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The Beginning of the End for ISDN

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The Beginning of the End for ISDN

With BT proposing to shut down ISDN 2 lines from 2020 and to have all ISDN 2 and ISDN 30 lines closed by 2025, we have to ask: where to next for business voice lines?


SIP has now established itself as the defacto replacement for ISDN. It offers on premise communications with capabilities far past that of its predecessor. Almost instant provisioning, numbering and all for much lower rental rates and installation cost, not to mention free calls.

Delivery and demand for cloud telephony systems has also been increasing significantly in recent years. Saul Branch our Operations Director believes this popularity will only continue to rise. He said ‘we are seeing a significant trend towards hosted telephony systems where in the past we would have installed on premise PBX – interestingly we are now deploying hosted into larger requirements on a regular basis, whereas this technology used to be popular with smaller organisations only’.

The advantages of having SIP as your telephone systems’ lines rather than ISDN are still abundant. They include:  flexible numbering, channel increases at the touch of a button, inexpensive inherent disaster recovery options and much more resilient build options.

These are just some of the benefits of SIP over ISDN but there are many more. Really we could question what’s taken BT so long to shut these other lines down considering the huge benefits of SIP and cloud hosted telephony against ISDN?

Whilst SIP line functionality over ISDN is great, the options offered by cloud hosted telephony really pull all of Voice Over IP’s features into one place.


Hosted gives companies the power to become self-sufficient with monitoring their own communications through an online portal, as well as having portal based administration and live configuration should any issues arise. Cloud Hosted systems have no need for on site equipment installation (apart from handsets) so installation charges are negligible compared to more traditional PBX deployments. In addition, hosted systems are pay per seat per month commercial models with flexible system scaling for any changes in employee numbers.

Final Thoughts

While many businesses across the UK now have SIP or hosted and have no issue with the ISDN switch off, those that don’t will need to pick the short term option of SIP or the longer term solution of hosted communications. The choice is there, however it must be made quickly as the process of ISDN switch off begins in just over two years.

Perhaps in eight years’ time the majority of businesses will be using cloud based telephony. Maybe the reign of hosted will be in full flow and only continue to grow as younger generations grow up. Society is already seeing changes in popularity for different forms of media so why not other forms of communication as well, be that private, public or business. The rise of hosted telephony is certainly in motion and will only increase as communications become ever more digital. After all who wouldn’t want to communicate efficiently?

Unsure of what to do before the switch off? Call us on 01993 777120 or Email

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