What does the ‘digital switchover’ mean? Why is the switchover happening? We answer these questions and more in this article, to help you understand what steps you need to take prior to the 2025 ISDN switch off.

What does ‘the digital switchover’ mean?

By the end of 2025, analogue telephone services accessed by PSTN will be switched off as the UK’s telecoms network is upgraded from copper to digital connectivity. Services such as ISDN – used to transmit voice, video and other data – will also stop working.

VoIP is the leading technology that will replace calls made via PSTN and ISDN. This means voice calls will be made in the same way that broadband works, with data being transferred over the internet. The UK isn’t the first to do this – Belgium, France, Germany, The Netherlands, Sweden and Switzerland have all already made the switch.

The switchover isn’t just affecting landlines – anything that relies on the traditional PSTN network (such as alarm, fire, or security systems) will stop working too. This means the change will affect nearly anything that plugs into existing analogue telephone wall sockets.

There is no way to avoid the changes – the switchover is across the entire country – so businesses must act to ensure they’re not left behind.

Why is the digital switchover happening?

The switchover is happening so Openreach can move to a system where all voice calls are internet-based and delivered through a fibre network, to coincide with the upgrade to fibre technology across the UK.

Key definitions

All IP: refers to using Internet Protocol to connect voice, broadband and other services, instead of a telephone line

Cloud/hosted: ‘cloud telephones’ or ‘hosted telephones’ are operated remotely via the internet, removing the need for on-site PBX systems

ISDN: Integrated Services Digital Network. This uses the PSTN to operate, and has been in use since the 1980s.

PSTN: Public Switched Telephone Network. The traditional copper-wire network has been used for communication since 1876.

Stop sell: Is the date from which Openreach stopped selling certain products. Customers who already have the products can continue using them until they are withdrawn, but no new orders can be placed.

VoIP: Voice over Internet Protocol. Instead of traditional phone lines, which connect two phones with a dedicated, wired connection, IP translates the spoken voice into digital ‘packets’, which are then sent over an internet connection.

Key dates

September 2023 – Openreach stopped accepting orders for ISDN and PSTN, from new or existing customers. This is what is known as a ‘stop sell’. This included ADSL, FTTC, and WRL lines.

December 2025 – the PSTN network will be switched off, meaning technology that relies on it will no longer work.

What do businesses need to do?

This will all depend on the technology you are currently using, and the technology that is available to your premises. Contact your ISP or telecoms partner, who will be able to guide you in making the switch.

We’ve answered some common questions that businesses ask us about the digital switchover here.