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If your business still uses traditional phone lines, there’s a significant change coming that you need to plan for. The UK’s PSTN (Public Switched Telephone Network), the copper wire telephone infrastructure that has powered businesses for over a century, is being permanently switched off. The deadline is January 2027, and all businesses relying on PSTN lines will need to have moved to an alternative before then.
Here’s everything you need to know.
What is PSTN?
PSTN stands for Public Switched Telephone Network. It’s the traditional telephone network, the system of copper wires, exchanges, and physical infrastructure that connects telephone handsets and allows voice calls to be made. In the UK, this infrastructure is managed by Openreach.
A PSTN phone line is what most people would simply call a “phone line”, the kind that has been in offices and homes for decades. ISDN (Integrated Services Digital Network) is an evolution of PSTN that allows digital data and voice to be transmitted over the same line, commonly used by businesses for higher-quality calls and multiple lines.
Why is the PSTN Being Switched Off?
The PSTN switch-off is happening for several reasons:
- The infrastructure is ageing and increasingly expensive to maintain
- Usage has declined dramatically as businesses and consumers have moved to broadband and mobile
- The equipment and components required to support copper networks are becoming harder to source
- Modern IP-based (internet-based) communications are more capable, flexible, and cost-effective
What Services Are Affected?
The switch-off affects any service that runs over a traditional copper phone line, including:
- Standard analogue phone lines used for voice calls
- ISDN lines (including ISDN2 and ISDN30)
- Broadband delivered over copper using ADSL or FTTC (in some cases)
- Fax machines connected to PSTN lines
- Alarm systems, door entry systems, and lifts connected to PSTN lines
- Payment terminals and EPOS systems using dial-up connections
The last category often catches businesses by surprise. If you have security alarms, fire alarms, access control systems, or card payment terminals connected to a PSTN line, these will also need to be migrated or replaced.
PSTN to VoIP: The Natural Replacement
For most businesses, the natural replacement for a PSTN phone line is VoIP (Voice over Internet Protocol). VoIP delivers voice calls over your broadband or leased line connection, offering:
- Lower cost per call, especially for multi-site or international calls
- Greater flexibility: staff can use the same number from any device, anywhere
- Advanced features including auto-attendants, call recording, and voicemail-to-email
- Easy scalability as your business grows or changes
Migrating from PSTN to VoIP doesn’t have to be disruptive. With careful planning and the right provider, you can port your existing numbers, maintain continuity of service, and often reduce your monthly telecoms costs in the process.
Don’t Leave It Too Late
With the deadline approaching, demand for VoIP migrations is increasing. Providers and engineers are becoming busier, and last-minute migrations carry a higher risk of disruption. Acting early gives you more choice, more time, and a smoother transition.
How SilverCloud Can Help
SilverCloud specialises in helping UK businesses navigate the PSTN switch-off. We’ll audit your current telephony setup, recommend the right VoIP solution, and manage the migration from start to finish — ensuring no disruption to your business operations.