Everything You Need to Know About the BT 2025 Shut Off


The BT shut off will be taking place in 2025 and will be changing the way we make phone calls. The shut off will officially take place in 2025 but BT have confirmed a phased approach across the UK, with many regions affected by the shut off before this date.

Businesses must prepare for the shut off ahead of time to ensure a smooth transition whilst having minimal impact to the running of the business.

What is Being Shut Off?

BT are shutting off their ISDN and PSTN services. Instead, calls will be made over the internet, maintaining a high quality of voice and video calls, without being affected by the growing demand.

What is ISDN and PSTN Services?


Integrated Services Digital Network was introduced in 1986 and changed the way phone calls were made. With this telephone network system, data and voice is transmitted over a digital line.


Public Switched Telephone Network was launched back in the 1800s. Data is transmitted the traditional way, through a network of copper wires. For years, businesses have used PSTN to transmit phone calls and fax transmissions.

Why are They Being Shut Off?

ISDN and PSTN are outdated and are no longer effectively keep up with the demands of today’s communication requirements. ISDN phone lines were also costly and therefore BT decided back in 2015 they were no longer going to invest any money in updating it.

BT decided that shifting to a digital telephone network system was the best solution. Broadband speeds are also much faster than ISDN and cloud-based systems offer greater flexibility and scalability which is essential in today’s hybrid working world.

BT are now moving towards VoIP and SIP telephone systems.

What is VoIP and SIP?

Voice over Internet Protocol

Phone calls are made using the internet with VoIP telephone systems and calls are converted into packets of data which travel to the desired endpoint. Unlike traditional phone lines where calls can only be made from a handset, VoIP allows you to call out and receive calls from your desktop, laptop, smart phone or handset. Calls can be made from any location, as long as there is a good internet connection. Furthermore, your phone number will appear the same, no matter where in the world you are calling from.

What are the Benefits of VoIP?

There are a number of benefits of VoIP including reduced costs, accessible on multiple devices, enhanced voice/video quality and consistent phone number no matter where in the world you are located.

To find out more about the benefits, check out A Brief Guide to Hosted Voice Telephony (https://www.minervauk.com/a-brief-guide-to-hosted-voice-telephony-minerva/)

Session Initiation Protocol

SIP is the backbone to a hybrid PBX solution. SIP enables the call to happen, helps to facilitate the VoIP voice packets to transfer over the internet and also ends the connection.

What are the Benefits of SIP?

SIP is more cost effective than ISDN, voice and data is transferred from one connection, phone lines can be added and removed easily and quickly and the system can also help with fraud protection.

How Do I Switch?

We would recommend booking an initial telephony review with one of our telecoms specialists. We’ll have an in-depth discussion on your current telephony situation, your needs as a business and advise you on the best solution. Your current phone system may be compatible with IP, but if not, we can also explore new and suitable options.

As mentioned above, BT will be doing localised switch offs before 2025, so we highly advise looking into this as soon as possible. We will help you to ensure a smooth transition. Our partners provide 24/7 customer care, even after our work is done, should you need it.

To get started, just leave us an enquiry and a member of our team will get back to you