We can advise on the best solution for your business.

ISDN Migration

As with all projects, the starting point is ‘why’. It is well publicised that Openreach will be ‘switching off’ ISDNs in 2025, with last orders in 2023 so there is no option; the other market development is that there are now products available that are better and more resilient than ISDNs.

All Cities Affect after December 2021

When the date was first published it was not made clear that the timetable would be a gradual switching off commencing in 2020 through to 2025, with every major city having a least one local exchange switched off by the end of 2021. This will affect a wide range of homes and businesses. As the schedule of exchanges being turned off is not published through to 2025 it is prudent to have the plan for transformation in place so the change can be planned.

The Cost of ISDN Circuits will Increase

ISDNs are largely supplied by Openreach (Cable & Wireless / Vodafone have already closed all but a few) where price controls operate so as the number of ISDNs reduce the wholesale rental of the circuit may remain unchanged, however the reduction of the number of circuits impacts the scale and the absorption of overheads required to manage ISDNs.

At network level there has been at least one key portal closed as the cost of maintaining security levels is not commercial; calling packages may be affected, and TPIs (Third Party Integrators), the interface between your telecoms provider and Openreach, costs will have to be covered by fewer and fewer circuits and so increasing the cost of individual circuits.

Also, ISDNs obviously require a PBX to manage call flows, one major manufacture has already announced their exit from the market and advised their distributors to ‘stop sell’. There are bound to be increased challenges for spares and support as the market contracts.

New Technology is Better

However, the main reason for changing is simply that the new technologies are better and usually commercially attractive.

There are many many features, the headlines include, working from anywhere with any internet connection, in addition to voice other communication channels are available including secure video calls and chat, and there are very detailed analytics which have not been available with ISDN without additionally equipment and costs.

The detailed analytics will help to provide a better service to your customers and manage your teams.

Call Quality is Better

The industry measures call quality on the MOS score (Mean Opinion Score), the scale is 1 to 5, ISDN calls are generally 3.6, calls can now be delivered regularly at 4.6+, and if there is a poor quality call the analytics cover the end-to-end detail and can be overlaid on Google maps.

The How

NSL’s dedicated team of telecom professionals will project manage the complete process and having worked with most technologies over the years deploying the new technologies is the easiest by a long way.

Please get in touch to start the exploration of what is possible.


  • Migrate before the switch off in 2025
  • We can advise which solution is best for your needs

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