The Retirement of ISDN… Reality or Hype?


The Retirement of ISDN – Introduction

During a BT Group Q3 2014/15 results announcement, Gavin Patterson, BT Group CEO, stated that BT intended to migrate their voice network to Voice over Internet Protocol (VoIP).

Whilst no formal dates were announced, it was intimated that BT will stop selling PSTN and ISDN services by 2020 and subsequently shut down these services completely by 2025.

As an ICT consultancy, we at 4C Strategies are very interested in this. Is it reality, or is it just hype?

What’s Happening?

With little evidence of any progress to date, 4C Strategies contacted Gavin Patterson’s office for an updated position statement.

They did reconfirm their intentions, but indicated the regulator and suppliers still need to approve any plans moving forward before making, and committing to, any further announcements.

What about the other key industry players? We approached the major vendors, both direct providers and resellers of BT Services, for their views on the announcements.   None were prepared to commit to specific dates.  Whilst they have a number of their own plans, they continue to await any formal notification from BT itself and it is unlikely that anyone will precede BT.

Will BT really flick the switch? Is 2025 too optimistic? We’ll wait and see.  But the target date of 2025 is for all services to be switched off – so, on the basis of the statements made thus far, retirements could start any-time after 2020.

What Should We Be Doing?

Whilst 2025 may seem a long way off, 2020 is just two years away. Many large organisations still have ISDN services as a key part of their carrier services strategy.  For some, ISDN is retained for resilience purposes, but others remain wholly dependent upon ISDN services.  No carrier has confirmed what notice periods they will provide, nor how they will retire ISDN. Will it be nationwide, geographic or more random, based upon exchange technologies?

From past experience, some customers may only be given 12 months’ notice and some localised retirements may be well in advance of the nationwide dates – whenever they may occur.  Is that long enough to review your carrier services provision and implement all necessary changes?

We know the answer is SIP, but the means are many and varied.  Now is the time to start exploring the options and benefits of VoIP and SIP technologies, before the retirement of ISDN forces your organisation’s hand. There are, of course, many questions and dependencies.  For example:

  • Is VoIP right for your business?
  • How and when can you make the move?
  • Is your Internet connection strong enough to deliver VoIP?
  • Does your phone system support VoIP?

How Can an ICT Consultancy Help?

4C Strategies is an independent ICT consultancy with a 19-year track record in major telephony projects.

We’ve helped numerous NHS Trusts, Universities, Colleges, Councils and private sector companies to update or replace their telephony infrastructure.

Our services include:

  • Position statement with respect to current telephony;
  • Business needs assessment;
  • Market assessment;
  • Strategy development;
  • Procurement support;
  • Deployment and transformation;
  • Realisation of benefits.

How Do I Find Out More from a Qualified ICT Consultant?

For more information on 4C Strategies, and on how our ICT consultancy services have helped our clients, please visit our website at

To arrange a no obligation introductory visit from one of our Principal ICT Consultants, please contact us by emailing or, alternatively, call us 01858 438938.