How To Cope With The Death Of The Dial Tone

Dr Lucy Green, Managing Director of Larato, shares her expert advice on how to evolve beyond the PSTN and ISDN switch off.

Britain’s telephone network is set to undergo its biggest change since Queen Victoria purchased one of the first services in 1878. Since this auspicious order was placed, the nation’s voice calls have been carried over copper wires. In 2025 Openreach will switch these copper networks off, simultaneously withdrawing PSTN, ISDN and Carrier Pre-Selection (CPS) services and moving services onto the data networks that deliver broadband. As the dial tone is consigned to history, millions of lines must transition from PSTN/ISDN to IP. Other devices like security alarms that rely on these technologies are affected too.

Openreach has been rigid with its timescales. Don’t expect delays. This is happening. And it starts now with the withdrawal of five-year contracts for ISDN and PSTN services.

Although millions of UK lines still use PSTN and ISDN, they are outdated technologies whose replacement is well overdue. Switzerland, Germany and Greece have already phased them out. Australia, New Zealand and France will all “switch off” before the UK.

What changes are happening?

Openreach’s plan is well covered. Daisy’s “The Big 2025 Switch Off” provides a rounded and impartial description of what’s coming. If you intend to do your own research, be careful; some guides are biased towards particular suppliers. Despite its focus on consumers, Ofcom’s “The future of fixed telephone services” is an informative read.


If your business uses PSTN, ISDN or CPS, then you have two choices:

  • Wait and see what happens
  • Plan your transition now and implement the changes at the best time for you

If you do nothing, you will expose your business to avoidable risk and cost. Services will be transitioned, by choice or by mandate. From 2023, you won’t be able to buy PSTN, ISDN or CPS at all and as switch-off approaches, your options will narrow. I would anticipate increased costs if there is a last-minute rush.

Conversely, if you plan your transition now, you will find out what you need to do and the best time to act. It could be that the best time for you to make the change is close to the switch off date. But without a plan, you won’t know.

Top tips to help your business flourish from the change

  1. Make sure you have good, consistent broadband connectivity. Rural areas suffer from lack of coverage. In busy cities, high levels of demand often impact broadband speed. Although voice does not require a lot of bandwidth, it does need consistent, resilient connectivity that is managed to a high service level. Without these, you will experience poor call quality and dropped calls. In my experience, many suppliers lack the technical competencies to configure and manage voice call delivery over broadband. Choose carefully.
  2. Take advantage of new regulations and grants. In 2018, Ofcom introduced a Universal Service Obligation, entitling eligible businesses to a “decent” broadband connection by 2020. There are also some other government schemes, so it is always worth being aware or getting involved with local authorities as to what is potentially available.
  3. If your business has a highly-customised, or even custom-built, telephony system, it’s important to find out how to connect it to the new networks that will be delivering voice services. If you want to keep your existing systems, you need to move from ISDN to SIP. This could be nice and straightforward. Or it could be difficult and require specialist skills. Despite its reputation for simplicity, sometimes SIP is complex. Don’t wait until the last minute to find out your transition is going to be tough.
  4. Consider upgrading and streamlining your existing systems to newer solutions such as unified communications or Microsoft Teams. These are the technologies of the future. They provide opportunities to improve productivity, support remote working and offer more flexible ways of communicating with your customers, including “Alexa-like” voice-activated features.

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