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The ISDN Switch Off 

Get ahead of the telecoms switch off

The telephone network as we know it has started to change. The ‘2025 Switch Off’ is a big milestone within the telecommunications industry, and although it may seem far away, you need to start planning your move now to see how this could impact you and your business. 


Remember, this switch off isn’t just about phones. All analogue lines will be switched off, so you need to review everything connected to them, which could include alarms, payment terminals, fax and franking machines


What is PSTN & ISDN?

The PSTN (Public Switched Technology Network) is the traditional, copper wire-based telephone network which has remained largely unchanged since the early days of public telephone networks. 


ISDN (Integrated Services Digital Network) is a digital platform that came into use in the 1980s to deliver not only voice, but video and other data too. 

What is the PSTN & ISDN Switch Off?

We’re all familiar with the copper wire telephone network: in use since 1876, it’s kept business communications’ going for years. But that’s all about to change.

In 2025, the Public Switched Telephone Network (PSTN) is being switched off by BT Openreach, which means everyone, including businesses, currently using PSTN-based services will need to move to another service before then.

The alternative? Voice over Internet Protocol (VoIP), a solution that transmits voice calls and data using an internet connection.

This is a major step towards the United Kingdom’s mass IP-network migration, with VoIP core networks set to replace all the legacy PSTN services in just a few years’ time.

Embrace the future of telephony by replacing your landline with VoIP before the Public Switch Telephone Network (PSTN) is switched off in 2025.

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What is replacing PSTN & ISDN?

From 2025, all consumers and businesses will make phone calls over broadband using VoIP systems. Voice over Internet Protocol (VoIP) allows voice communications over IP networks such as the internet. VoIP does not require a circuit-switched network. Instead, data is transmitted over a digital network. BT plans to switch to a system where all voice calls are internet-based and delivered via a fibre network, correlating with the upgrade of fibre networks across the UK, to support the shift to VoIP telephony.

VoIP calls can be made using a wide range of devices, including desktop computers, mobile phones, landlines and pretty much any other internet-ready device. 

What is VoIP?

VoIP stands for Voice Over Internet Protocol and is often referred to as IP (internet) telephony or cloud-based telephony. In plain terms, VoIP systems make phone calls using the internet, rather than the traditional telephone exchange or landline network.

VoIP allows calls to be made on any device that has a reliable internet connection, including smartphones and laptops. A VoIP phone system is much more flexible, as they can be provisioned remotely, meaning you can add additional lines to the system easily. Call costs via VoIP are much cheaper when compared to traditional phone systems and usually come with innovative features.

Click here to download our super helpful guide

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Find out more about how to make the switch from ISDN, your options on switching and more information on how this switch has many more benefits than simply not being on legacy tech.

Benefits of VoIP

VoIP is a much better alternative to traditional landlines, and it will be the industry standard for years to come. This technology offers many opportunities and benefits for your business:

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Lower Costs

VoIP solutions are software-based, which means you don’t need any infrastructure, upfront costs, or additional hardware.


Additional Features

VoIP deskphones come with a wider range of phone features as standard, including video calling, Presence status, voicemails to email and easy-to-use call settings when needing to manage calls.



As they are cloud-based, VoIP phone systems are easier to scale, meaning you can add additional handsets as your business grows. You’re only ever paying for what you need.


Increased Call Quality

As VoIP phone systems use your internet connection, the call quality on phone calls is much higher than systems still using an older network. The reliability of this connection is also much better.



VoIP solutions can be accessed from a variety of devices, which means you won’t be tied to a desk phone anymore and you’ll be able to take your calls wherever you are.


Future Proof 

You’ll be protected against the ISDN switch off while helping make your business more efficient and saving money.

What is the 'stop-sell" that is happening
right now? 

The ‘stop sell’ process is a preparatory stage before the 'Switch Off' where Openreach stops taking new orders for these services as in a few years they are turning them off. The ‘stop sell’ is happening now from exchanges on a geographic basis.  Although it won’t affect your existing services like the 'Switch Off' itself, this earlier milestone is significant as it means that you can’t add to or amend your existing services in their current analogue form from September 2023.

Find out more about how to make the switch from ISDN, your options on switching and more information on how this switch has many more benefits than simply not being on legacy tech.

Get ahead of the telecoms switch off and upgrade to a VoIP phone system today!

Find out how we can help upgrade your business to VoIP by completing your details here

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