Traditional analogue voice lines
Legacy phone lines used for inbound and outbound voice need an appropriate replacement, often using IP-based voice or a provider-managed digital service.
UK PSTN SWITCH-OFF
Prepare Your Business for the 2027 PSTN Switch Off
The UK is moving away from the old public switched telephone network. Openreach has set 31 January 2027 as the date by which its legacy PSTN platform is due to be withdrawn. Businesses should use the remaining time to identify voice lines and other services that still depend on the old network, then migrate them in a controlled way.
QUICK ANSWER
What you need to know
The UK PSTN switch-off means businesses using legacy analogue voice services need to move to modern IP-based alternatives. The work is not only about desk phones: alarms, lift lines, payment terminals, fax services, door entry and other equipment may also depend on old analogue lines and should be audited before migration.
CHOOSING THE RIGHT OPTION
What the PSTN switch-off means for UK businesses
The retirement of the legacy network changes the access technology behind traditional voice services. Businesses should identify which services are genuinely dependent on analogue lines rather than assuming the change only affects desk telephones.
Business phone numbers
Important customer-facing numbers should be documented and their migration or porting path confirmed before the old service is ceased.
Analogue equipment and special services
Check alarms, lifts, door entry, payment terminals, fax, telemetry and other devices that may rely on analogue signalling. Speak to the equipment provider about supported replacement connectivity.
HOW IT WORKS
Build a PSTN migration plan before the deadline
A controlled migration reduces the risk of discovering an overlooked line after the legacy service has been withdrawn.
Inventory every telephone number and line
Create a list of public numbers, hidden lines, alarm lines and other circuits, including what each one is used for and who owns the replacement decision.
Decide which numbers must be retained
Customer-facing numbers may need to be ported or migrated. Confirm eligibility and lead times early rather than cancelling the old service first.
Choose the replacement voice platform
Select hosted VoIP, SIP to a compatible PBX, call divert or another suitable service based on user count, call flows, resilience and support requirements.
BUSINESS BENEFITS
Test resilience, emergency calling and business continuity
IP voice depends on power, local networks and connectivity in ways that old analogue services did not. The replacement design should reflect the impact of an outage.
Plan for power and internet outages
Consider UPS protection, resilient connectivity and alternative call routes where loss of voice service would materially affect the business.
Review emergency-calling location information
Confirm how emergency-calling address and location information is handled by the selected voice provider, especially for remote and multi-site users.
Run a controlled cutover
Test inbound numbers, outbound caller ID, key call flows and any dependent equipment before the legacy service is finally ceased.
Do not leave PSTN migration until the final weeks
Start with an inventory of numbers and analogue services, then use the UKDDI replacement checker to build a practical starting plan for each line.
RELATED UKDDI SERVICES
Continue planning your business phone service
OFFICIAL REFERENCES
Check the underlying UK guidance
Openreach: final PSTN migration deadline
Openreach business warning published 31 July 2026 confirming the 31 January 2027 switch-off target.
Ofcom: moving landlines to digital technology
Ofcom consumer and industry guidance on the move from analogue to digital landline services.
COMMON QUESTIONS
Frequently asked questions
When is the UK PSTN switch-off?
Openreach’s current target for withdrawing its legacy PSTN platform is 31 January 2027. Businesses should confirm timelines for their own provider and services rather than assuming every migration happens automatically on that day.
Will my business lose its telephone number?
Not simply because the technology changes, but important numbers should be documented and their migration or porting path confirmed before an old service is cancelled.
Does the PSTN switch-off only affect desk phones?
No. Businesses should also check alarms, lifts, door entry, payment terminals, fax, telemetry and other equipment that may use analogue lines or signalling.
What should replace a traditional business landline?
The right replacement depends on the requirement. Options can include hosted VoIP, SIP to a compatible PBX, call divert or a provider-managed digital voice service. Resilience and emergency-calling needs should be considered as part of the design.
NEXT STEP
Use the replacement toolkit
Do not leave PSTN migration until the final weeks
Start with an inventory of numbers and analogue services, then use the UKDDI replacement checker to build a practical starting plan for each line.