The countdown has begun for the BT ISDN switch-off in the UK, scheduled to complete nationwide by 2025. Are you ready to futureproof your business and ensure uninterrupted communication? Let’s dive into what’s happening and how you can make a smooth transition to digital telephony.  

Understanding the ISDN switch-off 

BT is set to retire the UK’s PSTN and ISDN networks, marking the end of an era for analogue phone services. This move will impact countless businesses, especially those caught off guard by BT’s decision to phase out this outdated technology. Traditional ISDN phone lines come with high maintenance costs and numerous limitations, making the transition to modern solutions imperative.  

To highlight the significance of this change, on September 5, 2023, BT implemented a “STOP SELL” directive, preventing the ordering of new traditional ISDN and PSTN services and alterations to existing services. By 2025, and progressing across the country exchange by exchange, BT will have completed a nationwide switch-off of the existing ISDN and PSTN services.  

How can Cerberus Networks assist your business?  

We understand the challenges businesses face during this digital switchover. We offer a comprehensive range of connectivity and telecom solutions to ensure your ISDN to digital transition is smooth and hassle-free.  

1. Digital Voice Services  

Our SIP phone services offer flexibility, low cost and bundled UK calls, enabling your team to work seamlessly from any location.  

2. Telephone Systems  

Out VoIP, cloud-hosted phone systems enhance efficiency while delivering cutting-edge features that boost productivity.  

3. Business Mobile  

Choose from our range of business mobile plans across various networks, tariffs, and handsets.  

4. Business Internet  

Experience lightning-fast, cost-effective Ethernet and full-fibre broadband packages that provide your business with ultra-reliable internet connectivity, designed to support voice-over-IP services.  

The Urgency of the ISDN switch-off  

It’s a concern that only a fraction of UK businesses are aware of the impending ISDN switch-off, with only a third of smaller businesses and less than 10% of larger enterprises proactively adapting to IP-based systems.  

What and when is being switched off?  

Regarding the BT ISDN switch-off, two simultaneous initiatives are in motion: the Full Fibre Priority Exchange Programme and the retirement of analogue services dependent on copper lines, namely PSTN and ISDN. Both projects are slated for completion by 2025, with the Fibre Exchange Programme aiming to achieve 85% broadband coverage by the end of that year.  

The implementation of these initiatives is already well underway, and it’s crucial for businesses to prepare for the inevitable change.  

Benefits of replacing ISDN and PSTN switch-off  

Reliable and Faster Broadband  

Full-fibre broadband is up to 5 times more reliable, and 25 times faster than traditional copper line-based broadband used before the BT PSTN switch-off.  

Better Collaboration  

A unified communications infrastructure using platforms like Microsoft Teams and CRMs such as Salesforce streamlines business processes and fosters collaboration and innovation.  

Improved Efficiency  

Digital voice services and cloud-based phone systems are more scalable and efficient, all while remaining budget-friendly.  

More Sustainable  

Full-fibre connectivity is more energy-efficient and requires fewer resources than PSTN lines, making for a more sustainable communication infrastructure.  

Why Choose Cerberus Networks?  

Seamless Transition  

We make your digital changeover process hassle-free, ensuring minimal disruptions to your day-to-day operations.  


With a team of skilled experts, we provide robust technical support to all our clients. By partnering with Cerberus Networks, you can stay ahead of the UK’s ISDN switch-off and remain at the forefront of the evolving communications landscape.  

Don’t wait until it’s too late. Prepare your business for the BT ISDN switch-off and ensure a smooth transition to the future of telecommunications with Cerberus Networks. Contact us today for a consultation to secure your business’s communication needs.  

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