Are you ready for The Big Switch Off?
Time until 31.01.2027
Counting down to The Big Switch Off
The UK’s traditional telephone network is approaching the end of its working life. On 31 January 2027, Openreach plans to retire the Public Switched Telephone Network, usually shortened to PSTN. Every service that still depends on that network needs to be moved to a suitable digital alternative.
For many organisations, the obvious task is replacing an old phone system. The less obvious risk is the equipment that uses a telephone line quietly in the background. Alarm panels, lift phones, payment terminals, door entry systems and monitoring equipment can all be affected.
The deadline is now close enough that businesses should be auditing, planning and testing rather than waiting for a provider to make contact.
What is the Big Switch Off?
The PSTN is the technology traditionally used to provide analogue telephone calls. It is ageing, increasingly difficult to maintain and no longer suited to the way modern communications are delivered. Openreach is withdrawing the wholesale products that depend on it and communication providers are moving customers to internet-based services.
Voice calls will normally use Voice over Internet Protocol, or VoIP. Depending on the service, a telephone may plug into a broadband router, an analogue telephone adapter or a modern cloud phone system. Businesses can keep familiar telephone numbers when migrations and number ports are planned correctly.
The change does not mean every copper cable disappears on the same day. Broadband can still be delivered over copper in areas without full fibre, using products such as SoGEA. The important point is that the old analogue telephone service carried over the PSTN is being retired.
Which business services could be affected?
Start with anything connected to a telephone socket, but do not stop there. Some lines terminate inside a cabinet, plant room or alarm panel and may never appear on a desk.
- Telephone systems: analogue handsets, ISDN2, ISDN30, fax machines and legacy PBXs.
- Safety systems: lift emergency phones, fire alarms, lone-worker services and care alarms.
- Security systems: intruder alarms, CCTV diallers, access control and door entry systems.
- Operational equipment: payment terminals, franking machines, telemetry, gates and intercoms.
- Remote sites: lines in warehouses, plant rooms, cabins and buildings with no everyday users.
A dial tone is not proof that a device will work after migration. Ask the equipment maintainer whether the model has been tested with the proposed replacement service, and arrange a controlled end-to-end test.
Why power resilience matters
A traditional corded telephone could often continue working during a local power cut because the exchange powered the line. A digital phone service normally depends on powered equipment at your premises, including a router, network switch, phone system or optical network terminal.
If the phone service is business-critical, the migration plan should include a correctly sized uninterruptible power supply, monitored battery health and a tested fallback route. A mobile phone is useful only where the chosen network has reliable indoor coverage and enough capacity during an incident.
Organisations with lift phones, alarms, telecare or other safety-related services should involve the specialist equipment provider before changing the line. Do not disconnect a service first and try to solve compatibility later.
A practical switch-off checklist
- Find every line. Review bills, telephone numbers, sockets, comms rooms and remote locations.
- Record what each line does. Include the provider, equipment owner and business impact of failure.
- Confirm compatibility. Ask each equipment supplier what connection is supported after the PSTN closes.
- Choose the replacement. Plan VoIP, SIP, mobile or another managed digital service around the real requirement.
- Protect the power. Decide which routers, switches, handsets and adapters need battery backup.
- Migrate early. Allow time for number porting, installation, staff training and fault resolution.
- Test the whole service. Confirm incoming and outgoing calls, alarms, emergency routes and failover.
- Remove old lines only after sign-off. Keep evidence that every dependent service has passed testing.
What happens if you do nothing?
Openreach says service may be limited after 31 January 2027 if a line has not migrated. A temporary emergency voice-only service may be used in some circumstances, but it is not a business continuity plan and may not support existing calling features or connected equipment.
Leaving the work until the final weeks also creates practical risks. Engineers, number-porting teams and specialist equipment suppliers will all be dealing with the same deadline. An early migration gives the business time to correct mistakes while the old service is still available.
Start with the service, not the product
The right replacement depends on what the line is there to achieve. A small office may need a straightforward hosted phone system. A lift, alarm or remote site may need specialist equipment, mobile resilience or a managed service with clear monitoring and support. A multi-site organisation may need number porting, call routing and connectivity planned together.
Bletchley Networks can audit existing lines, identify dependencies, design the replacement connectivity and phone system, manage number porting and test the finished service. The objective is not simply to remove an old line. It is to make sure the service behind it still works on 31.01.2027.