Keeping You Well Connected
Call +44(0)1935 324432
The UK PSTN Switch-Off
loss of support at the end of 2026 in ...
DAYS
HOURS
MINUTES
SECONDS
... are you ready?
.. BUT services will start to be withdrawn before this date.
Find out in this free guide what you will lose ...
Analogue lines and ISDN lines connected to your business will be switched off. .... Plan ahead before the cut-off.
Fax machines are still in use but as they use analogue lines they will stop working. These can be made to work over digital lines although it needs planning for.
This affects many services such as lift phones. Also telephony, CCTV, door entry, Telecare, alarm lines, point of sale, through to telemetry for remote monitoring systems.
Understanding the UK PSTN Switch-Off!
What Is the PSTN Switch-Off?
The UK Public Switched Telephone Network (PSTN) is being permanently retired as part of the nationwide transition to digital communications. Traditional analogue phone lines and ISDN services are reaching end-of-life and will be replaced by IP-based services such as VoIP (Voice over Internet Protocol).
Openreach has already begun withdrawing legacy services across the UK, and businesses relying on PSTN or ISDN technology must now prepare for migration before services are fully discontinued.
This change affects far more than just desk telephones. Many organisations still depend on legacy copper-based lines for critical operational systems including alarms, telemetry, lift emergency phones, payment terminals, fax systems, modem communications, CCTV connections, and remote monitoring equipment.
Fail to Plan - Plan to Fail.
Businesses that fail to prepare could experience service disruption, operational failures, compliance issues, or unexpected migration costs.he PSTN network was originally designed decades ago for analogue voice communications. Maintaining ageing copper infrastructure is becoming increasingly expensive, difficult to support, and incompatible with modern digital communication requirements.
The move to all-IP communications allows organisations to benefit from:
- Improved flexibility and scalability
- Lower maintenance costs
- Better integration with cloud services
- Enhanced disaster recovery
- Remote and hybrid working support
- Modern unified communications platforms
However, many legacy business systems were never designed to operate over IP networks and may require replacement, redesign, or specialist migration planning.
What Organisations Should Now?
1. Audit Existing Lines and Services
Many organisations do not fully understand what is connected to their PSTN or ISDN lines. A professional audit should identify:
- All analogue lines
- ISDN services
- Dependent systems
- Alarm paths
- Modem devices
- Lift lines
- Fax systems
- Remote telemetry
2. Identify Critical Services
Determine which services are business-critical and cannot tolerate failure or downtime. Priority systems often include:
- Emergency communications
- Safety systems
- Customer contact services
- Remote operational monitoring
- Payment processing
3. Assess Network Readiness
VoIP and IP-based services require stable and resilient network infrastructure.
Key considerations include:
- Internet bandwidth
- LAN performance
- Power resilience
- Backup connectivity
- QoS configurationCybersecurity
4. Develop a Migration Strategy
Every organisation has different operational requirements.
Migration planning may involve:
- SIP migration
- Cloud telephony
- Hybrid environments
- 4G/5G backup
- Replacement hardware
- Network redesign
5. Test Before Cutover
Many failures occur because systems are migrated without proper testing.
Testing should include:
- Voice quality
- Alarm signalling
- Emergency calling
- Modem compatibility
- Power fail behaviour
- Failover scenarios
6. Plan for Future Resilience
The PSTN switch-off should be treated as an opportunity to modernise infrastructure and improve resilience. Modern solutions can provide:
- Cloud integration
- Remote access
- Geographic resilience
- Improved monitoring
- Better scalability
- Reduced maintenance costs
What Services Are Affected by the PSTN Switch-Off?
Many organisations underestimate the number of systems connected to traditional phone lines. The PSTN switch-off affects much more than voice calls.
Business Telephone Systems
Legacy PBX systems using:
- ISDN30e
- ISDN2
- Analogue lines
will all need replacement or migration to SIP and VoIP-based solutions.
Alarm Systems
Many:
- Intruder alarms
- Fire alarms
- Remote monitoring systems
all still use analogue dial-up signalling or GSM backup paths that depend on PSTN based infrastucture.
Lift Emergency Phones
Emergency lift communication systems often rely on:
- Analogue lines
- GSM auto-diallers
- Legacy modem signalling
Fax Machines
Traditional fax services may become unreliable or unsupported over IP networks without appropriate configuration or replacement solutions.
Payment Terminals
Older PDQ and payment systems using dial-up connectivity must migrate to: IP-based services, Ethernet or to 4G/5G connectivity.
Telemetry and Remote Monitoring-
Many industries still use PSTN-based communications for:
- SCADA systems
- Remote telemetry
- Environmental monitoring
- Utility monitoring
- Industrial control systems
The applications often require careful redesign and testing when moving to IP-capable solutions.
CCTV and Security Systems
Some older CCTV and remote access systems use:
- Analogue dial-up
- PSTN triggered alarms
- ISDN video links for conferencing
These systems may require upgrading to fully IP-capable solutions.
Modem and Data Communications
Legacy modem applications using:
- V.21
- V.22
- V.34
- V.90
- V.110
- Circuit-switched data (CSD)
may not function reliably across VoIP infrastructure without specialist engineering support.
Industry-Specific PSTN Migration Challenges
Healthcare
Healthcare providers often rely on legacy telephony for:
- Emergency alarms
- Nurse call systems
- Lift communications
- Remote telemetry
Migration planning must consider operational continuity and patient safety.
Manufacturing and Industrial Sites
Industrial environments frequently use PSTN based systems may require specialist engineering assessment to ensure compatibility with IP networks.
Transport and Highways Infrastructure
Critical roadside and transport communications may still use PSTN network such as Emergency Roadside Telephones, GSM fallback and telemetry remote diagnostics - these environments require highly resilient communication design
About Cochrane Consulting
Cochrane Consulting provides specialist telecoms and migration expertise to organisations preparing for the UK PSTN and ISDN switch-off. With decades of experience in telecommunications engineering, network migration, GSM, ISDN, and legacy infrastructure, we help organisations identify operational risks, assess dependent systems, and plan resilient migration strategies.
If your organisation needs support assessing PSTN risks or planning migration strategy, contact Cochrane Consulting for independent technical guidance: 01935 324432.
Our Experience ...
Our experience includes work across:
- Telecom network engineering
- ISDN standards
- GSM based mobile systems
- Critical communications
- Infrastructure migration
- Legacy network technologies
We understand that many organisations still depend on systems that were never designed for modern IP environments and that successful migration requires far more than simply replacing phone lines.
Your Questions Answered
When will the PSTN switch-off happen?
The UK PSTN network is scheduled to be fully retired by 2027, with many services already being withdrawn across the country.
What happens to ISDN30 and ISDN2
ISDN services sit within the PSTN even though ISDN30e maybe connected to an organisation's PBX over fibre optic cable. The local telephony exchanges will be retired as art of the PSTN cut-off so will also stop working. These lines will need to be replaced by SIP and IP-based communications solutions assuming the the end systems are compatible.
Will analogue phones stop working?
Yes. Traditional analogue services connected directly to the PSTN will no longer operate once the network is retired unless replaced or adapted for IP services.
Will alarms and lift phones still work?
Not necessarily. Many legacy alarm and emergency communication systems are incompatible with VoIP environments and require testing or replacement.
Can I continue using fax machines?
Some fax systems may operate over IP with specialist configuration, but many organisations are choosing to migrate to digital alternatives. So its best to plan that fax will stop working unless something is done before the PSTN cutoff.
What replaces PSTN and ISDN?
Most organisations are migrating to:
- SIP trunks, Cloud telephony, VoIP platforms, 4G/ 5G where suitable.