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The ISDN Switch Off (what it means and what to do)

The ISDN Switch Off December 2025

In 2015, BT announced their plans to switch off the ISDN and PTSN networks by December 2025. Leaving many people wondering why they’re switching it off, what it means to their business and what they need to do about it. 

This article is intended to give you all the information you need to make an informed decision, so that by the time you finish reading this page, you’ll know the answers to all of the above questions and know your exact next steps to take. 

So let’s first address the reason for the ISDN switch off. 

Why Are BT Switching Off ISDN?

ISDN has done a great job since it was introduced in 1986, but as the demands on the network have increased significantly over recent years – a faster, more flexible solution is desperately needed. 

And so instead of spending their time trying to constantly maintain a network that is outdated, BT have decided to upgrade to IP technology. 

What This May Mean To Your Business

If your business is currently relying on an ISDN line, you will need to switch over to an alternative before December 2025. 

The good news is, both ISDN replacements can provide a much better service than your existing line, with far greater flexibility (and possibly at a lower cost). 

This will depend on the company you use to make the switch, and the level of service they provide, but as an example, if you were to switch to our cloud based phone system, you would get:

  • Better call quality than your current ISDN line
  • The ability to make and receive calls from anywhere in the world with an internet connection
  • Call recordings for training and monitoring purposes
  • Smart queuing and call routing
  • Skype for Business and CRM integration options
  • The ability to keep your existing phone numbers
  • and more 
Cloud PBX phone

What Will Replace ISDN?

The two options you have are: Hosted VoIP (voice over Internet Protocol) and SIP (Session Initiation Protocol). 

The best ISDN replacement for you will depend on your particular business’s requirements, as well as your current set up. 

Both solutions are very similar, and so we’re going to now explain the key determining factors when choosing between the two. 

When To Switch From ISDN To SIP

For businesses who already have a legacy PBX in place that they’re happy with, and an IT department that’s doing a good job managing it – a SIP trunk solution may be best for you. 

SIP integrates your current PBX with VoIP, allowing you to continue using your phones as you have been. 

This may also be advantageous if you’re concerned about the time you’ll need to spend training staff to use new hardware. 

When To Switch From ISDN To Hosted VoIP

For businesses who either do not have (or wish to continue using) a legacy PBX, a hosted VoIP solution is more suited for you. 

Whether you’re looking to free up your IT department’s time, reduce ongoing costs, easily integrate with CRMs or make it easier and quicker to make changes to your phone system – it’s likely to be far cheaper to switch to a cloud hosted VoIP. 

Moving To An Internet Dependant Future

Whether you decide to use SIP or a cloud hosted VoIP, you’ll need to have an internet connection that can handle the increased demands you’ll be placing on it. 

This is because both hosted VoIP and SIP rely on a fast, stable internet connection to function. 

If you’d like to find out if your current connection is ready for 2025, you can click here and a member of our team will check for free.

What You Need To Do Next

Most businesses have already made the switch over from ISDN, so they have nothing to worry about when December 2025 comes. 

If you’re not one of those, you definitely want to act now so that you do not have to make a rushed decision closer to the time and risk any potential downtime. 

If you’d like any free help or advice, feel free to get in touch with our team by clicking on the button below to request a call back today. 

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APC Solutions

APC Solutions

APC Solutions offer a wide range of connectivity solutions across the commercial sector in the UK. If you’d like to learn more about how they can help you make the switch from ISDN, click on the link below to request a call back from an expert today

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