PSTN, ISDN, the “big switch off” – they’ve all been spoken about across the telecommunications industry, but the facts can often get lost in the furore.

We’ve compiled this useful blog to help you understand what’s really happening and what you need to do to ensure your business is ready to adapt.

What is the PSTN and ISDN switch off?
The Public Switched Telephone Network (PSTN) has been in use in this country since 1876, so it’s understandably grown old and tired, and it’s becoming increasingly costly to maintain. Therefore, it needs replacing with new and modern technology, fit for the digital world we now live in.
As a result, the PSTN will reach end of life in December 2025 and will cease operation after then.
However, the PSTN supports several products from Openreach which are sold to businesses including Integrated Services Digital Network (ISDN) lines.
Depending on the size of business you operate, you could have either ISDN2 or ISDN30 lines. However, at the end of December 2025, these fixed lines and services will be switched off and services withdrawn.

What do I do if I’ve got an ISDN line?
1876 was the year Alexander Graham Bell made the first-ever telephone call. Fast forward 143 years and technology has changed dramatically and the world we work in today is unrecognisable.
Telephone services no longer have to rely on the ageing, and degrading, copper infrastructure from the past and instead services can be provided using Voice over Internet Protocol (VoIP).
However, for your new VoIP system to work, you’ll need a good quality internet connection so that your VoIP solution can run seamlessly.
If you’ve currently got an ISDN line, before December 2025 you’ll have to upgrade your telephony.

When will Openreach start withdrawing services?
We’re one of only a handful of providers that are actively involved in industry planning meetings regarding the PSTN switch-off so, rest assured, we’ll keep all of our customers in the loop.
Openreach started trialling the withdrawal of services in two exchanges in September, the first being in its Salisbury exchange, Wiltshire. There is a second site, the Mildenhall exchange, Bury St. Edmunds, which will also begin trial shortly.
Both sites are focused on a complete withdrawal of services by December 2022 with other exchanges not due to enter withdrawal until much closer to December 2025.

Will my broadband be impacted?
If you currently have a broadband service that is supported on a single line, your provider will be in touch to migrate this to an alternative single order broadband.
This means that your broadband will move to a single service with no line rental. If you’re using your line for voice you will be offered a Voice Over Internet Protocol (VOIP) alternative. If you already have an ultrafast fibre to the premise broadband product and do not use any voice services, you won’t see any changes as you’re already using new digital technology.

What happened in 2023?
From September 2023, Openreach will issue a full ‘Stop Sell’ of new supply and there will be no new line installation for Single PSTN Lines or ISDN. Consumer rights during this period will still be upheld so line transfers will be accepted, providing there is no change to the installation when the line moves from one provider to another.

What should I do now?
If you’re currently on an ISDN contract, you don’t need to do anything at the moment. But, be mindful that when your contract is up for renewal, you’ll probably need to switch to a hosted telephony solution.
However, if you’re looking to upgrade and futureproof your business now, you’ll need to ensure you’ve got a business-grade broadband solution and you’ll need to assess your hosted telephony options to make sure you’re getting the most out of your services.

What happens in 2025?
Your provider will strive to migrate all PSTN services to alternative solutions before the December 2025 deadline. However, if services still remain on the PSTN network, then they will be withdrawn in December 2025. If any businesses or consumers have failed to switch to alternative telephony, they will ultimately be left without service.