The PSTN switch-off: what your business must do before January 2027
The UK’s analogue phone network, the PSTN, switches off on 31 January 2027. From that date, traditional phone lines and ISDN circuits simply stop working. If your business still has analogue lines anywhere, and many do without realising it, the time to migrate is now, while engineers and installation slots are still easy to book.
What is actually happening
The PSTN (public switched telephone network) is the copper-based analogue network that has carried UK phone calls for decades. It is old, increasingly expensive to maintain, and Openreach is retiring it. ISDN2 and ISDN30, the digital services that run over the same infrastructure and power many office phone systems, are going with it.
Openreach stopped selling new analogue lines back in 2023. The January 2027 date is the hard stop: after that, services on the old network cease.
It’s not just your phones
The obvious impact is on telephony: if your office phone system connects via analogue or ISDN lines, it needs replacing or re-connecting via VoIP. But the switch-off catches businesses out because so much else quietly runs over analogue lines:
- Intruder and fire alarms that dial out to monitoring centres
- Door entry and gate systems
- Lift emergency phones (a legal requirement to keep working)
- Payment terminals on older phone-line connections
- Franking machines and fax lines
- CCTV and building management systems with dial-out alerts
Every one of these needs identifying and either upgrading to a digital-ready version or moving to an alternative connection. Finding them all is exactly the sort of job an audit is for.
What to move to
Voice moves to VoIP (hosted telephony), where calls travel over your internet connection. Done properly, it is cheaper and far more capable than the system it replaces: call menus and routing, voicemail to email, softphone apps so staff can take office calls on laptops and mobiles, and licences you can add or remove as headcount changes. We provision hosted telephony on Gamma’s Horizon platform, one of the UK’s largest business VoIP networks, as part of our connectivity and telecoms service.
Broadband moves to all-digital products, typically full fibre (FTTP) or SoGEA where fibre hasn’t reached yet. Because VoIP depends on your connection, the two moves are best planned together: there is no point putting your phones on a line that can’t carry them at busy times.
How to prepare, step by step
- Audit every line. List every analogue and ISDN service in the building, including the non-phone equipment above. Your phone bill and a site walk-round usually surface lines nobody remembered.
- Check your connectivity. Confirm your broadband has the bandwidth and quality for voice, and upgrade it first if not.
- Choose the replacement phone system. For most SMEs that is hosted VoIP with a monthly per-user licence rather than new hardware in a comms cupboard.
- Migrate the awkward stuff. Alarms, lifts and payment devices need coordinating with their own providers. Start these early: they have the longest lead times.
- Port your numbers. Your existing numbers move with you. Porting is routine but needs scheduling so there is no gap in service.
Don’t leave it until late 2026
The riskiest position is doing nothing until the deadline looms. As January 2027 approaches, installation lead times will stretch, and a rushed migration is how businesses end up with dead alarm lines or lost numbers. Migrating early costs nothing extra, and most businesses come out of it paying less per month than they did for the old lines.
Book a consultation and we’ll audit your lines, flag everything the switch-off touches, and plan a migration that happens on your schedule rather than Openreach’s.