Is your business ready for the ISDN switch off?

You may not have heard about it – but a massive change is coming in – with a big impact for small businesses.

What is happening and why?

From December 2025, BT Openreach is closing down all ISDN lines – which will basically mean an end to landlines in the UK and the lines most commonly used to make phone calls across the world.

It’s happening as part of a move to shut down the Public Switched Telephone Network (PSTN) – which ISDN is a part of – because it’s become outdated and been overtaken by newer technologies, such as fibre broadband.

Once the shutdown is complete, a fully digital network will take its place – but it’s a move that will impact all businesses currently using landlines and other PSTN products.

What exactly does this mean?

Called ‘The Great Switch Off’, this is the biggest communications change in a generation.

In short, it means that any PSTN-based products that your business uses today will need to change.

PSTN not only supports traditional landlines, but also voice services such as ISDN2/30. The bulk of widely available broadband services, such as fibre-to-the-cabinet (FTTC) or standard broadband (ADSL), also rely on the PSTN.

Voice will become completely digital and delivered over the internet using Voice-over Internet Protocol (VoIP) technology.

Broadband services will begin transitioning to Full Fibre (FTTP) and single order broadband (SOGEA). These don’t rely on landlines and are fully future-proofed, offering fast download speeds of up to 900Mbps.

Are there any benefits for businesses?

Yes, lots!

VoIP only requires an internet connection to work. This means you’ll be able to say goodbye to costly, old-fashioned analogue phone lines in your offices.

Because of this, businesses will benefit from better call quality and faster networks. This will in turn improve innovation, increase productivity, and keep teams tight via hyperconnectivity.

The move towards more flexible and inclusive hybrid experiences will therefore be bolstered and future-ready operations and intelligent workspaces will be better enabled.

There are several great partners out there who can support with your migration. Be sure to research your options and look for a company who can help make this process a smooth and successful one – readying your business for the future.


For more support, guidance and free 1-2-1 business advice, you can also speak to one of our V-Hub Digital Advisers