Last Updated on October 28, 2025
The Big Switch Off marks the end of traditional copper landlines in the UK. BT is shutting down the Public Switched Telephone Network (PSTN) and ISDN lines to move all voice services to digital technology.
This change affects every business using landline phones, alarms, card machines, lifts, and fax systems that rely on copper lines. If your business still depends on traditional phone infrastructure, now is the time to act.
Switching to a digital landline service like Air Landline helps you keep your business number, stay compliant, and continue working without interruptions.
The goal of this guide is to explain what is changing, why it is happening, and how you can move to a modern system smoothly.
What is the BT Switch Off?
The BT Switch Off is the nationwide shutdown of copper-based phone lines. This includes PSTN and ISDN services, which have been in place for decades.
Instead of physical phone lines, all calls will run through broadband using Voice over Internet Protocol (VoIP). This shift means businesses must replace their landline systems and move to digital phone services.
The change is permanent. Landlines will no longer work unless they are connected to a digital provider.
Air Landline offers a quick and reliable way to move your number to a virtual landline that runs over the internet.
Why is BT moving from physical landlines to VoIP?
Copper landline infrastructure is outdated, expensive to maintain, and limited in features. VoIP is cheaper, more flexible, and easier to scale.
It supports features such as call recording, mobile call access, voicemail to email, and virtual numbers. Most countries across Europe have already moved to digital phone systems.
BT is following the same path to modernise UK communications. For businesses, this shift means better reliability and lower running costs.
Air Landline uses VoIP technology to turn your mobile or broadband connection into a landline number without needing hardware or engineer visits.
When is the final date for the switch?
BT has already started the stop-sell phase, which means no new analogue or ISDN lines can be purchased.
BT has confirmed that all PSTN and ISDN services will be switched off by December 2025.
From September 2023, new PSTN or ISDN lines can no longer be purchased. By 2025, every business and home must be using a digital phone service. If you wait too long, your existing landline may stop working overnight.
Services like card machines, door entry systems, care alarms, and fax services that depend on copper lines will also stop functioning. Moving early gives you time to test new systems and avoid service disruption.
What does the Big Switch Off mean for your business?
Many businesses still rely on an analogue line to run phones, alarms, or card machines, which will no longer function after the switch. If your business uses a landline to take calls, process payments, or run security systems, you will be affected.
When copper lines are disconnected, traditional phones will stop working. Business owners must move their landline numbers to a digital provider before the deadline.
Failing to switch means missed calls, lost customers, and extra costs for emergency replacements. Digital landlines, like Air Landline, work on existing broadband or mobile networks.
You do not need new wiring or expensive hardware. You simply redirect your landline number to your mobile or computer. This ensures you keep your number and stay reachable.
Does this affect residential as well as businesses?
Yes, the switch impacts both residential and business users. Homes using traditional landlines must move to a digital voice service.
This is often called BT Digital Voice for residential users. Businesses, however, need a more flexible system that supports call forwarding, multiple users, call menus, and voicemail management.
Air Landline is designed for business owners who want an easy way to transfer their number while still using their mobile or existing devices.
Residential customers usually switch through their broadband provider, but business owners have more control with a virtual phone service.
PSTN & ISDN switch off
PSTN (Public Switched Telephone Network), a traditional phone network and ISDN (Integrated Services Digital Network) are the two main systems being retired. PSTN is the classic voice-only telephone system.
ISDN was introduced later to support voice and data, like fax and video conferencing. Both depend on copper wiring. They cannot support the demands of modern businesses that rely on internet-based tools.
The big BT Switch Off, as explained by BT, states that after 2025, all voice services will be delivered through VoIP and internet protocol systems.
This also affects security alarms, EPOS systems, and lift emergency phones relying on analogue connections.
What do I need to do next to ensure my business is not left behind?
Digital telephony solutions, like Air Landline, make the transition smoother without extra hardware. Start by checking how your business currently uses its landline.
List every system that relies on PSTN or ISDN, such as phones, payment terminals, alarms, and intercoms. Contact your current provider and ask how they plan to support the transition.
If they do not offer a digital solution that fits your needs, move your number to a digital provider.
Air Landline allows you to keep your existing landline number and route it to your mobile or computer. No engineers, no contracts, and no downtime. Sign up online and start receiving calls instantly.
Can I just have a landline without internet?
No. After the switch, landlines will no longer work without internet or mobile data. To keep your number working, you’ll need either business internet or a stable mobile data connection.
All calls will travel through broadband or mobile networks. If you do not have internet, you will need mobile access to use digital voice services.
Some providers may offer basic digital phone lines bundled with broadband. However, this still requires an internet connection.
With Air Landline, you do not need physical broadband in your office. You can route your landline number directly to your mobile. This makes it easier for remote teams, small shops, and home offices to stay connected.
Transfer your landline over to Air Landline
Air Landline lets you keep your existing business number and transfer it online through landline porting. Your number is moved from the copper network to a digital platform.
Once transferred, calls to your landline will ring on your mobile phone or any device you choose.
You will not lose service during the switch. This gives you a modern phone system without installation, wires, or long contracts.
Virtual Landline Numbers: Get started with Air Landline today
Air Landline offers virtual landline numbers that work across devices. This is ideal for business owners who want a landline number without being tied to one location.
You can answer calls on your mobile, tablet, or desktop app. You can add team members, manage voicemails, and track call activity in one dashboard. No physical phone line is required.
You simply choose your area code, set up your account, and start taking calls.
Step 1
Pick a local or national number from Air Landline’s list of 660+ UK area codes.
You can select a number that matches your business location or one that appeals to a broader audience
Step 2
In the next step, you’ll need to enter your personal details, such as your first and last name, and your address.
Step 3
Start receiving calls on your mobile or computer. You can add features like voicemail, call routing, and business hours.
Start Your 7-day Trial and begin using your number instantly.
FAQ
The better option is to transfer your number to a digital service.
Summary – The Big BT Switch off
The Big Switch off is ending traditional landlines in the UK. By December 2025, all PSTN and ISDN services will stop working.
Businesses must move to digital phone systems like VoIP to stay connected.
Air Landline makes the switch simple by allowing you to transfer your landline number and receive calls on your mobile or computer.