Modern businesses are built upon many layers of technology. Buried deep within lies legacy infrastructure like the Public Switched Telephone Network (PSTN), an ageing copper architecture.
This network still underpins critical services and systems, many of which are potentially being overlooked. As the UK fully transitions to a future-proof infrastructure driven by fibre and digital innovations, the crucial question is…
How prepared are you to switch off your PSTN systems when you’re unsure what’s still running on them?
The final switch-off for all UK PSTN services is now the end of January 2027 (Vulnerable and Complex Use Cases). However, a nationwide “stop sell” has been in effect since September 2023, meaning no new PSTN-based services can be purchased. This transition is not a distant problem; it’s an immediate strategic imperative.
Is the PSTN Still Powering Critical Parts of Your Business?
Recent research reveals a concerning lack of preparedness among UK businesses. Data from [Zen Internet] shows that only 18% of small businesses and 26% of large businesses have a post-PSTN solution in place.
This highlights a significant underestimation of how deeply embedded PSTN lines are in daily operations. Dependencies like business phone lines, alarms, EPOS and PDQ machines are often deeply integrated into core systems. Failure to migrate these can result in a sudden loss of service, higher operational risk, and increased costs.
The Silent Threat: Why the PSTN Switch-Off Isn’t Just a Telecoms Problem
As UK businesses transition from copper cabling to fibre-based systems like VoIP, it’s a common mistake to assume that all legacy systems will be automatically transferred.
Systems such as lift phones, fax machines, intruder alarms, and other security systems are frequently forgotten. Often, these sit outside the IT department’s direct line of sight – usually managed by facilities departments or legacy vendors.
The impact of disruption can affect safety, compliance, service delivery, and brand trust. Don’t just remove legacy systems; preserve service continuity, safety, and brand integrity by planning your migration now.
Who’s Exposed & Why They Might Not Know It
Public sector organisations, like the NHS and local authorities, are among the most at risk due to their complex estates and often decentralised infrastructure. A study revealed that 44% of NHS Trusts have no formal strategy for the switch-off, despite having thousands of PSTN lines. Other businesses at high risk include:
- Organisations with legacy contracts: Businesses with long-standing suppliers managing their comms infrastructure may have limited visibility.
- Businesses that haven’t conducted a recent audit: Any organisation that hasn’t performed a line-by-line audit or centralised its communications oversight in the last 5 years is likely to have unknown exposures.
Forward-thinking organisations are working with integration partners who understand both the technical and operational implications of these legacy disconnects. Partners like Maintel specialise in navigating the full transition from copper to cloud.
Why Waiting Is the Worst Option
As our Head of Network & Carrier Services, Andy Set, commented:
“One of the longest delays in this transition is the time it takes to install and test new All-IP services. Although the final deadline is January 2027, the process of auditing, procuring, and migrating can take months. Issues like engineer availability and regulatory sign-off can cause significant delays and carry major financial or legal consequences. Procrastinating is not an option.”
For those with highly specialised analogue equipment, a temporary solution known as a ‘Pre-Digital Phone Line’ (PDPL) may be necessary. This service emulates an analogue line on the new digital network, but it is an interim fix, not a long-term strategy. Identifying the need for such a solution early is critical to avoid bottlenecks. (NB: The deadline for ordering PDPL is the end of August 2025)
Your Hidden PSTN Exposure: 4 Red Flags to Watch For
As a starting point, answer these four critical questions:
- Do you know exactly how many PSTN lines are still active across your entire estate?
- Do you have a definitive list of the services and devices tied to them?
- Do you rely on vendors or departments outside of IT to manage older systems (e.g., alarms, lifts, intercoms, CCTV)?
- Do you have sites that haven’t been fully reviewed or audited for connectivity since before 2020?
If you answered “no” or “I don’t know” to any of these, you are likely at risk.
Where Leaders Are Starting: Maintel’s Guide to Action
The first step is to understand your unique position. We recommend taking our interactive self-assessment to find out where you are in your PSTN journey.Next, speak to your telecoms provider for further information and guidance. We’re here to guide you through the entire process, from discovery through to a secure, managed migration.
The PSTN switch-off isn’t a one-time fix; it should be a phased transition across your entire business estate and infrastructure. Our role is to help you navigate the risk and ensure everything is accounted for. Because when systems are invisible, they’re often ignored – until they fail. We don’t just replace lines; we ensure nothing critical slips through the cracks.
Try our PSTN Assessment Calculator here
If you would like us to help you on your PSTN journey, you can contact us through our dedicated PSTN form here.