PSTN switch-off 2027 · UK business guide
The analogue phone network hangs up for good on 31 January 2027.
The PSTN switch-off is the retirement of BT’s traditional telephone network, scheduled for 31 January 2027. Often called the landline switch-off, it affects businesses still using analogue phone lines or ISDN services on that network. Here’s how to plan your move to a digital phone service.
The withdrawal
What is the PSTN switch-off?
PSTN stands for Public Switched Telephone Network. BT is retiring this ageing network, and Openreach is withdrawing the Wholesale Line Rental (WLR) services that depend on it, including analogue lines, ISDN2 and ISDN30. Your provider may use Openreach’s network even if your bill doesn’t come from BT.
The digital phone switchover moves calls onto an internet connection using Voice over Internet Protocol, or VoIP. The change doesn’t mean every copper cable is being removed or that every business needs full fibre.
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Withdrawn 31.01.2027
Analogue phone lines
Traditional phone lines supplied over Openreach’s WLR services.
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Withdrawn 31.01.2027
ISDN2 & ISDN30
Openreach’s legacy digital lines for on-site phone systems.
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Replaces them
Phone service over broadband
Known as VoIP. Calls travel over your internet connection.
Line check
Is your business affected by the landline switch-off?
sound familiar?
- Your phones plug into a phone socket in the wall, not into your internet router.
- You have ISDN lines and an on-site phone system (PBX).
- An alarm, lift line, card terminal or fax machine dials out over a phone line.
- You’re not sure whether your phone service is already digital.
If any of these sound familiar, check with your provider. A wall socket alone doesn’t tell you what service you have. Ask which lines and connected devices need attention, and when your provider plans to migrate them. Businesses already using VoIP may still have separate analogue lines for alarms or other equipment.
Not sure where to start? Talk to us about switching and we’ll help you work out your phone service options.
The switch
How to move your business phone service to VoIP.
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Check your lines, broadband and equipment
List your phone numbers, broadband services, alarms, lift phones, door entry systems, card terminals and fax machines. Ask each equipment supplier whether its devices will work after the switch. Check whether transferring your phone number would also cease the broadband on that line.
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Prepare your digital phone service
Choose a hosted phone system or SIP trunks to suit your business. Arrange any replacement broadband and equipment before the number transfer. Set up your call routing, test the new service and plan how you’ll make calls during a power cut or internet outage.
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Port your number to us
We’ll check whether we can transfer your number, prepare the paperwork and agree a porting date with your current provider. Don’t cancel your phone service before the transfer. Read how number porting works and allow time for your request to be processed.
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Test the switch and confirm what has ended
Check incoming and outgoing calls, broadband and connected equipment. Porting may automatically end the old line service, so confirm this with your previous provider. Only cancel remaining services once you know they’re no longer needed, and check any notice periods or termination charges.
Questions
PSTN and ISDN switch-off FAQs
When is the PSTN switch-off?
BT’s PSTN retirement is scheduled for 31 January 2027. Openreach is withdrawing the affected analogue and ISDN line services by that date, but your provider may move you earlier. The original December 2025 deadline was extended, which is why older guides refer to a 2025 switch-off. Arrange your migration with your provider rather than waiting until the final day.
Is the BT landline switch-off the same as the PSTN switch-off?
These phrases usually describe the same retirement of BT’s traditional phone network. It affects customers of other providers using Openreach’s affected line services too. Providers operating separate networks have their own migration plans, so check your dates directly with your provider. Digital landline services will continue to be available.
Can I keep my landline number?
You can usually keep your existing number by porting it to your new service. We’ll check whether we can transfer it to Dial 9 and handle the request with your current provider. Keep the old service active until the transfer completes and agree the broadband arrangements before starting the port.
Does the copper phone line switch-off mean I need full fibre?
No. PSTN retirement and the replacement of copper cables are different changes. Where full fibre isn’t available, services such as SoGEA can provide broadband over existing copper without an analogue phone service. Your broadband may still need to be migrated, so ask your provider which option is available and suitable for your business.
Will switching my landline affect my broadband?
It can. If your broadband depends on the same line or package as your phone service, porting the number or cancelling the line may stop the broadband too. Confirm the migration plan with both providers before placing a porting request, and arrange any replacement connection first.
Will VoIP work during a power cut or internet outage?
Your router, phone and other network equipment need power, and VoIP needs a working connection. Plan suitable battery backup and alternative connectivity, or a mobile with reliable coverage, for essential calls. Tell your provider if you depend on the landline for emergency calls. See our emergency calling information before switching.
What about my alarm, card terminal or fax machine?
Check every device with its supplier before the line changes, including telecare alarms and lift phones. Some equipment may work with an approved digital connection; other devices need an upgrade or replacement. Don’t assume an adaptor makes an alarm compatible. Have essential equipment tested as part of the migration. For fax, consider whether an online fax service meets your needs.
How long does switching to VoIP take?
Account setup and number transfer are separate steps. Porting can take days or weeks depending on the number and complexity of the request; broadband installation and equipment changes may take longer. Check our number porting lead times and plan around a confirmed transfer date.
Can I receive business calls on my mobile?
Yes. You can use Dial 9 Anywhere with Business Phone to make and receive calls over Wi-Fi or mobile data. If you only need incoming calls sent to a mobile number, take a look at our call forwarding service. We’ll check number porting separately if you want to keep an existing landline number.
Will VoIP cost more than my current line?
It depends on your current service and what you need. Compare the total cost of subscriptions, calls, broadband, equipment and any exit or transfer charges. VoIP can reduce costs, but savings aren’t guaranteed. Our Business Phone pricing and SIP trunk pricing help you compare the options.
What happens if I don’t switch before the deadline?
You risk losing service or being moved to a limited temporary voice service that may not support your current features or connected equipment. Don’t rely on an automatic migration or emergency fallback. Contact your provider now to agree a suitable replacement and transfer date.
Last reviewed: 18 September 2026. Sources: Openreach and Ofcom.
Get your business ready for the PSTN switch-off.
Talk to Dial 9 about a digital phone service that fits your business. We’ll help you choose between Business Phone and SIP trunks, check your number transfer options and plan your next steps.
Alternatively, give us a call on 0330 088 0900 or drop us an e-mail
