Could your fire alarm become a silent alarm?
On 31 January 2027, the UK’s traditional copper telephone network, known as the Public Switched Telephone Network (PSTN), will be permanently switched off. Businesses that still rely on legacy signalling equipment may lose their ability to transmit fire alarm activations to an Alarm Receiving Centre (ARC).
For many organisations, this isn’t simply an IT or telecommunications upgrade – it’s a life-safety, compliance, insurance and business continuity issue. If your monitored fire alarm can no longer communicate with an ARC, your system could effectively become a silent alarm, potentially creating a dangerous gap between fire detection and emergency response.
With Openreach reporting that approximately 350,000 UK businesses were still using legacy PSTN services during 2026*, many organisations remain exposed to this risk.
What does the PSTN switch-off mean for your business?
Not all businesses are connected to an ARC, as it’s not a legal requirement. However, 24-hour fire alarm monitoring for sites that require it, such as commercial offices, rural agricultural sites, or production factories, will lose that business protection if they haven’t upgraded to a digital line by the time the PSTN switchover is complete.
If your premises relies on monitored fire alarm signalling, the potential risks include:
- Loss of monitored alarm communication
- Delayed emergency response
- Non-compliance with insurance requirements
- Increased business interruption risk
- Reduced protection for people, property and critical assets
- Unplanned upgrade costs if action is left too late
How do I know if my fire alarm uses PSTN?
Many businesses are unaware that their fire alarm monitoring still relies on a PSTN line. Has your maintenance provider discussed PSTN migration with you? If you’re unsure, ask yourself the following questions:
- Does your fire alarm send signals to an Alarm Receiving Centre (ARC)?
- Are you paying for a dedicated telephone line solely for alarm monitoring?
If the answer is yes to any of the above, it’s worth arranging a fire alarm system review before the January 2027 switch-off.
Who is liable and what will not acting swiftly cost?
When a business property experiences a fire or break-in, it’s the business owner and responsible person facing liability. From a health and safety perspective, protecting your employees and site visitors should be the number one priority, addressing the PSTN switch-off as soon as possible.
The insurance policy should be thoroughly checked to assess the business risk and all financial ramifications of not acting now.
Businesses should also check whether monitored fire alarm signalling is referenced within their insurance policy conditions. Some insurers require monitored alarm systems as part of the agreed risk controls for a property.
To accelerate PSTN – originally planned for switch-off December 2025 – Openreach announced a three-phase price increase to business line rental charges. This included a 20% increase on April 1 2026, a 40% increase on July 1 and a final 40% increase on October 1 2026.
Speaking in July, after the second round of price increases, James Lilley, Director of All-IP at Openreach, stressed the importance of switching sooner, rather than later, stating:
“The consequences go beyond technical issues – they can lead to lost revenue, operational difficulties and a poorer experience for customers. The message is simple: act now.”*
As a final temporary measure, Openreach is activating an Emergency Voice Access (EVAc) for emergency services only once the deadline has passed.
What standards must your new fire alarm system meet?
The objective is to ensure alarm activations continue reaching the ARC quickly and reliably, even if one communication path fails. For many businesses, this will mean replacing a PSTN communicator with an IP, 4G or 5G-compatible signalling solution.
As part of the recently updated standards, BS5839:1-2025 requires dual path monitoring for fire alarms, where the communicator is graded at DP4 using IP and GPRS paths.
However, circumstances where IP is unavailable, a variation can still be written against the British Standard and a DP3-graded communicator, signalling via two independent GPRS paths, can be used.
BS 5839-1:2025 highlights the importance of response time for any signalling, with two key additions, 14.17 and 14.18, which state:
- 14.17 For Category L systems, in the event of a fire alarm signal, an indication should be received at the ARC within a maximum of 90 seconds; a catastrophic failure of the transmission system (whereby no alarm signals can be transmitted) should be indicated at the ARC and the CIE within 3 minutes.
- 14.18 For Category P systems, in the event of a fire alarm signal, an indication should be received at the ARC within a maximum of 2 minutes; a catastrophic failure of the transmission system (whereby no alarm signals can be transmitted) should be indicated at the ARC and the CIE within 31 min.
In the long run, it puts assets and people at greater risk should a fire start.
The step-by-step PSTN migration roadmap for business owners & facility managers
- List every site where you believe you may have a fire alarm connected to a copper line.
- If not done so already, arrange a fire risk review to evaluate the existing system with your current maintenance provider, or a chosen BAFE-accredited alternative provider.
- Check that the system adheres to your insurance policy to ensure compliance and that the agreement will not be void if fire damage to the property or loss of life occurs on site.
- Replace your single-path analogue system or one part of dual-path with a 4G or 5G signal, the most reliable method for ARCs. Once commissioned, check with the ARC that the signal is picked up when activated within the latest code of practice maximum timeframe.
- Ensure all updates are documented in the logbook as per BS5839:1-2025 standards and notify your insurance company of the upgrade.
Don’t leave it until the last minute: why you must act now
The first indication of the PSTN switch-off plan was announced in 2017. It’s taken nearly ten years to get to this point where businesses move towards the expected digital age of phone lines and in tandem security systems.
It’s not expected that all alarms will stop working at the 31 January 2027 deadline, but it’s also not worth the risk of finding out there is a silent alarm signal not transmitting to the ARC.
With that in mind, the final quarter of 2026 is the perfect time to act.
Entering the final stages of the migration programme, engineers will be booking up rapidly, with a backlog of companies looking to switch over one or multiple alarms to a digital upgrade.
Businesses with multiple sites should begin planning upgrades as early as possible to avoid engineering delays and last-minute compliance concerns.
Budgeting for all work that needs to be done, as well as updating your insurance policy to meet business and liability compliance is of paramount importance.
Book your fire alarm PSTN readiness review
Not sure whether you have a copper line network in place linked to your fire alarm system?
Before the switch-off, we’re offering a free, no-obligation readiness review. We’ll assess whether your existing alarm signalling relies on PSTN, review your monitoring arrangements, discuss insurance considerations and recommend the most suitable migration path. Use our contact form to arrange your Readiness Review.
*OpenReach (31 July 2026). ‘Openreach warns businesses: just six months left before the UK’s old phone network is switched off‘ – Press Release.
Frequently Asked Questions (FAQs)
What is PSTN?
PSTN stands for ‘Public Switched Telephone Network’, with the copper telephone line first installed in the 19th century. Openreach stopped installing copper lines in September 2023.
When is the official switch-off?
The PSTN switch off is set for 31 January 2027. It was initially planned for December 2025, but an extension of the date was made to allow businesses more time to switch over to digital networks running on an Internet Protocol (IP) address.
Do UK businesses need to install fire alarms that are hardwired?
The Regulatory Reform (Fire Safety) Order 2005 states that UK businesses must provide an “appropriate fire detection and warning system,” instead of a specific type of wiring.
What happens after the deadline if your alarm remains analogue?
Your business may be placed on an EVAc, meaning higher rental charges that are voice activations only for emergency services. Therefore, it’s highly likely your alarm signal to the ARC will still be silent.
