PSTN Switch-Off 2027: The Complete Guide for UK Businesses

What is the PSTN switch-off?

The Public Switched Telephone Network (PSTN) is the UK's traditional copper telephone infrastructure — the same network that has carried business and residential phone calls for over a century. BT Openreach has confirmed it will permanently retire this network on 31 January 2027.

After that date, every device that relies on a traditional phone line — desk phones, fax machines, alarm diallers, card payment terminals, CCTV systems, lift phones — will stop working unless it has been migrated to an internet-based alternative.

The ISDN network, which many businesses use for their phone systems and higher-capacity lines, is being retired at the same time.

Which businesses are affected?

Your business is affected if you currently have any of the following:

• A traditional BT business landline (analogue phone line)
• An ISDN2 or ISDN30 circuit connected to a PBX phone system
• Broadband delivered over an old FTTC line with a bundled phone line
• A fax machine connected to a phone line
• An intruder or fire alarm that dials out over a phone line
• A card payment (PDQ) terminal that uses a phone line
• A CCTV system with a phone line connection
• A lift with an emergency phone connected to a landline
• A door entry system connected to a phone line

Key dates

Your three migration options

Every business has three main routes for replacing their traditional phone service. The right one depends on your existing hardware, budget, and how your team works.

Option 1: App on your smartphone or computer

The quickest and cheapest option. A VoIP app on your existing smartphone, tablet, or computer replaces your desk phone entirely. Your business number transfers to the app — calls come in and go out exactly as before, but over your internet connection instead of a copper line.

Best for: Businesses where staff are already mobile, teams that work from multiple locations, or any business looking to reduce hardware costs.

Cost: From £8.95/user/month on GoYap's 24-month contract, or £9.99 on a 30-day rolling basis.

Option 2: Keep your existing analogue phones

If you want to keep your existing handsets — whether that's a traditional cordless phone on a desk or a multi-handset office setup — you can. You'll need either a new broadband router with a built-in phone port (FXS port) or a small ATA (Analogue Telephone Adapter) device that connects to your existing router.

Important: Standard broadband routers do not have phone ports. Even routers that technically support FXS ports are difficult to configure for VoIP remotely. We supply and configure either the router or ATA as part of your migration — any standard analogue handset then plugs straight in and works exactly as before.

Best for: Businesses that want minimal disruption and are happy with their existing handsets.

Option 3: New VoIP desk phone or cordless handset

A modern VoIP desk phone or cordless handset connects directly to your broadband router via ethernet or Wi-Fi. Call quality is typically better than traditional PSTN calls, and the phones support features like call recording, call forwarding, and voicemail-to-email.

Best for: Businesses wanting to upgrade their hardware as part of the migration.

Cost: From £12.95/user/month including handset rental on a 36-month contract.

Do I need new broadband?

VoIP calls run over your internet connection, so a reliable broadband line is essential. Most businesses already have broadband and it will work fine for VoIP — but there are two scenarios where you may need to take action:

Scenario 1: You have FTTC broadband bundled with a phone line

If your current broadband comes as part of a package that includes a traditional phone line (this is common with older BT and TalkTalk business packages), that product will be discontinued as part of the switch-off. You'll need to migrate to a standalone broadband product — either SoGEA (which is FTTC without the phone line) or ideally full fibre FTTP if it's available at your address.

Scenario 2: Your broadband isn't fast or reliable enough for VoIP

VoIP calls use relatively little bandwidth — roughly 100Kbps per concurrent call — but they're sensitive to latency, jitter, and packet loss. If you have a slow or unreliable connection, call quality will suffer. We test your connection as part of your migration quote and recommend an upgrade if needed.

Special services to check

The following services all commonly use PSTN connections that many businesses aren't aware of. Each needs to be assessed and migrated separately from your main phone system:

Power resilience — an important consideration

Traditional PSTN phones could work during a power cut because they were powered directly from BT's exchange. VoIP phones are powered by your router, which needs mains electricity. If the power goes off, your phone system goes offline.

For most businesses this is an acceptable risk — staff have mobile phones as a fallback. But for businesses where phone availability is genuinely critical (medical, emergency services, out-of-hours support), a UPS (uninterruptible power supply) for your router is worth considering. The GoYap mobile app also continues to work over 4G/5G during a power cut.

How long does migration take?

The timeline depends on which option you choose:

• App on smartphone/computer: Same day — account created instantly, app downloaded in minutes
• ATA adapter with existing phones: 1–2 weeks including number porting
• New broadband + voice-ready router: 2–4 weeks from order
• Full system replacement with new phones: 2–6 weeks depending on size
• Number porting: 7–14 working days in all cases

What does migration cost?

Migration to VoIP typically costs significantly less than staying on traditional PSTN lines — not more. Here's a comparison:

Frequently asked questions