The UK’s Copper Phone Network Is Being Switched Off – Is Your IoT Estate Ready?

TL:DR

• Openreach is shutting down the UK’s copper PSTN network for good, with the final switch-off locked in for January 31, 2027 – less than six months away.
• Hundreds of thousands of business lines, an estimated 350,000 or more by some counts, still rely on legacy copper to power elevators, alarms, POS terminals, and telemetry systems.
• Cellular IoT connectivity, including VoLTE voice and low-power LTE-M/NB-IoT, offers a more resilient replacement than a simple IP swap, one that keeps working through power outages.

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If your business still relies on traditional analogue phone lines or ISDN connections for things like alarm systems, elevators, or payment terminals, time is now officially running out. Openreach is retiring the UK’s legacy Public Switched Telephone Network (PSTN), and the deadline is under six months away.

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What’s Actually Happening

For over a century, PSTN has been the backbone of UK telecom: copper wires carrying voice and data between buildings and exchanges. Openreach (part of BT Group) is decommissioning that network entirely and moving all services onto an all-IP, internet-based infrastructure.

This isn’t unique to the UK, either, as similar switchovers are underway across Europe. Germany, the Netherlands, Estonia, and Norway have already completed their transitions to all-IP, and countries including Sweden, Spain, France, and Denmark are in the midst of their own migrations. The direction of travel is the same everywhere: copper is going away.

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The Key Dates

• September 2023 – National Stop Sell. Openreach stopped selling new PSTN and ISDN lines altogether. If you need a new line today, it’s already IP-based.
• December 2025 – Industry migration target. This soft deadline (meant to get customers switched over ahead of a last-minute bottleneck) has already passed. If your organization hasn’t already begun migrating, you’re behind where the industry wants you to be.
• January 31 2027 – Full switch-off. This was originally planned for 2025 but was pushed back to give vulnerable users and businesses (particularly those relying on telecare devices) more time to migrate safely. After this date, analogue services stop working entirely.

That leaves fewer than six months. This is no longer a “provisional” date sales teams should hedge on, either: Openreach has confirmed that all technical barriers to migration, including protections for vulnerable telecare users, have been resolved, and the deadline is now locked with no extension planned. For anyone with a distributed estate of hardware – alarms, elevators, meters – that’s an extremely tight window for a physical rollout, and time to plan a phased migration is running out fast.

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The Scale of What’s Left to Migrate

This isn’t a hypothetical risk for a small number of stragglers. Openreach’s own data puts the scale of the remaining task in perspective: an estimated 2.8 million lines are still on the PSTN network and need to migrate, more than half a million of which serve business premises. A more recent estimate suggests around 1.5 million lines remain on legacy copper, including roughly 350,000 business premises – a gap Openreach has explicitly flagged as a “blind spot” in its latest push to get organizations moving.

On the safety-critical side specifically, there’s reassurance that the migration path is genuinely workable: Openreach’s “Prove Telecare” service has already safely migrated more than a thousand customers using fixed-line telecare and health-alarm devices onto digital voice services, with no reported disruptions to service. The technology and process for even the most sensitive use cases has been proven – all that remains is getting organizations to act.

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Who This Actually Affects

The switch-off matters most for organizations with devices that were designed decades ago around a permanent analogue line, including:

• Lift and elevator emergency phone lines
• Fire and security alarm dialers
• Telecare and social alarm devices
• Older point-of-sale (POS) terminals
• Legacy utility metering and telemetry systems
• Building management systems (BMS) and HVAC controls

It’s worth separating these into two groups, because the fix looks different for each. Elevator lines and alarm dialers are typically voice-dependent – they need to place an actual call in an emergency – whereas POS terminals, meters, and BMS/HVAC systems are usually data-dependent, requiring reliable connection rather than a phone call.

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Why A Straight IP Swap Isn’t Always the Right Answer

The obvious fix is to replace the line with a standard fibre IP or IP-based broadband connection, and for a lot of use cases, that works fine. For anything safety-critical or physically hard to reach, however, it introduces new problems:

• Fixed-line installation is often complex or expensive for equipment like in-elevator phones, especially in older buildings.
• A broadband line goes down when the power does, unless it’s paired with a separate battery backup, often an added cost and complexity for equipment in hard-to-reach locations, which is exactly the retrofit problem this migration is meant to solve.
• Devices in remote or hard-to-wire locations (meters, remote sensors) may not have a practical fixed-line path at all.

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Where Cellular IoT Connectivity Comes In

Cellular connectivity – particularly 4G/LTE-M – is increasingly the preferred alternative for PSTN replacement, for a few reasons:

Independence from fixed-line infrastructure. A cellular connection doesn’t care whether there’s a phone line or broadband router nearby. This makes it far faster to deploy, particularly across a large or geographically varied area.

Resilience during outages. Cellular gateways built for safety-critical use such as elevator lines and alarm dialers are typically designed with battery resilience in mind from the outset, and cellular networks themselves are built with their own backup power as standard – so a local power cut is less likely to take out the whole path the way it can with fixed-line infrastructure.

Voice that actually works. Elevator emergency phones and alarm dialers need to carry an actual voice call, not just data – which means VoLTE, not just a SIM with a data plan. Soracom’s Air RTC Gateway takes a device’s cellular voice over VoLTE and routes each call, by SIM and device identity, straight to a contact centre, VoIP provider, or AI agent – no voice application development required.

Low-power options for low-data devices. For use cases like utility meters and BMS/HVAC sensors, which don’t need much bandwidth but do need to run for years on a single battery, LTE-M and NB-IoT are purpose-built. They offer the reliability of cellular without the power draw of a full broadband replacement.

In practice, that means cellular connectivity can serve as either the primary connection for these devices going forward, or as a resilient secondary backup layered onto an IP line – giving organizations redundancy they didn’t have with PSTN in the first place.

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The Takeaway

The PSTN switch-off isn’t a distant regulatory footnote: Openreach stopped selling new lines back in 2023; the industry’s own migration target has already come and gone; and the final January 2027 deadline is now confirmed with no extension. With under six months left and hundreds of thousands of business lines still unmigrated, the practical work of planning and deploying replacements needs to start immediately for any organization with elevators, alarms, POS terminals, or legacy telemetry still running over copper.

The good news is that this migration doesn’t have to mean a like-for-like swap. Done well, it’s an opportunity to move to connectivity that’s more resilient than what it’s replacing – able to keep working when the power goes out, and easy to deploy at scale without waiting on a fixed-line installation.

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Want to know if your devices are affected, or how to plan a migration path – including voice routing for elevator and alarm systems – before the 2027 deadline? Get in touch with our team.