BT is retiring the old analogue PSTN and ISDN network for good. Every business in the UK needs to migrate before the deadline — and the clock is ticking.
The Public Switched Telephone Network (PSTN) is the UK's traditional copper wire phone infrastructure. It's been around since the 1800s. BT has confirmed it will be fully decommissioned by January 2027.
This also affects ISDN (Integrated Services Digital Network) lines — commonly used for business broadband, multi-line phone systems, and fax machines. All of it goes.
The replacement is VoIP (Voice over Internet Protocol) — calls made over a standard broadband connection, which is faster, cheaper, and far more flexible.
PSTN — traditional analogue phone lines
ISDN2 / ISDN30 — digital lines for businesses
WLR — wholesale line rental
Fax lines over analogue
VoIP — calls over broadband
SIP Trunking — business-grade internet calling
Microsoft Teams Calling — cloud phone system
Hosted / Cloud PBX — full phone system online
Alarm systems, door entry systems, CCTV lines, PDQ/card payment terminals, and lift emergency phones that run over analogue lines will also need updating.
BT stopped selling new PSTN and ISDN lines. Businesses can no longer add new analogue lines.
Openreach is switching off exchanges across the UK in waves. Some areas are already on VoIP-only infrastructure. Check now — your area may be next.
All remaining analogue lines go dark. Any business still on PSTN or ISDN after this date will lose their phone service entirely, with no fallback.
If your business uses any of the following, you need to act before the deadline. The good news is migration is straightforward — and often saves money.
Any phone that plugs into a BT wall socket and runs over a copper line — home office, reception desk, or office handset.
Fax still used in legal, medical, and financial sectors. These all run over analogue lines and will stop working.
Some older PDQ/card terminals still dial over PSTN. If yours does, it'll stop processing payments after the switch-off.
Many burglar alarms, fire alarms, and monitored security systems use analogue lines to contact monitoring centres.
Office phone systems (PBX) using ISDN2 or ISDN30 connections for multiple lines will cease to function.
Lift intercoms and emergency call points in commercial buildings commonly run over analogue lines.
Millions of UK businesses need to migrate. As 2027 approaches, installation lead times will grow and engineers will be booked out. Businesses that act now get better pricing, more choice, and a stress-free migration. Those that leave it late face higher costs and potential service disruption.
We review your current phone setup, internet connection, and any analogue-dependent systems to map out exactly what needs to change — and what doesn't.
We recommend the right solution for your size and budget — whether that's a simple VoIP swap, a full cloud phone system, or Microsoft Teams Calling.
We handle everything — number porting, hardware, installation, and staff training. Minimal disruption to your business throughout.
We don't disappear after go-live. Vantage provides ongoing support so you're never left stuck with a phone system that isn't working.
We port your existing phone numbers to the new system — customers call the same number, nothing changes from their end.
VoIP typically costs less than PSTN/ISDN. Most businesses we migrate see a reduction in their monthly telecoms bill from day one.
Get a free, no-obligation audit today. We'll tell you exactly what you need to do — and how little it costs to get it sorted.
Book a Free AuditOr call us directly: 01924 562 269 · support@vantagecomms.co.uk