Overview
The UK’s Public Switched Telephone Network (PSTN) and Integrated Services Digital Network (ISDN) are being retired. The full switch off is scheduled for 31 January 2027, meaning traditional analogue and ISDN phone lines will no longer function.
BT originally planned to complete the closure by the end of 2025, but the deadline has been officially extended to 2027. This gives households, businesses, and service providers more time to adapt and ensures that critical systems like telecare and personal alarms continue working during the transition.
Why PSTN and ISDN Are Being Retired
PSTN has been used for decades, carrying voice calls over copper lines and supporting services such as fax, dial-up internet, and card payment machines. ISDN, introduced later, allowed multiple digital voice and data channels.
Both technologies are now being phased out because:
- Maintaining copper networks is costly and inefficient.
- PSTN and ISDN cannot easily support modern digital communications.
- VoIP and IP-based phone systems offer greater reliability, flexibility, and scalability.
Key Dates to Remember
- 5 September 2023 – BT introduced a “Stop Sell”: new PSTN and ISDN services are no longer available. Existing lines continue until the switch off.
- 31 January 2027 – final PSTN and ISDN switch off across the UK.
Services and Equipment That Will Be Affected
The retirement of PSTN and ISDN affects more than just phone lines. Any device or service relying on analogue or ISDN connections may stop working. Examples include:
- Alarm systems, including security and fire alarms
- Telecare and personal alarms for vulnerable users
- Payment terminals (PDQ / EPOS machines)
- Door entry systems and lifts with emergency phones
- Fax machines
- Older broadband services that depend on copper lines (ADSL, FTTC with analogue voice)
If you are unsure, confirm with manufacturers or suppliers whether your equipment is compatible with IP-based services.
Replacement Options for PSTN and ISDN
To maintain communication services after 2027, households and businesses must transition to digital solutions. Common replacements include:
- VoIP (Voice over Internet Protocol) – modern phone services over broadband, allowing retention of existing numbers.
- FTTP (Full Fibre Broadband) – faster, more reliable internet connectivity.
- SoGEA (Single Order Generic Ethernet Access) – broadband without the need for a traditional phone line.
- Cloud-based phone systems – enabling calls, voicemail, and collaboration tools on multiple devices.
Analogue Terminal Adaptors (ATAs) can bridge older handsets to IP networks, providing a smoother transition.
How Tawk Can Help With the PSTN Switch Off
Transitioning from legacy PSTN and ISDN services to modern, future-proof solutions can be complex. Tawk provides expert guidance and practical support for businesses and households, helping to ensure a smooth, disruption-free migration.
Our services include:
- Audit and assessment – review existing phone lines, broadband, and connected equipment.
- Migration planning – create a clear, step-by-step plan for moving to IP-based systems.
- Upgrades and implementation – deploy VoIP, fibre broadband, and cloud telephony.
- Business continuity support – ensure alarms, emergency calls, and critical systems remain operational.
For advice and support, visit www.tawk.network via the contact section or call us on 01527 868400.
Steps to Prepare for the PSTN and ISDN Switch Off
Even with the 2027 deadline, early preparation is key. Recommended actions include:
- Audit your equipment – identify devices still relying on PSTN or ISDN.
- Check compatibility – confirm which systems will work over VoIP or need replacement.
- Upgrade broadband – ensure a reliable IP connection through FTTP or SoGEA.
- Plan migration – coordinate with your provider to retain phone numbers and maintain continuity.
- Test critical systems – alarms, telecare devices, and payment terminals must be verified to work on the new infrastructure.
Conclusion
The PSTN and ISDN switch off in the UK is a significant change, but it also presents an opportunity to modernise communications. Moving to VoIP, fibre broadband, or cloud-based telephony improves reliability, flexibility, and future readiness.
Tawk can guide you through the process, helping you transition from legacy systems to modern, digital communication solutions. Visit www.tawk.network or call 01527 868400 to discuss how we can support your migration before the 2027 switch off.
