BT's ISDN Shutdown in 2025. Here is what you need to know.

VoIP and BT’s ISDN Shutdown



In 2025, BT will conduct major changes to its services, as a result permanently shutting down ISDN and traditional PSTN services. This means that some existing phone systems will not work past this date.

What does this mean for small-medium businesses? What alternatives are there?

According to efax over 2 million UK businesses will be affected by the switch off, primarily small businesses. Businesses with a heavy use of fax machines or landlines telephones will feel the biggest impact.

Why is BT shutting down their analogue signalling phone systems?

ISDN and traditional PSTN networks are known as “traditional telephony”. This system allows calls to be made over copper telephone lines using analogue signalling. As of 2023, BT will no longer offer businesses the ability to acquire ISDN and PSTN. Following this, the total BT’s ISDN shutdown will occur in 2025.

The end the use of analogue phone lines will subsequently move communications technology into an entirely digital space. SIP trunking, which is essentially a virtual telephone line, is now set to overtake ISDN.

What is the reason for the shutdown?

According to BT, the current copper wire system relies on technology devised centuries ago. The costs of maintaining it are incredibly high and rising, in spite of the many adaptations and improvements to this service. An overall review has concluded that in general, ISDN and PSTN services are not optimised for modern business. Especially as there are plenty of other methods of data transmission available that are cheaper, faster, more reliable and scalable.

As a result, small businesses are now turning to their IT support providers for a new telephony solution.
Hosted VoIP in particular is considered to be one of the most cost effective and flexible telephone communication solutions.

Using our hosted voice servers, all you need to do is to have an internet connection, connect to a VoIP phone and away you go!

Dont be affected by the BT’s ISDN Shutdown! Contact us to get the ball rolling.


Download the following PDF to find out more:

  • What is VoIP and what are the differences to a landline?
  • What are the benefits of VoIP?
  • How to make the switch to VoIP.
  • Basic terminology that you may find useful.