband, alarm systems, lift emergency lines, payment terminals, door entry systems, fax machines, CCTV monitoring and any other service that still relies on an old copper phone line.
That is why now is the time to check what your business uses, where the risks are, and what needs to be upgraded before the deadline arrives.
What Is the PSTN Switch-Off?
The PSTN switch-off is the planned retirement of the UK’s old analogue phone network.
For decades, the PSTN has carried traditional landline calls over copper-based infrastructure. It has also supported services such as ISDN, legacy broadband and other systems that use analogue phone lines.
However, the network is ageing. It is becoming more expensive to maintain, less suited to modern business needs and less reliable than newer digital alternatives.
Instead of using old analogue lines, calls and connected services will move to IP-based technology, which means they run over an internet connection.
In simple terms, businesses will need to move away from traditional landlines and onto digital services such as:
- VoIP phone systems
- Hosted telephony
- SIP trunking
- Microsoft Teams Phone
- Fibre broadband
- Digital voice services
- Cloud-based communication platforms
This change is already underway, and the final deadline is getting closer.
When Is the PSTN Switch-Off Happening?
The PSTN network is due to be switched off by 31 January 2027.
A major step has already happened. Since September 2023, new analogue phone lines have no longer been sold to new customers in the UK. This is often referred to as the PSTN stop sell or WLR stop sell.
That means businesses cannot rely on simply ordering another traditional line when something changes. If you move premises, upgrade services, change provider or need new lines, you will likely be moved towards a digital alternative.
The deadline may still feel a little way off, but migrations take planning. Businesses that leave it too late could face rushed installations, supplier delays, unexpected costs or disruption to important services.
Why the PSTN Switch-Off Matters for UK Businesses
The PSTN switch-off is not just a telecoms issue. It is a business continuity issue.
If your organisation still has systems connected to analogue phone lines, those systems may stop working properly once the old network is retired.
This could affect how customers contact you, how your team communicates, how payments are processed, how alarms are monitored and how critical safety systems operate.
For many businesses, the biggest risk is not the main phone system. It is the hidden services that nobody has checked for years.
You may already know what phone system you use. But do you know whether your fire alarm, lift line, payment terminal or door entry system still depends on a copper line?
That is where many businesses could be caught out.
What Services Could Be Affected?
Any service that uses a traditional analogue phone line could be affected by the PSTN switch-off.
Common examples include:
Business Phone Systems
If your business still uses traditional landlines, ISDN2, ISDN30 or an older PBX system, it will need to be reviewed.
You may need to move to a hosted VoIP system, SIP trunking or a cloud-based platform such as Microsoft Teams Phone.
Broadband Connections
Some older broadband services rely on copper phone line infrastructure. As the UK moves towards fibre-based connectivity, businesses may need to upgrade their broadband connection as part of their wider telecoms migration.
Alarm Systems
Intruder alarms, fire alarms and monitored alarm systems may use analogue phone lines to communicate with alarm receiving centres.
If these are not upgraded, they may stop sending alerts correctly.
Lift Emergency Lines
Many lifts have emergency communication lines that connect users to a helpdesk or monitoring centre.
These lines must be checked carefully before the PSTN switch-off, especially where safety and compliance are involved.
Payment Terminals
Some older card machines and EPOS systems still use analogue connectivity.
If your payment system depends on a traditional phone line, it may need replacing or upgrading to work over broadband, mobile data or another digital connection.
Door Entry and Access Control
Door entry systems, gates, barriers and intercoms may also depend on legacy phone lines.
These should be tested and upgraded before the deadline to avoid access issues.
Fax Machines and Monitoring Systems
Although fax usage has declined, some sectors still use it. CCTV systems and remote monitoring services may also rely on older connectivity methods.
If these systems are still important to your business, they should be included in your audit.
What Happens If Your Business Does Nothing?
Doing nothing is risky.
Once the PSTN network is retired, services that rely on it may no longer work as expected. That could create problems such as:
- Lost phone service
- Failed alarm signalling
- Payment issues
- Lift communication faults
- Customer service disruption
- Emergency communication problems
- Higher last-minute migration costs
- Supplier delays
- Business downtime
The closer the deadline gets, the busier telecoms providers, engineers and equipment suppliers are likely to become.
Businesses that act early will have more time to plan properly, test systems, train staff and choose the right solution. Businesses that leave it too late may have fewer options and a more stressful migration.
The PSTN Switch-Off Is Also an Opportunity
While the switch-off creates urgency, it also gives businesses a good reason to modernise their communications.
Moving to a digital phone system can offer several benefits.
