Thousands of businesses across the UK still haven’t migrated away from PSTN and ISDN. If you’re one of them, this is for you.
The UK’s copper-based PSTN and ISDN networks will be retired in January 2027. Most businesses have already made the switch, but if you haven’t, it’s not too late. You still have time to do this properly if you act now.
Every month you wait, your options shrink, costs rise, and the risk of disruption grows. The good news? You can still get ahead, but you need to start today.
The switch-off is a fixed industry deadline. From January 2027, these services will be switched off completely. Providers have already started withdrawing support, and lead times for migration are getting longer as demand spikes.
It's going to get expensive...
Waiting will cost you more than you think. Carrier partners have confirmed three major price hikes in 2026: April (+20%), July (+40%), and October (+40%). By year-end, costs will have effectively doubled, and those increases will be passed straight to customers. If you’re still relying on copper services, you’ll end up paying more for something that’s on the verge of being switched off.
If you miss the deadline, your PSTN and ISDN lines will stop working. No partial service. No fallback. It's not just the office phone systems that stop working, it can be surprising how many systems rely on the legacy lines - fire alarms, lifts, refuge points, emergency services, fax machines, lone worker systems and panic buttons... if it 'dials out' it's likely to get affected.
And beyond disruption, the consequences get serious:
- Compliance breaches: Fire safety and emergency systems often have legal obligations.
- Insurance invalidation: If alarms fail, your cover could be void.
- Lost revenue: Payment failures mean missed sales and angry customers.
- Reputational damage: Customers and partners notice when you are offline.
It's not just phones!
The copper switch-off affects more than voice lines. It includes:
- PSTN, ISDN2, ISDN30 (traditional voice services)
- DSL and ADSL2+ broadband (data services)
If you rely on these for alarms, lifts, fax machines, or remote diagnostic systems, you are exposed. Many businesses assume they have already switched until they audit and find hidden dependencies.
A chance to modernise
Migrating is not just about avoiding disruption. It is an opportunity to modernise:
- Full fibre reliability: Higher speeds, fewer faults, and better uptime
- Rich features: Unified communications, video conferencing, and advanced call handling
- Scalability: Easier to add sites or users as your business grows
- Future-proofing: Align with how businesses now work, including cloud, hybrid, and remote
Acting now means you can:
- Upgrade access: Move to FTTP/Ethernet or best-available SoGEA/Cellular
- Modernise voice: Replace PSTN Single Line Voice and PBX with UC offerings
- Build resilience: Dual-path connectivity, LTE/5G backup
- Enhance security: Firewalls, SD-WAN, managed LAN/Wi-Fi
Common misconceptions
- “We have moved to VoIP, so we are fine.” Maybe not. Many businesses still have analogue lines for alarms or lifts.
- “We will sort it next year.” Migration is not instant. It involves planning, hardware changes, and sometimes network upgrades.
- “The provider will handle it.” They will switch the network off. The responsibility to migrate sits with you.
Who’s Exposed?
Any organisation still using:
- Analogue lines for alarms or lifts
- Legacy fax or payment systems
- Sites without IP-based connectivity
Questions to Ask Before You Start
- Which services still rely on copper today (lines, alarms, payment, lift)?
- Do these services have a planned journey to cloud or IP?
- What broadband do you use today?
- Any compliance or uptime targets (SLA, emergency calling)?
- Do systems require resilience (secondary circuit or 4G/5G failover)?
Typical Migration Outcomes
- Single PSTN Voice → FTTP/SOGEA + UC
- Door Entry Systems → Webex Horizon + ATA hardware
- Fax Lines → UC with ATA hardware
- Lift Lines → IoT/Cellular
- Remote Diagnostics → IoT/Cellular
What To Do Next
Do not wait for the deadline to dictate your move. Secure your migration slot now and speak to an Intercity specialist today. We will help you:
- Schedule the switch without disruption
The PSTN and ISDN switch-off is coming. It is not optional. But it is manageable if you start now. Audit, plan, and partner with experts who have done this before. That is how you stay in control.