BT is switching off the entire UK public telephone network by January 2027. Every business using analogue phone lines, ISDN2e or ISDN30 must migrate to VoIP. Don't leave it until the last minute — migrate now for free with Telexico.
PSTN (Public Switched Telephone Network) is the traditional copper wire phone network that has connected UK businesses and homes since the 1800s. BT Openreach has announced it will switch off the entire PSTN infrastructure by January 2027 and replace it with an all-IP (internet-based) network.
This affects every business in the UK using any of the following: analogue phone lines (PSTN), ISDN2e, ISDN30, FTTC broadband (which requires a phone line), business broadband delivered over copper.
BT has already implemented a Stop Sell on new PSTN/ISDN products in many exchanges. You cannot get new ISDN lines in most areas. Existing lines will be switched off area by area from now until January 2027.
Any phone line delivered over a copper wire (not fibre) will stop working when PSTN switches off.
All ISDN services are being withdrawn entirely. These cannot be kept — you must migrate to SIP trunks or VoIP.
Fax requires an analogue phone line. All PSTN-connected fax machines will stop working. Cloud fax alternatives exist.
Older PDQ terminals connected via PSTN will fail. Your payment provider must migrate your terminal.
FTTC broadband requires a phone line for the copper segment. When PSTN switches off, FTTC goes with it.
Digi-communicators using PSTN connectivity in alarm systems will fail. These must be upgraded to IP or 4G.
PSTN (Public Switched Telephone Network) is the traditional copper wire phone network that has connected UK businesses and homes since the 1800s. BT Openreach has announced it will switch off the entire PSTN infrastructure by January 2027 and replace it with an all-IP (internet-based) network.
This affects every business in the UK using any of the following: analogue phone lines (PSTN), ISDN2e, ISDN30, FTTC broadband (which requires a phone line), business broadband delivered over copper.
BT has already implemented a Stop Sell on new PSTN/ISDN products in many exchanges. You cannot get new ISDN lines in most areas. Existing lines will be switched off area by area from now until January 2027.
Check if any of the following apply to your business — if even one does, you need to act before January 2027:
We audit your existing phone lines, numbers and call routing.
We design your new VoIP system to match or improve on your current setup.
Your existing numbers are ported to the new system. No disruption.
Your team is trained. Old lines cancelled. You're PSTN-ready.
BT has set January 2027 as the full switch-off deadline. However, Stop Sell — where no new PSTN/ISDN lines can be ordered — is already in effect in many UK exchanges. Your existing lines will be switched off on a rolling basis by area before the final deadline.
No — we port your existing phone numbers to the new VoIP system. Your customers dial exactly the same numbers. You keep your local Birmingham 0121 number, freephone numbers, DDIs — all of them.
We can typically have your new system live within 5–7 working days. Number porting takes a further 7–14 working days. We run both systems in parallel during the transition so there is no gap in service.
Alarm systems using PSTN diallers will stop working. Your alarm installer needs to upgrade the communicator to IP or 4G. Telexico can advise and install IP/4G communicators as part of your overall PSTN migration.
With Telexico, VoIP migration is free — we don't charge for porting your numbers or reconfiguring your system. In almost all cases, your monthly costs also reduce significantly compared to ISDN line rental.
Click your area for local pricing and case studies.
"Switched our entire office phone system and broadband. The team handled everything, zero downtime. Saving over £200 a month compared to our old BT contract."
"Had failover installed after losing internet for a whole day. Assure X kicks in within seconds. Our team didn't even notice when the main line dropped last week."
"Our dental practice needed reliable phones and fast broadband. Telexico sorted everything in one visit. The AI receptionist handles after-hours calls brilliantly."
Free, no-obligation quote. UK-based support. Same-day response.