Smooth Transition to the ISDN 2025 Switch-off: A Guide for Businesses

12th September 2023
Reading time < 3 minutes

The ISDN switch-off is a major event that will impact organisations of all sizes in the UK. In this blog post, we discuss the importance of this transition and provide tips on how you can prepare. 

  • 2018: BT makes formal notification to stop selling and withdraw ISDN. 
  • 2020: Five-year reminder that ISDN and PSTN will be withdrawn. 
  • 2023: Stop sell of new ISDN and PSTN services begins. 
  • 2025: 
    • April: Forced migration to SIP/cloud telephony begins. 
    • December: ISDN and PSTN services are withdrawn. 

We have just entered the stop sell phase of the ISDN switch-off. What does this entail?

It means that organisations can no longer purchase new ISDN lines or renew existing contracts. This is a significant milestone in the ISDN switch-off process, and it is important that organisations start planning their migration to a new technology as soon as possible.

Key Points During the Stop Sell Phase: 

  • No new orders for any analogue line/ISDN lines or standard broadband. 
  • No changes to any existing services. 
  • Organisations should start planning their migration to a new technology  

What does the ISDN switch off mean for my organisation?

  • ISDN and PSTN are being phased out. BT has announced that it will stop providing these services in 2025. This means that organisations that are still using ISDN or PSTN will need to switch to a new technology before that time.  
  • Change can be a good thing... These are legacy technologies that is not as reliable as modern alternatives, such as VoIP,. which is a more robust and scalable technology that can provide better call quality and reliability.  
  • Because they are an aging technology, the costs are increasing, while the cost of VoIP is decreasing. This means that organisations can save money by making the switch.
  • The ISDN switch-off will impact organisations of all sizes as it also affects Analogue Phonelines, which, in turn, can the affect the broadband that you use also. No organisation is too small to be affected by this major event.  

How can you prepare your business for the ISDN switch-off? 

  • Start planning as early as possible to minimise disruption. The ISDN switch-off is a major event that will take time to plan for. Organisations should start planning as early as possible to minimise any disruption. 
  • Evaluate your current telecommunications needs. Before you can choose a new technology, you need to evaluate your current telecommunications needs. This includes understanding your call volume, features, and budget. 
  • Choose a new technology. There are several different technologies to switch to, such as VoIP, SIP trunking, and hosted PBX. The best technology will depend on your organisation’s specific needs.  
  • Migrate your data. If you are switching to a new technology, you will need to migrate your data. This includes your phone numbers, contacts, and voicemail recordings. 
  • Test your new system. Once you have migrated your data, you need to test your new system to make sure it is working properly. 

How can DB Comms support with the ISDN 2025 Switch-off? 

DB Comms is a leading provider of business telecommunications solutions for businesses. We can help you prepare for the ISDN switch-off by: 

  • Providing expert advice on the ISDN switch-off 
  • Evaluating your telecommunications needs 
  • Choosing the right technology for your organisation
  • Migrating your data 
  • Testing your new system 

We understand that running your organisation is your top priority, so let us take care of the ISDN switch-off for you. We'll handle everything from planning to implementation, so you can focus on what you do best. 

Time is key 

The ISDN switch-off is a big change, but it doesn't have to be a headache. DB Comms can help you make the transition to VoIP with ease. We'll take care of everything from planning to implementation, so you can focus on what you do best.

Don't leave your organisation's future to chance. Contact DB Comms today for a personalised consultation and find out how we can help you prepare for the ISDN switch-off. Your smooth transition begins here.


Jargon busting 

ISDN - Integrated Services Digital Network 

PSTN - Public Switched Telephone Network 

VoIP - Voice over Internet Protocol