Do You Understand How BT’s Plans to Switch off ISDN and PSTN Circuits in 2025 Will Affect You?

On the 5th May 2017 Gavin Patterson the CEO of BT announced at an investor meeting that businesses have 8 years to look for an alternative solution to their telephony and internet needs as Openreach plans to switch of PSTN and ISDN services by then.  Fortunately, there are a range of affordable solutions available.

Let’s look at the current systems in place but note, from 2020, these systems will no longer be installed.



PSTN (Public Switched Telephone Network)  is the same phone line most people have at home, whereby analogue voice data flows over circuit-switched copper phone lines. While it may have evolved over the years, PSTN is a very, very old technology, operating on the same fundamental principles as the very first public phone networks of the late 19th Century. It is worth noting that PSTN does not just power voice, as asymmetric digital subscriber line (ADSL) and fibre-to-the-cabinet (FTTC) both operate on it. source


ISDN (Integrated Services Digital Network), by contrast, is a spritely young thing from the late 1980s. ISDN allows both voice and data services to be delivered over digital lines simultaneously. When it launched, ISDN was well-suited to businesses, as it could support early video-conferencing systems at the same time as an analogue phone line. For a time, it could also offer the fastest internet access available (128 kbps). Naturally, since ISDN is no longer the place to go for video-conferencing or a fast internet connection, its USP has quickly been eroded. source

So why is BT switching to IP?

BT introduced ISDN nationwide in 1986 and since then connectivity has advanced greatly. The recent investment and nationwide roll out of Superfast Fibre Internet and new Ethernet products provides a viable alternative. In fact, BT have not installed any new ISDN lines in central London since 2014 which goes to show that many businesses have already moved on. Switching over 3 million active ISDN users is no small task which is why have given businesses so much notice – although time is rapidly running out!

What are the alternatives?

The recent investment in the UK communications network has made the new fibre infrastructure widely available and affordable to small businesses. This means IP based solution such as VoIP and SIP are the top alternatives for businesses.

What is SIP?

SIP (Session Initiation protocol) Provides you with a phone line which is carried over your fibre internet connection removing the need for an ISDN phone line. SIP lines used to have reliability problems due to inadequate underlying broadband connections. These issues have now been fixed due to the recent connectivity improvements and Service Level Agreements now offered by providers.

What is VoIP?

We have written extensively about VoIP (Voice Over Internet Protocol) and what it is but in a nutshell, VoIP is a cloud based telephony solution which moves your whole phone system online so all your calls are sent over your internet connection. This digital cloud-based phone system offers a wide range of additional features such as call recording, receiving voicemails via email, call queuing and unified communications – being able to access the system on multiple devices such as a mobile, tablet and desktop.

Top 5 Benefits of SIP and VoIP

  1. Huge savings – Up to a 78% reduction in costs compared to ISDN due to cheaper calls and no more expensive line rental.
  2. Greater flexibility – Move anywhere in the World and simply plug back into the Broadband network with no need to change numbers. Your number can go with you wherever you are.
  3. Faster installation – No more waiting for an engineer to install physical lines means you can get connected faster.
  4. Higher resiliency – Multiple fibre lines can be installed providing an automatic backup and failover, so you’re always connected.
  5. Advanced features – Increased control, integration and analytics offers a huge range of new and advanced features including call recording which is essential for FCAs regulations MIiFiD II as of 6th January 2018.

So, what do you need to do to be ready for the switch off?

  1. Ensure your internet connection is good enough to deliver VoIP
  2. Check to see if your office phone system support VoIP

The most important thing is, if, you are planning to update your telephone system in the next 2 years, or you are opening a new business and will need a new system, think carefully about what you are going to install.  You don’t want a system that will soon no longer be supported and will need upgrading to one of the above systems.

If you want to know more about what your options are and how to future-proof your communications, then please give us a call on 03456885122 or drop us an email on

About Yvonne Roberts

Yvonne has spent the last 30 years in field sales, working up and down the UK. Deciding it was time retire the poor car before it died, she now is a prolific writer and teacher as well as writing and performing ceremonies as a civil celebrant. This means blogging comes off her pen as natural as breathing! Working with Connect-it gives her a platform to let her natural and alternative view on life to be expressed; as well as an understanding of the telecoms world.

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