Since 1876, the copper network has been the backbone of telephone communications throughout the UK. Over the years, this same network of copper cables has also served as the conduit for internet services, connecting people across the nation.

In December 2025, the ISDN (integrated service digital network) and PSTN (public switched telephone network) systems will permanently switch off. VoIP (Voice over Internet Protocol) technology will take over. This change is being referred to as the "copper switch off” and will allow for the widespread use of full-fibre broadband across the country.

The Copper (IDSN & PSTN) Switch Off Explained

The PSTN (public switched telephone network) supports traditional phone lines in the UK. It depends on copper cable networks that have been in use for nearly 150 years. The ISDN (integrated service digital network) utilises the same copper cable infrastructure in many instances but can also use fibre optic cables.

Both of these systems will turn off in December 2025. Voice over Internet Protocol (VoIP) technology will power all phone lines. Other systems utilising ISDN or PSTN lines, including traditional CCTV, alarms, and door-entry systems, will also transition to Internet Protocol.

Why is the Copper Switch Off Happening?

The PSTN network, which has been active for nearly 150 years, originally facilitated UK telephone communication. Its scope expanded with population growth and the digital revolution. ISDN was introduced in 1986 and enhanced the copper network, enabling additional services like FTTC (fibre to the cabinet) broadband. 

As consumer needs continually increase, the ageing network's reliability and capacity fall short. Transitioning from copper to VoIP offers households and businesses enhanced and more reliable broadband.

What is VoIP?

First used in the 1990s, VoIP (Voice over Internet Protocol) is a technology that enables you to make and take phone calls over the Internet. While standard PSTN and ISDN phone lines rely on the analogue system of copper cable networks, VoIP is digital—it simply requires an Internet connection and a VoIP-compatible phone.

The experience of making or receiving a VoIP call is very similar to a conventional call, so you won't notice the difference.

Switching to Digital

For most users, transitioning to VoIP involves connecting their VoIP-compatible phones directly to their routers instead of the traditional phone socket on the wall. Some may need a new phone or adapter, although many already possess VoIP capabilities. Also, modern routers often come equipped with VoIP connections. Before the switch-off occurs, it’s important to contact your broadband provider to ensure you have everything you need to transition without any issues.

How Will the Copper Switch-Off Affect Customers?

Changes are underway in certain areas with the copper switch-off. Nationally, traditional landline contracts ended in 2023, replaced by VoIP contracts ahead of the ISDN and PSTN switch-off by December 2025. Existing contracts extending to 2025 won't see price changes but may require phone line connection to routers.

For business owners concerned about their phone services, adopting VoIP technology proactively is smart. Almost half of UK businesses have transitioned to hosted telephony, integrating calls with their enterprise broadband. If your current contract relies on ISDN or PSTN lines, assess whether switching to VoIP is beneficial now or closer to 2025.

Upgrade Your Equipment Today

The transition from the traditional PSTN to digital VoIP calls is right around the corner and will be complete by December 2025. While the transition should be smooth for most customers, some may need to install new hardware and invest in new phones. It's advisable to upgrade your equipment now to ensure your household or business is ready.