Reminder – The Great BT ISDN Switch Off: BT Phasing Out ISDN By 2025

The Great BT ISDN Switch Off: BT Phasing Out ISDN By 2025

BT intends to switch off the PSTN and ISDN networks for good, starting with a cease in supply in 2020 and moving to a full migration by 2025. The BT ISDN switch off could affect many businesses in the near future, especially those unaware of BT phasing out ISDN and looking to invest in or upgrade their current business telephone system.

Why Are BT Phasing Out ISDN and PSTN?

The short answer is that they are old fashioned legacy technologies with associated maintenance costs and drawbacks. PSTN is the traditional telephone line network which carries analogue voice data over copper lines. This technology (although vastly improved upon over the years) is basically the same in principle and design as the early telephone networks of the late 1800’s.

ISDN came about in the 1980’s, allowing both voice and data services to be delivered simultaneously. For the technology and services at the time, it served its purpose very well and continued to do so for many years. But just as we have moved on from the limited functionality of brick sized mobile phones, so too do we need to move with the times in other areas. The BT ISDN switch off was just a matter of time but thankfully they have given us plenty of it to adjust.

How To Prepare For The BT ISDN Switch Off

Although the BT ISDN end of life of 2025 has not been set in stone, businesses will be unable to buy systems that use ISDN and PSTN after 2020. If you currently have a traditional ISDN/PSTN based system, now is a good point to look into the alternative. Although there is plenty of time until 2025 rolls around, it’s best to plan ahead and you may actually find you want to migrate sooner rather than later after finding out all of the benefits the replacement ‘IP’ based systems have to offer.

If you’re in the position where you haven’t got a business telephone system yet, you are in the perfect place to start afresh with an IP based telephone solution. This way you can negate any needless expenditure on technology and hardware with a limited shelf life and future proof your small/growing business. BT phasing out ISDN will have no negative effect on you in this case and you may in fact gain a competitive advantage over your competition.

IP Technology – Life After The Great BT ISDN Switch Off

IP (Internet Protocol) telephony has been around for a while and many businesses have already benefitted from the technology. Eventually all phone lines will be superseded by IP technology, which is vastly superior to what we have used in the past. Here’s a quick overview of the main business benefits for using hosted VoIP:

It’s very affordable/cost effective

There’s no need for masses of on site equipment, you only pay for as many users as you need and calls are made through internet lines.

Easy setup/maintenance

Because there is so little on site equipment, setting up and maintaining the system is a much simpler job than with a traditional telephone system.


The flexible nature of the technology allows you to easily add and remove users as you need. Physical location doesn’t matter, anywhere you’ve got an internet connection, you can have a number.

As you can see, the great BT ISDN switch off is as much an opportunity as it is a problem, it just depends on your perspective. One thing’s for sure though, BT ISDN end of life is around the corner and hopefully, now you’re a bit more prepared for it.

If you have any questions or if we can help you any further, please click on our live chat or give us a call or call 01524 39212 today to discuss your options!