VoIP Guides | 2025 ISDN Switch Off

What The 2025 ISDN Switch Off Means For Your Business

The 5 year phase out plan of the ISDN switch off is well on its way across the UK. But what exactly is the ISDN switch off and what does it mean for your company? The switch off will have even more effects than you’d think, including on your phone and video call systems.

Our guide takes you through why the ISDN will affect you and how you can make the switch to avoid any interruptions to your business.

Office worker picking up a phone handset before the ISDN switch off

Why is ISDN being switched off?

ISDN has been a reliable solution for a long time, but it can no longer compete to maintain modern business communications. Broadband internet connection speeds nowadays are a lot faster and reliable. In short, ISDN is outdated. There are better solutions available, so ISDN networks will be completely retired in 2025.

When will the ISDN lines switch off?

All of the ISDN lines will be switched off in 2025. No new orders of ISDN have been sold by BT since 2020 as they have been slowly phasing out their ISDN lines.  

OpenReach plan to keep selling ISDN lines until 2023, but business owners would be wise to look for alternatives to future-proof their daily operations.  

What will the switch off mean for your business?

If your business is using physical ISDN lines to make phone and video calls, you need to switch. After the ISDN switch off, you won’t be able to make those calls anymore. You will need to switch to digital to keep your business running.  

What many businesses don’t know is that ISDN doesn’t just affect your phone calls. Everything connected to your ISDN lines will need to be upgraded to digital. This can include your business:

  • Office alarms 
  • EPOS machines 
  • CCTV
  • Fax machines 

iCompario tip:

Switching from ISDN to an alternative takes time. If you have a multi-storey office or many premises, you’re looking at a longer time frame. The sooner you switch, the fewer delays you will face in the future. The number one alternative to ISDN is VoIP 

Should we all be using VoIP?

ISDN can’t compete with the faster speeds of the internet. This is why ISDN providers have stopped updating their ISDN lines and almost stopped selling altogether.  

But the ISDN switch off doesn’t mean your business will be left dead in the water. VoIP is the lifeboat your business will need when the lines are switched off and we recommend jumping on it before the 2025 rush demand grows.  

What is VoIP?

Call at the click of a button! VoIP waves farewell to the traditional phone lines and clunky systems of the past. With a VoIP system, you’ll be using the internet to make video and phone calls all over the world.  

iCompario tip:

VoIP can be mixed with your CRM (Customer Relationship Management) system for better customer service. This way, you can see call history, past interactions, and call recordings all in one place. 

Man using VoIP to make a call from company laptop at work

The benefits of VoIP

Switching from ISDN to a hosted phone system shouldn’t be daunting. This switch doesn’t just upgrade your phone system. This is an upgrade to your overall telecom’s operations. From cutting costs to improving your management time, VoIP has many benefits to offer all businesses.  


VoIP is cheaper than ISDN systems. The cost is lower because it requires less equipment, so your provider doesn’t have to pile the maintenance costs onto you. Since all you need is internet, you don’t have to pay to upgrade or install new phone lines. Plus, you can find offers for all kind of businesses. Get a VoIP phone system for small business to stay on budget or an advanced IP phone system to cover your big organisation needs.  


As long as you have internet, anything goes. If your team works on a hybrid or remote model, VoIP is an ideal solution. Your team no longer needs to be in the office to make calls. You can be soaking up the sun on a beach holiday and still make those important calls. If you want to recruit remote-based talent, VoIP is the future-proof solution you’ll need.  

Any device

VoIP systems can be used on your phone, laptop, PC, mobile handset and tablet. As long as you have an internet connection, you can make business calls with any device you prefer.  

Hassle-free management

Unlike older ISDN systems, VoIP puts all your management onto an online system in the cloud. Whether you choose to manage everything from an app or tool, it takes the hardware management off your hands.  

Improved reliability

If you use an ISDN system right now, you’ve probably noticed longer call out times for repairs and maintenance. That’s because providers are phasing out ISDN. 

But VoIP runs on the internet, right? Yes. You might think that if your broadband goes down, you wouldn’t be able to make phone calls. But VoIP providers have a variety of solutions, so your operations aren’t interrupted. One of the most popular solutions is to install a backup connection, so you always have a Plan B.  

How to switch to VoIP

  1. Check your internet connection. You’ll need a high speed for the best service.  
  2. Check that your phone system can use VoIP. If not, you’ll have to switch to one that does.  
  3. Recommended: choose a cloud-based online telephony system. This supports remote working and gives you an online management tool.  
  4. Compare VoIP providers to get the best system for your business.  

Switching over from ISDN to VoIP doesn’t have to be a hassle. With the right provider and system, your business can unlock new benefits, faster speeds, and even reduce costs by jumping on the VoIP bandwagon to prepare for the ISDN switch off.  

There are many types of VoIP systems to suit every business. We compare reliable UK VoIP providers, so you can find the most efficient telecoms solution for your business. 

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