Last Updated on 21 October 2026.
Remember the switch from Analogue TV to Digital/Freeview?
Well, the exact same thing is happening right now – but this time, with the UK’s phone network.
With the final 31st January 2027 deadline fast approaching, this is an urgent must-read for business owners and facilities managers. While the digital switchover affects every commercial premises, it is especially critical if you rely on remote alarm monitoring for your fire and/or intruder alarm systems.
Need to upgrade your alarm signalling before the January 2027 cutoff? Give us a bell on 01277 724 653 and we’ll be happy to help!
Here’s what we’ll be covering:
A brief synopsis of what’s happening
The communications and telecoms industry has evolved massively over the last 50 years, largely driven by our reliance on the Internet and the nationwide expansion of full-fibre broadband.
Now, the biggest telecoms shake-up in a generation is reaching its final stage: the permanent retirement of the UK’s PSTN (Public Switched Telephone Network)—part of the legacy Wholesale Line Rental (WLR) product family—and the complete transition to digital, internet-based communications known as All-IP and VoIP (Voice Over Internet Protocol).
In short, the UK has gone digital, and our traditional analogue copper phone network is being switched off for good. At the same time, mobile network operators are phasing out legacy 2G and 3G networks in favour of faster, more resilient 4G and 5G connectivity.
What is PSTN and ISDN?
PSTN (Public Switched Telephone Network) is your traditional landline that transports voice and data in an analogue format using underground copper phone lines. Amazingly, this is pretty much the same foundational way phone networks have operated since the late 19th Century!
Compare that to ISDN (Integrated Services Digital Network), which was introduced in the late 20th Century as the original high-speed digital business line—the prelude, if you like, to modern VoIP. While ISDN allowed businesses to transmit data and handle multiple voice calls simultaneously over telephone wiring, both PSTN and ISDN rely on ageing copper infrastructure that is no longer fit for the modern digital era.
Moving to All-IP and modern cellular signalling is a whole new ball game. Let’s dive into the vital questions you need answered before the final switch-off deadline…
When is the PSTN switch-off happening? (The January 2027 Deadline)
While the industry originally targeted the end of 2025, BT and Openreach extended the final switch-off date to 31st January 2027 to ensure critical national infrastructure and vulnerable users could be migrated safely. Openreach has been crystal clear: there will be no further extensions beyond January 2027.
When we wake up on 1st February 2027, traditional analogue PSTN and ISDN lines will be permanently retired. All voice calls and alarm signalling must operate over digital IP or cellular (4G/5G) networks rather than old copper wires.
Furthermore, the National Stop-Sell has already been in force since September 2023. This means telecoms providers have already stopped selling new analogue PSTN lines, and many local exchanges across Essex, London, and the South East have already completed their digital migrations.
If your business still has any legacy copper lines left on-site, you are now in the final countdown window. Leaving your migration until the last minute risks getting caught in a nationwide bottleneck of engineering demand—or worse, having your line forcibly migrated onto a restricted temporary service like Openreach’s EVAc (Emergency Voice and Access Continuity), which carries higher rental fees and does not reliably support fire or intruder alarm signalling.
Who is affected by the switch to All-IP?
This transition affects every commercial premises, school, care home, hotel, and industrial site in the UK that still has equipment plugged into an analogue PSTN socket or ISDN line.
Crucially, it isn’t just your desk phones that are affected. The PSTN switch-off impacts all “non-voice” services connected to copper lines, including:
- Monitored Fire Alarm Systems
- Monitored Intruder & Panic Alarms
- Emergency Lift Phones & Disabled Refuge Systems
- Access Control, Door Entry & PDQ Machines
Adding to the urgency for Facilities Managers was the recent closure of BT Redcare, which ceased operations in August 2025, forcing thousands of commercial buildings to find alternative alarm signalling providers. If your site has an older alarm communicator that still relies on a PSTN phone line—or an outdated 2G/3G mobile SIM—you must upgrade your signalling unit immediately.
Why is the PSTN switch happening in the first place?
The copper network is being retired for two simple reasons: obsolescence and performance. Many of the exchange components that power the UK’s PSTN network are decades old, spare parts are no longer manufactured, and maintaining millions of miles of decaying copper wire is both environmentally and financially unsustainable.
Back in the 1970s and 1980s, when fax machines and dial-up modems operated over phone lines, analogue copper was ideal. Today, in an era of cloud computing, smart buildings, and instant digital diagnostics, we have stretched ISDN and PSTN far beyond what they were ever designed to handle.
Why should I upgrade my alarm signalling now instead of waiting?
