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End of the line for ISDN – Prepare your business for the future of Telephony

The end is near for telephony as we know it, with BT getting ready to retire its ISDN services by 2025. Don’t get left behind, start exploring alternatives today.

ISDN – What is it?

ISDN (Integrated services digital network) is a set of protocols which allow for the transmission of voice, video, and data across the vast and varying infrastructure of the Public Switched Telephone Network (PSTN). ISDN was revolutionary when it was introduced; often referred to as the ‘original high-speed broadband’ it allowed voice and data to travel across the same copper lines and introduced new, previously unavailable features to telephony when it came into effect in the late eighties.

Why are ISDN services being withdrawn?

The infrastructure on which ISDN services operate – the PSTN – is reaching the end of its useful life. Some of the ageing components of the system are proving difficult to replace as parts are no longer being manufactured and many of the individuals responsible for creating the system have retired or are nearing retirement. Additionally, with the decline of landline use in recent years the system is bringing in less revenue just as maintenance costs are increasing, making its continued operation economically unviable.

What is the PSTN being replaced with?

Over the last decade or so, Telecoms operators have been busy constructing new IP-based networks. You may not have noticed much upheaval however as not all parts of the PSTN have been replaced. In other cases, providers have installed a new IP network alongside the old network, retaining the PSTN for calls while the new IP network is used for broadband.

How should I prepare for the long-expected ISDN switch off?

You can still purchase ISDN phone lines but with the demise of the PSTN round the corner investing in traditional telephony isn’t a particularly wise move.

The transition to full IP-based networks will require all customers to adopt a VoIP service. VoIP (Voice over internet protocol) is basically the new ISDN – a group of technologies that relay voice and video across the internet.

VoIP telephony can be implemented in several ways:

  • SIP Trunks. These are essentially ‘virtual phone lines’ that can be purchased and plugged into any IP compatible PBX server.
  • Hybrid Phone System. A system that combines a mix of technologies – IP, ISDN, analogue and digital.
  • Cloud-hosted phone system. A phone system without the associated infrastructure investment. You essentially pay to use a virtual PBX that you can access from anywhere through any internet connection.
  • IP phone system. Like a traditional phone system only with IP enabled handsets connected via ethernet cables to a local area or wide area network


We’re Netplatforms.

We’re Net Platforms and we have years of experience in supporting small-medium businesses across London and Essex with such technology challenges. We’ll get to know your business and create the most appropriate solution to meet your technical requirements while being commercially sensible in cost. Why not get in touch with our team today and explore how you can prepare your business for the future of telephony with VoIP technologies. 0207 993 9035 or


Book a no-obligation discovery call with a member of our team today by calling 0207 993 9035 or