ISDN AND PSTN switch off: Everything you need to know

HBT Communications

83 per cent of organisations still not aware of when their ISDN and PSTN services would be switched off.

The ‘BT ISDN and PSTN Switch Off’, will be a biggest shift in the way people make phone calls in the UK in recent history.

The official switch off will happen in 2025.

For business continuity, it is vital companies take action now to ensure they are prepared for the official switch off that will happen in 2025.

BT announced back in 2015 they will shut off their ISDN and PSTN services completely in 2025. Neither of these technologies can deliver the volume or quality of voice data needed in a world where digital technology is such a priority.

From 2025 all voice calls will be made over the internet.

According to the “Switch On to the Switch Off Survey 2021”, 83 per cent of organisations were still not aware of when their services would be switched off.

The Switch Off is fast approaching and your business cannot afford to delay on upgrading.

“The number of organisations we speak to daily who are still not aware of the switch off and the impact it will have on their business surprises me”, says Chris Whelan, sales manager at HBT Communications.

“My biggest fear is we don’t have a situation like they did in Germany, where everyone left it to the last minute, which meant there was not enough technical resource for everyone.

“Furthermore, changing now means business are saving money as calls to UK landline, non-geographic (0845,0844 etc) and even intentional destinations are all inclusive.

“Essentially the sooner this transition happens the more cost effective it is for your business”.


What will it affect?

The change affects both your telephone services and even some internet connection (Fibre To The Cabinet FTTC, ADSL2+). If you are unsure what services you have you can speak to HBT Communications who for 35 Years have been helping SME organisations with consultative and impartial advice.

HBT Communications can help your business through this change / transition of services.

Even better still, you will make savings by changing over, no more call charges to UK Landline, UK Mobile, Non-Geographic numbers and even free international calling. No more expensive maintenance/service contracts. 

The best way to avoid disruption during switchover in 2025 is by getting the process started, sooner rather than later. Then you won’t have to wait to experience a wide range of benefits, which include:

No more expensive hardware to worry about

With VoIP you have greater flexibility in how you communicate, as in addition to your desk phone you are also provided with a softphone and mobile client.

No more costly support contracts

With HBT’s VoIP solutions all support and maintenance in included free of charge.

Always on the latest version

Your system is always updated ensuring you are on the latest version ensuring you have access to new features released as part of the upgrade.


It’s not just during a global health crisis that VoIP supports your business. When your team is free to work from anywhere — back at the office, in a co-working centre, or even while on the move – you have maximum flexibility, and they can even use their own device.

How can we help?

HBT Communications have been in the communications sector since 1988 and cover all the UK. Our support team are based centrally from our Coventry Head Office and our consultants have over 60 years combined experience in delivering the best of breed solutions and ensuring that these are delivered in the most cost-effective way.

Contact Chris, your local representative via email at or call 02476 867400 today to discuss how we can help you.