With the 31st January 2027 deadline right around the corner, acting now protects your building in three vital ways:
- Protecting Your Insurance Validity: Many commercial businesses are legally or contractually required by their insurers to maintain active, compliant fire alarm monitoring and intruder alarm monitoring (especially for Police Unique Reference Number [URN] response). If your telecoms provider switches your phone line over to VoIP/All-IP and your legacy alarm communicator fails to signal to the Alarm Receiving Centre (ARC), your building could be left completely unmonitored—invalidating your commercial insurance policy overnight.
- Lower Ongoing Costs: Legacy dedicated copper phone lines were notoriously expensive—businesses often paid hefty quarterly line rental fees to BT just to keep a single alarm dialler connected! Modern dual-path radio and IP signalling units eliminate the need for a dedicated analogue phone line, saving you money every single year.
- Avoiding the Deadline Rush: As the final January 2027 cutoff hits, thousands of unprepared businesses will be scrambling for engineers and signalling hardware at the exact same time. Upgrading during your next scheduled fire alarm maintenance or intruder alarm servicing visit saves you call-out fees and guarantees a smooth transition.
Is All-IP and Digital Signalling secure?
You might have heard rumours in the past that analogue lines were more reliable than internet-based signalling, but modern alarm communications have solved this completely. Today’s industry-standard alarm communicators don’t rely solely on your building’s broadband router; instead, they use encrypted, multi-network 4G/LTE cellular roaming SIMs paired with IP paths, backed up by dedicated battery power inside the alarm panel. Even if your building suffers a total power cut or broadband outage, your alarm signal still reaches the Alarm Receiving Centre in seconds.
What will happen to my intruder/fire alarm monitoring when the switch happens?
If we have already upgraded your system to a modern All-IP / 4G communicator (such as CSL DualCom Pro), your alarm will continue working seamlessly. The Alarm Receiving Centre (ARC) will be notified instantly whenever your alarm activates to alert your nominated keyholders, the Police, or the Fire Brigade.
However, if your alarm still relies on an old PSTN dialler or legacy copper line, it will fail.
Why? Because legacy alarm modems send analogue “tones” down a copper wire. When a phone line is converted to digital VoIP/Fibre, those analogue tones get compressed and scrambled during digital translation, resulting in communication faults, constant beeping at your control panel, or total signal failure during a real fire or break-in.
(Note: You can upgrade your alarm’s signalling device today without waiting for your IT team to change your office phone system—our modern communicators use independent wireless radio paths, meaning they don’t even need to touch your phone lines!)
Click here to learn more about our commercial fire alarm monitoring.
Click here to learn more about our intruder alarm monitoring.
Can BT help me with my alarm to make sure the monitoring works?
No. BT and Openreach engineers will not touch, reprogramme, or upgrade your fire or intruder alarm equipment. When they switch your exchange or building over to digital Fibre/VoIP, it is entirely the building owner’s responsibility to ensure their third-party life-safety and security systems have been upgraded by an accredited fire and security specialist (like WFP!).
What are my options?
For your office phone system…
- Upgrade to a cloud-based VoIP phone system: Faster, cheaper, and far more flexible for modern businesses.
- Use an ATA (Analogue Telephone Adapter): A temporary plug-in converter that allows an old handset to plug into a digital router (though replacing legacy handsets is almost always the better long-term bet).
For your fire and intruder alarm system(s)…
- Avoid “sticking plaster” analogue converters: While some providers offer Modem Capture Modules (MCMs) that try to trick an old PSTN alarm dialler into working over IP, they are not a sustainable long-term solution and often struggle with strict BS 5839-1 and insurance compliance around battery backup and signal polling times.
- Upgrade to a future-proof CSL DualCom Pro Signalling Unit (Recommended): WFP strongly recommends upgrading to CSL DualCom Pro. Available in both single-path and dual-path (IP + 4G WorldSIM radio) configurations, DualCom Pro is fully compliant with the latest fire and security standards, works independently of copper phone lines, and connects directly to our 24/7 Alarm Receiving Centre.
We have already helped hundreds of businesses across Essex, London, and the South East transition safely away from PSTN and legacy Redcare systems. If your alarm signalling hasn’t been upgraded yet, please contact our team today—we can quickly check what communicator you have on-site and schedule a seamless upgrade during your next routine maintenance visit to save you the cost of an extra call-out.
And if you aren’t yet a WFP customer, we can easily take over and upgrade your fire or intruder alarm monitoring alongside a tailored Planned Preventative Maintenance (PPM) package!
Contact us today on 01277 724 653 or request a free quote online!
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An intruder alarm system is one of the highly demanded security essential services