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PSTN Switch-Off

As the UK finalises its transition from analogue PSTN (Public Switched Telephone Network) to IP-based networks, traditional phone and broadband lines are being replaced with smarter, digital solutions. This change directly impacts fire & security applications, telecare systems and lift alarms as well as any devices reliant on analogue connections. It is essential for businesses and users to upgrade to mobile or IP-compatible technologies, or risk service failures.

The PSTN switches off in:

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What is the PSTN Switch-Off?

The PSTN Switch-Off marks the completion of the project to transition the UK to an all-digital communication infrastructure, with analogue phone services to be fully phased out by 31st January 2027. As part of this upgrade, traditional telephone sockets are being replaced with Smart Routers to better support today’s consumers, their smart devices and apps.

So far, over 14 million phone lines have been upgraded, with Openreach estimates another 1.5 million still to be completed. By 31st January 2027, the digital transformation project will be complete, impacting millions of premises and requiring upgrades to maintain service continuity. CSL is here to guide you through every step, offering solutions to ensure uninterrupted, compliant connectivity.

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Preparing you for the PSTN Switch-Off

As the switch-off progresses, it’s essential to understand the impact on your systems that rely on analogue connections. We’re here to support you through every step, keeping your services running smoothly. Here are the basics:

When?

The full PSTN withdrawal and closure of all analogue phone lines will be completed by 31st January 2027.

Who is affected?

Any premises using PSTN for phone, broadband, or critical services like fire and telecare alarms will need to upgrade.

What do you need to do?

Work with CSL to future-proof your systems, ensuring continuity as the UK transitions to IP networks.

Our Futureproofed Solutions

To keep your systems connected well beyond the PSTN Switch-Off, solutions must go further than a like-for-like replacement. Our solutions are designed to future-proof your critical connectivity, with dual-core resilience and increased reliability as standard. Here’s an overview of how each can help.

rSIM

Switching from PSTN to mobile connectivity provides the opportunity to go from single, to dual-core resilience. rSIM is the world’s first truly resilient and intelligent SIM card. It constantly monitors connectivity. If the connection is lost, rSIM uses patented technology to actively switch profiles to maximise uptime and minimise downtime. rSIM effectively upgrades any single-SIM device to dual-SIM technology.

Dual SIM

Where devices already have 2 SIM slots available, CSL’s partnerships with all leading Mobile Network Operators (MNOs) means we can provide the ideal bundle, including two SIMs from two different networks for a single device. This also provides dual-core connectivity, meaning if one network experiences an outage or coverage gap, the device can fall back to the second SIM automatically, keeping critical data flowing without manual intervention.

Routers

Our Routers provide instant, resilient 4G connectivity, connecting to CSL’s private mobile APN network, establishing secure internet connectivity on sites where wired broadband is either unavailable, impractical, or slow. For enhanced reliability, CSL offers a dual-SIM variant that leverages two separate mobile providers, ensuring the highest possible availability over a mobile connection.

Outpost

Our fully managed, high-performance solution for rapid deployment of secure, resilient mobile broadband. Featuring industrial-grade routers with multiple 4G/5G modules and advanced SDN failover, it delivers ultra-fast, uninterrupted connectivity for critical operations – even in remote or complex environments.

VoiceLink

VoiceLink converts analogue PSTN data and calls to 4G VoLTE, allowing your legacy systems to stay connected as the PSTN network phases out, reducing costly equipment replacement needs. With a built-in battery backup, VoiceLink remains operational for hours during power outages, ensuring uninterrupted service for critical systems like lift alarms and emergency lines.

Alarm Signalling

We’ve helped thousands of Installers upgrade hundreds of thousands of PSTN-reliant devices to future-proofed and All IP-ready solutions. Our advanced alarm signalling solutions provide reliable, monitored connectivity, helping organisations protect people and assets while meeting strict regulatory standards.

PSTN Switch-Off FAQs

Got questions about the PSTN switch-off? Below we’ve answered the most common questions from businesses, facilities managers, and alarm installers preparing for the 31 January 2027 deadline: from what’s affected to how to migrate without disruption.

Openreach is retiring the UK’s copper-based PSTN network by 31 January 2027. After this date, services still running over analogue phone lines – including alarm signalling, telecare, and lift alarms – will stop working unless they’ve been migrated to a digital or mobile alternative. CSL’s IP and IoT connectivity solutions let you migrate ahead of the deadline rather than react to it.

