ISDN Switch Off

All PSTN and ISDN phone networks will be switched to a fully digital network by 2025. Every phone call you take, make or transfer will now be routed over the Internet. Make the transition to digital seamless with Lily's help. Find out how we can prepare you for the BT ISDN Switch Off below.

What Is the BT ISDN Switch Off?

BT Openreach will phase out all ISDN and PSTN telecommunication networks in 2025. Integrated Services Digital Networks (ISDN) are phone lines that transfer digital data over the Public Switched Telephone Network (PSTN). The country is moving towards a digital IP fibre network, leaving these obsolete landlines behind. 

Organisations are now adopting telephony that runs over IP and additional connectivity to support communication. Your existing fixed landline will no longer be supported soon, so you can avoid costly downtime with a cloud phone system.  


When Will ISDN be Switched Off?

BT will be switching off all ISDN and PSTN by December 2025. Many businesses and homes that rely on ISDN must move to a new service compatible with the IP network.

In September 2023, the nation entered into its final Stop Sell. Copper-related solutions can no longer be ordered. This marked a significant milestone, pushing organisations to prepare for the end of ISDN. The switch to full-fibre is closer than you think.

How Does It Affect Businesses?

The future is digital, but the change that follows with it can be costly and disruptive for your business. 

The ISDN and PSTN Switch Off will impact all existing infrastructure that relies on this technology, such as phone lines, CCTV, intercom systems and alarms. These systems will no longer work, leaving your business vulnerable to disrupted services until you change to a hosted phone system and fibre broadband.  

Don’t put yourself at risk. Prepare your business for the ISDN Switch Off today!


What Do I Need to Do?

Future-proof your business and join the IP and cloud-based technology switchover movement. The best alternative for any business on an ISDN network is Voice over Internet Protocol (VoIP) phone systems. Powered by the IP, VoIP allows voice and video data to be seamlessly transmitted over the internet so that you can benefit from a cost-effective, flexible and mobile communication infrastructure.

At Lily, we’ll help you through this transition and ensure your business remains unaffected.

Prepare for the ISDN Switch Off 2025

As part of our Lily Cloud solution, we offer a VoIP telephone system that accelerates your digital transformation journey by leaving old and obsolete technology behind.

Save costs, boost productivity and improve customer experience with a VoIP system. At Lily, we can help make the ISDN Switch Off effortless with minimal disruption to your operations.

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VoIP Phone System Benefits

Saves you money

VoIP technology delivers high-quality calls, saving you between 30-60% off your monthly line rental when you switch from ISDN or analogue lines. You’ll also reduce hardware costs and ongoing expenses, like usage fees, taxes and long-distance calls.

Grows with you

Our cloud-based phone system requires minimal hardware compared to legacy systems, making it a perfect choice for businesses looking to expand their operations. VoIP systems are easily scalable and meet your needs as you grow.

Creates a mobile workforce

VoIP makes working from home, the office or even the road possible. Make and receive calls from anywhere with an internet connection. Our hosted phone system enables remote working and supports business continuity during potential office disruption.

Modernises your call system

Our fully hosted VoIP phone system gives you access to all the ISDN system features you know and love, like call handling, voicemail and caller ID. Now, you can video call and live message and improve customer experience with call recording, analytics and CRM integrations.

Business Broadband Solutions

Changing to a hosted phone system means you’ll rely on your broadband more than ever. Superfast internet speeds are crucial to providing excellent service all year round. By pairing FTTP or SoGEA broadband with VoIP, your business will be future-proofed and secure from disruption.


Single Order Generic Ethernet Access (SoGEA) enables broadband connection without a landline. SoGEA is a practical solution for your VoIP phone system, delivering great coverage and superfast internet speeds of 80Mbps. You’ll only need a single line for broadband and IP, saving money while future-proofing your business

Discover SoGEA Broadband


Fibre to the Premise (FTTP) delivers ultra-fast internet straight from fibre optic cables. When paired with our hosted VoIP telephone system, you can do more and help more customers. FTTP offers higher speeds up to 1Gbps, making it ideal for bandwidth-intensive solutions like video conferencing. FTTP is a popular choice with many businesses, as it can quickly scale as you grow.

Discover FTTP Broadband

Helpful Resources

ISDN Switch Off FAQs

The ISDN Switch Off is BT Openreach’s phase-out of ISDN and PSTN services. Business and residential properties will move to internet-based technologies, including VoIP phone systems and Fibre to the Premises (FTTP) broadband.

The world is becoming increasingly digital, making the ISDN and PSTN infrastructure obsolete and difficult to maintain. BT Openreach is transitioning the UK to a fully digital network to improve efficiency, flexibility and costs.

Stop Sell refers to an area that can no longer sell or buy Wholesale Line Rental (WLR) products, including analogue or ISDN phone lines. Businesses in a Stop Sell area can continue using WLR products until they’re withdrawn in 2025.

Public Switched Telephone Network (PSTN) is a traditional analogue communication network that uses copper lines to support phone calls. PSTN has been the backbone of the UK’s telecommunications since 1876.

The Integrated Services Digital Network (ISDN) is a digital communication system that transfers speech and data over the PSTN. Since the 1980s, ISDN has improved call quality, data transfer and communication. Newer technologies, such as IP, have overtaken it.

SoGEA stands for Single Order Generic Ethernet Access. SoGEA delivers a landline and broadband connection through a single line, which previously required two lines. It is an ideal replacement for traditional phone lines and FTTC (Fibre to the Cabinet) broadband.

SoGEA offers the same internet speeds and coverage as FTTC and helps businesses future-proof their communications ahead of the switch off. 

Fibre to the Premises (FTTP) is a fibre optic broadband that provides high-speed internet to a person’s premises using fibre IP cables. It can reach up to 1Gbps, making it ideal for businesses increasingly relying on bandwidth for cloud solutions. 

FTTP offers reliable connectivity with minimal signal loss, and it can easily be scaled to meet the growing needs of a business.

We offer a free, no obligation quote, tailor made by our friendly team of advisors. Contact us today on 0343 507 1111.

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