Preparing for the 2025 ISDN/PSTN switch off – What Businesses Need to Know

All the way back in 2015 BT made the big announcement that it would be switching off what is known as the Public Switch Telephone Network (PSTN) alongside the Integrated Services Digital Network (ISDN).

Hardwired copper lines that connect many individual phone lines are becoming hard to maintain and both the PSTN and ISDN have reached their limit and are under pressure to meet the demands in volume and quality required in today’s fast past digital environment.

This switch off is set to happen in December 2025 and means that fixed telephone networks and landlines will be replaced with digital alternatives using an internet connection such as Voice over Internet Protocol (VoIP), Digital Voice or All IP telephony.

Fast forward and 2023 is already racing by and we are less than three years away from ‘traditional telephony’ being switched off – so what are some of the answers to businesses key concerns regarding the switch?

How much will the switch cost me and my business?

Whilst a huge change like this can seem a bit daunting for businesses there are a few important things to consider ahead of the switch over.

Many businesses will be concerned about cost and the switch may entail a set up fee to get things up and running however, the future cost savings, increased flexibility and scalability opportunities far outweigh this incremental fee in the long term. It’s essential to make this switch to improve communication infrastructure and stay competitive in the current market.

Will current lines be redundant?

Any devices or equipment that operate through the PSTN or ISDN infrastructure will be made redundant. That’s why it’s important to make the move towards new technologies that can greatly improve business processes and be the first step on your business’s digital transformation journey.

When should my business start planning the move?

As soon as possible. Not planning ahead for the PSTN/ISDN could lead to system outages, downtime, and reduced profits. It could also lead to your customers leaving for competitors who have already made the transition to digital communications.

Our expert team are working to give both our existing and any new clients as much information as possible in advance of the switch so that there is time to prepare. We’ll be creating a detailed migration plan so clients can be assured we have a solution in place and that they are supported throughout the transition.

For those that don’t have in inhouse IT team we can also conduct training sessions and provide support during the transition process, making it even easier to switch. Above all else this will help manage any risk with a proactive approach and ensure business continuity.

How can my business prepare?

The best way to prepare is to do an audit into your existing infrastructure. It is crucial to do this across your business and have a rethink about the products you currently use in advance. You may realise you no longer need wired desk phones or even work mobiles, particularly if you operate a hybrid or remote working model. You could even take advantage of applications that link to your existing software like Microsoft Teams.

You need to go through all your phones and hardware to check if they work through the PSTN or ISDN. Some systems may require upgrades or switching to IP mode to ensure they are compatible whilst others may need an adaptor or new power supply. In selected cases you may need to look for an IP equivalent.

If you are thinking of or are in the process of purchasing new products such as alarm systems and phone devices, make sure you check the compatibility of them beforehand, you don’t want your new systems becoming obsolete or creating more hassle in two years-time. This also means you need to check existing alarm systems, door entry systems fax machines or any other device that is connected to a phone line to ensure they still operate correctly before the switch off.

It is also worth noting that products that use services that make up the PSTN including WLR, ISDN2 and ISDN30 may also be affected. If you have products or broadband systems that use any of these, they too could cease to work following the switch off.

If you are unsure or are worried about your existing infrastructure, please don’t hesitate to get in touch with our team who are on hand to help advise you on your current technologies and can help make sure all your hardware is up to date and compatible, ensuring your business continues to operate with no down time when the switch happens.

What are my businesses options?

From Microsoft Teams and mobile networks to cloud telephony and SIP trunks there are a range of alternative telephony systems that can be integrated with your wider IT systems including (but not limited to):

  • Migrating from ISDN and PSTN to SIP Trunking: This solution can help businesses to transition effectively and make it easier to manage their voice and data traffic with the necessary bandwidth.
  • Cloud Telephony: Cloud telephony can be an excellent solution for businesses, as it only requires an internet connection to make and receive calls. It is easy to scale, and it provides enhanced features, such as call recording, call routing, and others.
  • VoIP: It is a cost-effective solution and provides efficient scalability for businesses that need to expand their communication infrastructure for the future.


All of these systems can easily be deployed and tailored to your business needs, and we can work with you to find the best solution for you and your organisation.

Do I need to review my current Internet Connectivity?

You will also need to ensure you have a have a high-quality internet connection in place – as most of your tools will now end up relying on them.

If you want to enjoy the newest innovations in IT services, including video conferencing and shared collaboration you need to check your current connectivity. It may be appropriate to look to upgrade to a dedicated network that specialises in providing superfast connectivity for businesses for more reliability and resilience.

Alongside this if you are a growing business looking to upgrade your IT infrastructure you can take advantage of our  free IT audit in preparation.

How secure are digital communications?

If you have concerns about the security of digital communications, you will want to make sure your internal network is secure as possible. Firewalls, encryption and two factor authentication will help ensure that calls are secure and if you are worried about the current systems you have in place it may be time to upgrade or look at stronger solutions.

What are the benefits of going digital?

As mentioned, moving to a fully digital form of telecommunications and infrastructure opens a range of new tools, features, and systems that businesses can use to improve internal and external communications and help existing systems and infrastructure work better alongside one another. These range from video conferencing and real time messaging to enhanced presence information and virtual PBX.

You’ll also have access to higher quality calls, the ability to have more than two people on any one call and easier ways share and collaborate. Contrary to popular belief it is also extremely reliable as digital services often run over multiple data centres so if one goes down traffic can easily be redirected keeping your systems online. VoIP also enables employees to work remotely as they are available anywhere in the world with an internet connection making them a viable option for multisite, hybrid and remote working businesses.

What’s more, VoIP services are often more cost effective and flexible than traditional systems because it uses internet protocol allowing you to switch between offices and locations. Integrating multiple systems and upgrading them also becomes an easier and quicker experience when going digital allowing you to expand with additional services and apps.

If you are a growing business, digital communications offer a much more scalable solution allowing your communication systems to grow with you, saving time and money in the process. You will also have the ability to monitor your usage and any important data more accurately, helping you deliver your services more effectively.

In Conclusion

This switch off should be the incentive for many to take the leap and start taking advantage of a digital technologies, enabling teams and employees and to get to grips with them in good time without the added pressure of the switch off looming.

If you need help and support migrating to new systems or want to explore the ways our technology services can enhance your business practices increasing efficiencies and reliability, please don’t hesitate to give us a call on 0333 344 6 344 or email us