The BT ISDN Switch Off – what it means for your business.


The impact of the BT ISDN Switch Off

In 2015, BT announced that their Integrated Services Digital Network (ISDN) and  Public Switched Telephone Network (PSTN) lines will be switched off by 2025.


In the 1980’2, PSTN was considered the advanced digital platform of its time, allowing calls to be made over copper and fibre telephone lines using analogue signalling.


However now, as technology has evolved, it has increasingly become outdated telephony and harder to maintain.


In the last decade, broadband services have increased in reliability and quality and the PSTN has evolved to support this change to an almost completely digital network. As a consequence, traditional fixed line telephony using analogue services for calls have become obsolete and unable to support an increasingly digital world demanding quality and speed for voice calls or data.


Now, it’s all in the cloud. Cloud-based services eliminate the need for phone lines and provide the communications that supports your hybrid working.

What is the timeline for the BT ISDN Switch Off?

BT Announce the ISDN Switch Off
BT Announced that it would be eliminating all ISDN and PSTN lines by 2025. This marked the beginning of the biggest change to happen to telecommunications in over 30 years.
August 2022
500 locations to no longer have ISDN
By August 2022, over 500 locations in the UK will no longer have the capability to obtain ISDN or PSTN.
August 2022
"Stop Sell" Complete by BT
No access to new ISDN/PSTN lines, UK-wide with total switch off Salisbury and Mildenhall. Inevitable decline in support to fix issues.
BT ISDN Switch Off Complete
The BT ISDN Switch Off will be complete and if you have not made the switch by then, you will be in danger of your telecommunications being unsupported with parts almost definitely no longer available.

So, how do I plan for the BT Switch Off?

There is still time to plan, however, it is not advisable to leave all your planning until 2025.


Some locations are already unable to access PSTN or ISDN, such as Mildenhall and Salisbury. BT will continue its plan to stop selling ISDN lines particularly in areas that have achieved high coverage with gigabit capable networks.


Whilst there will still be trained engineers to service ISDN lines, parts will continue to decline, meaning that it will become increasingly difficult to repair and coupled with an expected decline in network quality you may wish to start planning the switch now.


Consider these next steps:

  1. Check whether you are one of the locations to have already stopped
  2. If you are not, then confirm the date that BT will be stopping in your area
  3. Check your current telephone system contract renewal date
  4. Begin to plan what you will switch to post the BT ISDN Switch Off

What are your options post the BT ISDN Switch Off?

Everyone will need to upgrade to an internet based VoIP system.


Voice over Internet Protocol (VoIP), is the capability of making phones calls over the internet. This is not new technology but has become a highly cost-effective and reliable way to handle calls for the future.


There are a few ways that you can access VoIP.


You can implement SIP Trunks, which is technology that allows you to make calls over a data connection connected to a compatible IP Phone system. This is considered a great half way house between an on-premises solution and a fully hosted platform.


However, to achieve the greatest flexibility for your business, implementing a fully hosted cloud communications platform. 


The Benefits of moving to Cloud Communications

Old man on a blue background

Supports cohesive communication

Implementing Cloud Communications eliminates issues surrounding integration, deployment and multi-vendor contracts as it provides a consolidated solution and the latest technology.


Why are BT Switching off ISDN?

ISDN and PSTN are the backbone of the UK’s telephone network. However, with dramatic changes in technology, particularly in recent years with the emergence of smartphones, apps, cloud applications, IOT, the copper cables are no longer capable of keeping up with these advances. 

What will replace ISDN?

IP will deliver the technology that is needed to ensure telecommunications remains flexible, reliable and scalable. 

Are ISDN lines being phased out?

In short yes they are, and BT are updating information all the time. Essentially 500 locations are being placed on a stop by August 2022 with a completion date for this by 2023. Whilst existing BT lines will still be functional, service will be in decline with a lack of parts available for any repairs necessary, making it increasingly difficult to service. 

Are BT getting rid of phone lines?

All landline networks will become obsolete and replaced by the IP digital network. You need to plan now as the areas on a stop sell increase, resulting in a decrease in service to existing lines. 

Read our White Paper on the ISDN Switch-Off

Download our white paper below to find out more on the impact on your business.

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