The PSTN switch off is no longer a distant change. The UK’s traditional analogue phone network will be permanently switched off in January 2027. That date is confirmed by Openreach, and it affects every business still relying on legacy phone lines or ISDN services.
For many organisations, this is more than a telephony upgrade. The PSTN switch off UK programme affects phone systems, broadband connections, alarm lines, payment terminals, lift emergency lines and other services that depend on analogue infrastructure.
If your business has not reviewed its connectivity strategy recently, now is the time.
Active Digital has supported infrastructure transitions for over 32 years, helping organisations modernise voice and connectivity systems with minimal disruption. With 97% client retention through major technology shifts, we understand how to move businesses forward safely and strategically.
What is the PSTN switch off?
The Public Switched Telephone Network, or PSTN, is the analogue network that has supported UK landlines for decades. It carries voice calls over copper lines and underpins many legacy systems.
The PSTN switch off means this analogue infrastructure will be retired and replaced by digital, IP-based services.
This also includes the ISDN switch off. ISDN, or Integrated Services Digital Network, is a digital telephony service delivered over the same copper infrastructure. It too will be permanently withdrawn by January 2027.
In simple terms, traditional analogue and ISDN phone lines will no longer work after January 2027.
When is the PSTN switch off happening?
The confirmed PSTN switch off date is January 2027.
New PSTN and ISDN services are already being withdrawn in many areas. The final nationwide shutdown is scheduled for January 2027, at which point the legacy network will be fully decommissioned.
Businesses should not wait until the final deadline. Lead times for new installations, especially where network redesign is required, can be significant.
What lines are affected by the PSTN switch off?
The PSTN switch off affects:
- Analogue telephone lines
- ISDN2 and ISDN30 services
- Traditional business phone systems connected via copper
- Broadband services delivered over analogue lines
- Alarm systems using PSTN
- Lift emergency lines
- Fax machines
- EPOS terminals relying on analogue dial-up
- Door entry and access systems connected to landlines
If your organisation uses any service that depends on a copper-based phone line, it will need to be reviewed.
Many businesses assume this change only affects voice calls. In reality, it impacts a wider range of connected systems.
For a broader overview of the landline withdrawal, read our guide to the landline switch off.
What replaces PSTN?
The replacement for PSTN is digital connectivity delivered over IP networks.
The most common alternatives include:
VoIP
VoIP, or Voice over Internet Protocol, routes calls over your internet connection rather than a copper phone line. Calls are delivered through hosted telephony platforms, desk phones, softphones or mobile apps.
SIP trunking
SIP trunking connects your existing on-premise PBX to the internet for digital call delivery. This can be suitable for organisations with established phone systems that require integration rather than full replacement.
Hosted telephony
Cloud-based hosted phone systems remove the need for traditional PBX hardware. They offer flexibility, remote working capability and simplified scaling.
Fibre and Ethernet broadband
Because voice will run over IP, stable broadband becomes critical. Many businesses upgrading from PSTN also review their data connectivity, moving to fibre or leased lines for greater reliability and performance.
Will my broadband be affected by the PSTN switch off?
It depends on how your broadband is delivered.
If your broadband is currently provided over an analogue copper line, it will be affected. In many cases, this will require migration to fibre-based broadband or Ethernet services.
Businesses using FTTC or FTTP services may already be operating over digital infrastructure, but voice services connected to copper lines will still need upgrading.
The safest approach is to review both voice and data together. Migrating voice without assessing bandwidth and resilience can create performance issues.
What is ISDN and is it being switched off too?
ISDN is a digital telephone service delivered over copper lines. It has historically been used by businesses requiring multiple simultaneous calls or higher voice quality than analogue lines.
ISDN is being switched off alongside PSTN in January 2027.
If your organisation still uses ISDN2 or ISDN30 circuits, you will need to migrate to SIP trunking or a hosted VoIP platform.
Does the PSTN switch off affect alarm lines?
Yes. Many alarm systems, fire panels and monitoring devices use PSTN lines to signal alerts. After January 2027, these lines will no longer function.
Alarm providers must transition to IP-based or GSM-enabled signalling methods.
This area is particularly important because it intersects with compliance and insurance requirements. Businesses should review:
- Intruder alarms
- Fire alarms
- Lift emergency phones
- Access control systems
- Monitoring services
The transition should be planned carefully to avoid downtime or regulatory risk.
