• Paul Welham

ISDN and the 2025 Switch Off


The Public Switch Telephone Network (PSTN), which supports a number of business services in the UK, including ISDN, is due to reach it’s end of life in December 2025.

ISDN stands for Integrated Service Digital Network. It is a line that runs through copper wiring allowing both voice and data to be delivered, although more commonly used for business as a voice channel – each channel providing 1 concurrent call.

Back in 2015, BT Openreach announced that they would stop accepting new ISDN orders in 2020 with a view to deactivating the network in 2025. This means that any copper cabling used for voice calls (ISDN, PSTN, Multi-line) would stop working and only be used for data traffic such as Fibre broadband – FTTC (Fibre to the cabinet) where the line runs from the green cabinet to your business premises.

Traditional copper cabling for ISDN at least, has been used as part of the UK's telephone network for over thirty years but is now becoming end of life, as costly to repair and newer 21st century digital technology, is a far better alternative. These new digital technologies such as ultrafast full fibre optic cabling is now the priority for Openreach and can now be planned and rolled out across the country, as part of an updated telecoms infrastructure.

Although the ISDN switch-off will be phased, it is a good idea, If you haven’t already, to now start thinking about future-proofing your business telecoms. A good place to start is with your current telephone system – what type do you use and how old is it?

IP telephony, or VoIP (Voice over Internet Protocol), telecoms systems have been around for a while and provide significant benefits for businesses over traditional telephony, so you may find it an advantage to change over sooner.


VoIP offers lower costs, greater flexibility and can help you provide the best possible service to your customers with added features such as team management and call routing.

Many IP telephony systems are also hosted or cloud based, so there’s no need for lots of on-site equipment. It is also ideal for flexible or remote working because the system can be accessed from anywhere, simply using the broadband connection. Be sure to check that your current internet connection is good enough to host VoIP or if you're upgrading, it needs to be secure, reliable and fast.

Did you know? Small businesses that switched to VoIP save 40% on local calls and 90% on international calls (TechCo)

If you need further advice about preparing for the ISDN switch off and future proofing your business telecoms, with the advantages of VoIP, call us on 01603 550044 or email info@purenexus.co.uk

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