Free tool

PSTN Switch-Off Checker

Answer 5 short questions about your phone, broadband and equipment. Get a personalised answer on whether the 31 January 2027 PSTN switch-off affects you, what specifically stops working, and the replacement options ranked by fit.

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We use this for regional context only. We do not store it.

The one-line summary

From 31 January 2027, no voice call can be delivered over the UK's traditional copper telephone network (PSTN). Openreach is migrating exchanges area by area through 2026 and 2027. If you have anything plugged into a copper line, plan a replacement before your local exchange goes.

Most fibre broadband customers move to Digital Voice from their existing ISP. Households and businesses that want to keep an analogue handset, or that do not have reliable broadband, typically need a hardware-based alternative like ONSIM Landline Replacement, which keeps their existing phone working over the mobile network.

Alarms, telecare and lift emergency phones are a separate problem and need to be dealt with separately. They signal by sending tones down the line, and those tones are unreliable over any digital or mobile voice path, so replacing the line does not fix them. Alarm panels need a signalling module from your installer, telecare users need a digital alarm unit from their telecare provider or council, and lift phones need an EN 81-28 compliant solution from your lift contractor. Start those conversations now, not in January 2027.

The main replacement options

Analogue-first

ONSIM Landline Replacement

Plug your existing analogue phone into the ONSIM box, calls run over the ONSIM mobile network. No broadband needed. Voice calls only, not for alarms, telecare or lift phones. £115.20 box + £12/mo inc VAT.

See ONSIM Landline Replacement →

Mostly inbound

ONSIM Virtual Landline

Keep a UK landline number that rings your mobile. No new hardware. Ideal if the landline is mainly for inbound calls. From £5/mo + VAT.

See ONSIM Virtual Landline →

Broadband-based

Digital Voice from your ISP

BT Digital Voice, Sky Talk, Virgin Media digital voice, etc. Straightforward if you have fibre and no analogue kit. Requires broadband and mains power to be up for calls to work.

Bridge measure

BT EVAc

Emergency Voice Access, a free BT service for vulnerable customers as a time-limited bridge during migration. Not a permanent answer. See our EVAc vs Landline Replacement page for the trade-offs.

EVAc vs Landline Replacement →

Frequently asked questions

About the PSTN switch-off and this checker

What is the PSTN switch-off?

The UK's traditional copper telephone network (PSTN) is being permanently withdrawn. The hard deadline is 31 January 2027. From that date, no analogue voice service delivered over copper will work. Openreach is migrating exchanges area by area from 2026 onward.

When exactly is my area affected?

Openreach announces exchange-level "stop sell" dates in tranches. Your specific date depends on your local exchange. Ask your current telecoms provider for your exact migration date. The universal cut-off is 31 January 2027, regardless of local scheduling.

What is Digital Voice?

The generic name for a voice service delivered over broadband (VoIP). BT calls it Digital Voice, Sky calls it Sky Talk, and so on. It replaces the analogue landline for most fibre broadband customers, but it requires broadband to be up and mains power at the router.

What is BT EVAc?

BT's Emergency Voice Access. A free bridge service for vulnerable customers being migrated, giving them a working phone during the transition. It is a time-limited stopgap, not a permanent solution. See EVAc vs Landline Replacement for the trade-offs.

What is ONSIM Landline Replacement?

A small box that plugs into your existing analogue phone. It carries the call over the ONSIM mobile network instead of copper or broadband. No app, no VoIP, no engineer visit. Suited to households and businesses that want to keep an analogue handset working without depending on broadband uptime. It is a voice line only, and is not suitable for alarm, telecare or lift emergency signalling. From £12 a month inc VAT, plus a £115.20 box you can spread over 12 months.

What about my alarm system?

PSTN-connected alarms lose their monitoring station connection at switch-off, and swapping the line will not fix it. Analogue alarm diallers signal by sending tones down the line, and those tones are unreliable over any digital or mobile voice path, including ours. Monitored signalling also has to meet transmission time, availability and supervision requirements that a voice path cannot evidence. The answer is different signalling, not a different line: ask your alarm installer to fit a mobile or IP signalling module. ONSIM Landline Replacement is not suitable for alarm signalling and we do not support it for that purpose.

What about my telecare alarm, pendant or care line?

Treat this as urgent and speak to your telecare provider or your local council, not to a phone company. Analogue telecare uses tightly timed tones that digital voice codecs, echo cancellation and packet timing all interfere with, and the failures are silent, so the alarm appears to work until the moment it is needed. Around 1.8 million UK households rely on telecare. The replacement is a digital alarm unit that signals over its own mobile connection rather than through your phone line. ONSIM Landline Replacement is not suitable for telecare and we do not support it for that purpose.

What about my lift emergency phone?

Lift emergency phones are covered by BS EN 81-28, which places a legal obligation on the building operator to keep the line functional, and additionally requires the system to alert if the communication link fails and to support periodic automatic test calls. A standard analogue port cannot deliver that link supervision, so this needs a purpose-built GSM or 4G lift phone solution. Contact your lift maintenance contractor. ONSIM Landline Replacement is not suitable for lift emergency phones.

Can I keep my existing landline number?

Yes. Your 01, 02 or 03 number can be ported to a new service (Digital Voice, ONSIM Landline Replacement, ONSIM Virtual Landline, another provider). Number porting is a standard process regulated by Ofcom.

Is this checker legal or professional advice?

No. This tool gives general guidance based on your answers. For safety-critical equipment (alarms, lifts, medical alerts) always confirm the fix with the equipment installer. For regulated business use (FCA / PCI-DSS) confirm any new voice architecture with your compliance team.

Do you store my answers or postcode?

No. Your answers are saved in your own browser (localStorage) so you can come back and complete the check. Nothing is uploaded or logged by ONSIM. The postcode field is optional and used only for regional context in the recommendation.

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