What is the difference between PSTN and VoIP?
PSTN uses copper lines to transmit analogue voice signals. It relies on legacy infrastructure that is being retired.
VoIP transmits voice digitally over internet connections. It does not rely on copper lines and allows calls to be delivered across broadband, fibre or Ethernet connections.
VoIP supports:
- Remote working
- Flexible call routing
- CRM integration
- Scalable user numbers
- Cost efficiency for multi-site operations
For most businesses, the PSTN switch off becomes an opportunity to modernise rather than simply replace like for like.
What you need to do before January 2027
Below is a structured summary of practical steps businesses should take before the PSTN switch off date.
1. Audit all phone lines and connected services
Identify every PSTN and ISDN line in use. Include alarm systems, lifts, fax lines and payment terminals.
2. Review broadband delivery method
Confirm whether your broadband depends on analogue infrastructure.
3. Assess business-critical systems
Identify which services require guaranteed uptime and consider whether resilience or backup connectivity is needed.
4. Choose the right digital replacement
Decide between VoIP, SIP trunking or hosted telephony depending on your operational model.
5. Upgrade connectivity where required
Ensure broadband or Ethernet capacity supports voice and data demand.
6. Plan the migration timeline
Avoid last-minute changeovers. Schedule installation, testing and staff training well in advance.
7. Communicate internally
Ensure teams understand what is changing and how calls will be handled.
How do I prepare my business for the PSTN switch off?
Preparation is less about panic and more about planning.
Start by asking:
- How many lines do we have?
- What systems rely on them?
- Are we using ISDN?
- Is our broadband copper-based?
- Do we require SLA-backed connectivity?
- Are we planning site moves or infrastructure changes?
For multi-site businesses, migration can be phased. For regulated environments, compliance and resilience should lead the design.
A well-planned transition can deliver improved call quality, lower costs and greater flexibility.
Why acting early matters
Although January 2027 is confirmed, demand for upgrades is increasing as awareness grows.
Waiting until late 2026 may create:
- Installation delays
- Limited engineering availability
- Reduced choice of solutions
- Increased operational risk
Planning now allows for controlled implementation rather than reactive replacement.
The commercial opportunity behind the change
The PSTN switch off UK programme is often viewed as a forced upgrade. In practice, it is an opportunity.
Modern IP-based voice systems allow:
- Integration with Microsoft Teams and CRM platforms
- Flexible hybrid working
- Centralised call reporting
- Scalable user licensing
- Reduced dependency on physical systems
For businesses reviewing digital transformation more broadly, voice migration can align with wider infrastructure improvements.
How Active Digital supports PSTN migrations
We approach the PSTN switch off as an infrastructure transition rather than a product sale.
Our process includes:
- Full estate audit
- Connectivity review
- Risk assessment
- Replacement design
- Installation coordination
- Testing and failover configuration
- Ongoing support
Because we manage both voice and connectivity, we ensure your broadband and telephony work together effectively.
With 32 years of experience supporting infrastructure change, we have guided clients through ISDN transitions, fibre rollouts and network redesigns. The PSTN switch off is another major milestone, and it should be handled carefully.
PSTN switch-off FAQs
- When is the PSTN switch off happening?
The confirmed PSTN switch off date is January 2027. After this date, analogue and ISDN lines will no longer operate in the UK.
- What lines are affected by the PSTN switch off?
Analogue PSTN lines, ISDN services and any systems relying on copper phone infrastructure are affected, including alarms and lift lines.
- What replaces PSTN?
Digital IP-based services such as VoIP, SIP trunking and hosted telephony replace PSTN.
- Will my broadband be affected?
If your broadband runs over an analogue copper line, it will require migration to fibre or Ethernet-based services.
- Does the PSTN switch off affect alarm lines?
Yes. Alarm systems using PSTN must transition to IP or GSM-based signalling before January 2027.
Speak to us about the PSTN switch-off
If you are unsure how the PSTN switch off affects your organisation, now is the time to review your setup.
We can assess your current lines, identify affected services and design a clear migration plan.
Visit our VoIP and leased lines pages to explore replacement options, or contact us to discuss your business requirements directly.