Any alarm system that relies solely on a PSTN line to signal to an Alarm Receiving Centre (ARC) will stop working once the line is withdrawn. Dual-path systems that use PSTN as a backup will lose that redundancy, which can leave sites without a verified fallback path. Upgrading to CSL’s Alarm Signalling over IP or mobile connectivity keeps both the primary and backup path live after the switch-off.

Yes, telecare pendants, lift alarms, and emergency help points that use analogue phone lines are directly affected, not just office phone systems. These are often overlooked because they’re managed separately from IT and telecoms, which is why housing associations and lift operators are being urged to audit every analogue-connected device on site, not just phone extensions.

Insurers may not recognise a signalling path that no longer reaches the ARC as compliant cover, which can put a site’s insurance validity at risk after the PSTN switch-off. This is a commercial as well as a technical issue – building owners and facilities managers should treat the January 2027 deadline as a compliance deadline, not just a connectivity one. CSL can help you evidence a compliant migration path ahead of any insurer review.

You’re affected if any device on site – a fire panel, alarm signalling device, telecare base station, lift alarm, payment terminal, or PBX – connects through a traditional phone socket rather than the internet or a mobile network. Many organisations don’t realise how many “hidden” analogue devices they have until they audit their sites, which is the first step CSL recommends before the January 2027 deadline.

Single-path signalling relies on one connection method (often PSTN) to reach the ARC, so it fails completely once that line is withdrawn; dual-path signalling uses two independent routes, such as IP and mobile, so one continues working if the other is disrupted. Moving to a dual-path solution like CSL’s before the switch-off avoids a hard cut-off and gives you a tested backup route.

Yes, most sites can migrate to IP or mobile-based alarm signalling and connectivity in a phased way, site by site or system by system, without a full shutdown. Migrating early also avoids the risk of engineer and hardware shortages as the deadline approaches, which is expected to affect anyone who waits until late 2026 or early 2027.

CSL provides IP and mobile-based alternatives – including Alarm Signalling, VoiceLink, IoT SIM and IoT Router connectivity, and rSIM – that replace a PSTN connection with a resilient digital path to your ARC or monitoring service. These are designed as drop-in replacements for legacy signalling equipment, so most installations don’t require rewiring or new sockets.

Discover how businesses and industries are preparing for the PSTN Switch-Off

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Retail & Hospitality

How Whitbread future-proofed life safety across the UK’s largest hotel estate

850+ live hotels, millions of guest stays every year, and a PSTN deadline that couldn't move – Whitbread needed a connectivity partner who understood what was at stake.

Utilities

PSTN Cessation and Electricity Utilities: Protecting Substations, Telemetry & Operational Voice

The Imperative: The UK's PSTN switch-off on 31 January 2027 isn't just a telecoms deadline; it's a resilience deadline for every electricity operator still relying on copper for substation alarms, telemetry, or operational voice. The uncomfortable truth: the infrastructure you depend on during fault conditions is the same infrastructure being withdrawn – and with PSTN incident rates climbing as the network winds down, waiting is no longer a neutral choice.

Building & Security

Broadband, 4G failover and the PSTN switch-off: why the second path has to be independent

Replacing an analogue line with a digital connection removes the site’s reliance on the PSTN. It does not, by itself, prove that the connected equipment will continue to work, or that the new connection has a second route available if it fails. A second path removes a dependency only where it does not share the failure conditions of the first. CSL Broadband and the CSL Router provide fixed-to-cellular diversity, and rSIM® and DualCore® resilience extend resilience and independence to the mobile core.

Building & Security

January 2027 PSTN switch-off: what critical-device owners need to check now

The UK’s PSTN switch-off is no longer a distant telecoms upgrade. It is an operational deadline for any organisation that still relies on alarms, lift lines, telecare devices, door-entry systems, payment terminals, emergency phones, intercoms or monitoring equipment connected to analogue phone lines.

Building & Security

PSTN Switch-Off: Is Your Emergency Voice Infrastructure Ready?

PSTN switch-off is driving urgent upgrades for lift alarms, help points and EVC systems. Learn why 4G/VoLTE matters and how VoiceLink provides a retrofit path with commissioning and compliance testing.