More Flexibility
Cloud-based phone systems allow teams to make and receive calls from the office, home or on the move.
This is ideal for hybrid working, multi-site businesses and mobile teams.
Easier Scalability
Adding or removing users is usually much easier with VoIP and hosted telephony than with traditional phone systems.
This makes it easier to scale your communications as your business grows.
Smarter Call Features
Modern phone systems can include features such as call routing, voicemail to email, call recording, analytics, auto attendants and integration with CRM systems.
This can improve customer experience and help your team work more efficiently.
Microsoft Teams Integration
For businesses already using Microsoft 365, Microsoft Teams Phone can bring calling into the same platform your team already uses for meetings, chat and collaboration.
This can reduce complexity and make communication easier to manage.
Better Business Continuity
With the right setup, calls can be redirected quickly if your office loses connectivity or your team needs to work remotely.
This can help keep your business running during outages, emergencies or office closures.
What Should Businesses Do Now?
The best first step is to complete a full audit of your telecoms and connectivity.
Do not just check your phones. Check every system that may use a phone line.
Start by making a list of:
- Main office phone lines
- ISDN lines
- Broadband circuits
- Alarm lines
- Lift lines
- Payment terminals
- Door entry systems
- Fax lines
- CCTV systems
- Remote monitoring services
- Backup lines
- Lines at secondary sites or old premises
Once you have a list, identify what each line supports.
Some may be easy to identify. Others may need help from your telecoms provider, IT partner, alarm company or facilities team.
The key question is simple: what would stop working if this line disappeared?
You should also speak to third-party suppliers, especially for alarms, lifts, access control, payment terminals and monitoring systems. Do not assume everything will work automatically over a digital connection.
Choosing the Right Digital Phone Solution
There is no one-size-fits-all answer.
Your options may include:
- Hosted VoIP
- SIP trunks for an existing compatible phone system
- Microsoft Teams Phone
- Cloud contact centre tools
- Mobile-first solutions
- A mix of services across multiple sites
The right choice depends on how your team works, how many users you have, what systems you already use and what you need from your communications.
Your internet connection also matters. Digital phone systems rely on connectivity, so your broadband needs to be strong enough to support voice traffic and wider business use.
For some businesses, this may mean upgrading to fibre broadband, adding backup connectivity or reviewing the wider network setup.
Why You Should Not Leave It Until 2027
The deadline is January 2027, but waiting until then is not a good plan.
Migrations can take time. Number porting, connectivity upgrades, supplier coordination and system testing can all create delays.
Many businesses also have more legacy services than they realise. Finding and replacing them can take longer than expected.
The closer the deadline gets, the more demand there will be for telecoms providers, engineers and replacement equipment.
Early planning gives you more control. You can compare options, manage costs, reduce disruption and avoid rushed decisions.
PSTN Switch-Off Checklist for Businesses
Use this checklist to start preparing:
- Audit all phone lines and telecoms services
- Identify anything still using analogue or ISDN lines
- Check alarms, lifts, payment terminals and door entry systems
- Speak to third-party suppliers about digital compatibility
- Review broadband and connectivity performance
- Consider backup connectivity or mobile failover
- Choose a suitable VoIP, SIP or Teams Phone solution
- Plan number porting and migration dates
- Test all critical services before old lines are removed
- Train staff on the new phone system
How an IT and Telecoms Provider Can Help
The PSTN switch-off affects telecoms, IT, connectivity, security and business continuity.
That is why many businesses benefit from working with a provider that can look at the full picture, not just the phone system.
A good IT and telecoms provider can help you audit your existing services, identify hidden PSTN dependencies, recommend the right digital phone solution, upgrade your connectivity, manage the migration and support your team after the switch.
The goal is not just to replace old lines. It is to create a more reliable, flexible and future-ready communications setup.
Final Thoughts
The PSTN switch-off is one of the biggest changes to UK business telecoms in decades.
For some businesses, the move will be simple. For others, it could uncover older systems, hidden lines and critical services that all need attention.
The important thing is to start now.
By auditing your setup early, reviewing your connectivity and planning your migration properly, you can avoid disruption and use the switch-off as an opportunity to improve the way your business communicates.
If your business still uses traditional phone lines, ISDN, older broadband services or systems connected to analogue lines, now is the right time to get expert advice.
Need Help Preparing for the PSTN Switch-Off?
If you are unsure whether your business is ready for the PSTN switch-off, we can help.
Our team can review your current setup, identify any risks and recommend the right solution for your business, whether that is VoIP, hosted telephony, Teams Phone, improved connectivity or a complete communications upgrade.
Get in touch today to make sure your business is ready before the 2027 PSTN switch-off.