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06/11/2023 - Jodie Penk

The PSTN switch off decision was made by BT Openreach, in 2020 the PTSN switch off started. A 10 year plan was put in place and the role-out is now in full swing! The phase out began in 2020 and we are currently (2023) in the Stop Sell section of the timeline. 

Despite best efforts to keep the ISDN as modern as possible, with the ever-changing communications landscape being as diverse and flexible as it is, it started to become outdated and unreliable. In short, the ISDN could no longer compete with new technologies.

PTSN Business Switch Off Telephone
Photo by Julian Hochgesang

What is PSTN & ISDN?

Public Switched Telephone Network (PSTN)

The PSTN, also known as POTS (Plain Old Telephone System, was the first circuit-switched telephone network. This network has been in general use since the 1800’s and it has provided the infrastructure and services for public communications ever since. Using copper wiring, the traditional phone line was designed to carry voice-oriented communications via analog-based interconnects. The PSTN provides the physical infrastructure needed to make and receive phone calls between users by routing calls to their desired location via their international prefixes and area codes. 

 Integrated Services Digital Network (ISDN)

The ISDN is a set of communication standards for digital telephone connections and the transmission of voice and data over a digital line. The ISDN provides high-speed, high-bandwidth channels to every user on the Public Switched Telephone Network and enables a variety of mixed digital transmission to be accommodated via a single interface. The ISDN was introduced in 1985 and quickly became the preferred communication protocol amongst many businesses due to its ability to transfer data faster, increase call quality and its ability to allow numerous simultaneous connections. 

What is the PSTN Switch Off?

In 2015, BT Openreach made the decision to bring the PTSN/ISDN to a complete stop. This is set to be one of the biggest communications changes we have seen during our generation and will change the way we all communicate. A 10 year plan was put in place and the roll-out is now in full swing! The phase out began in 2020 and we are currently (2023) in the Stop Sell section of the timeline. The PSTN Switch Off, is the official decommissioning of the Plain Old Telephone System.

Despite best efforts to keep the PSTN as modern as possible, with the ever-changing communications landscape being as diverse and flexible as it is, it started to become outdated and unreliable. In short, the PSTN could no longer compete with new technologies. Traditional PSTN lines often offer little flexibility and lead to businesses being tied to physical locations.

With businesses expanding globally and modern ways of working often meaning remote working, being tied to physical locations can hinder operations. This switch off however, does pose some major threats to the way many people communicate. Any device which is connected to the PSTN line will be out of service as of 2025 – this includes Phone Systems, Fax Machines, Door Entry Units and many more. 

The PSTN Switch off date

The official switch off date for the PSTN in the UK and many other countries is 2025.

The phase out began in 2020 with some countries being slightly ahead with a fully decommissioned PSTN network – The Netherlands, Germany, Sweden and Japan.

Business meeting about PTSN
Photo by Jason Goodman

Why are OpenReach switching PSTN Network off?

The PSTN has essentially been the ‘backbone’ of the UK’s communications network for decades and as the world has adapted to a more digital way of life, the PSTN has not. The current network is old and difficult to maintain due to its physical nature. The physical network then came with many issues as the world began to digitally evolve including, tying businesses down to physical locations, little to no flexibility and increased maintenance costs.

Maintaining these outdated systems is becoming increasingly expensive and these costs are now being filtered down to the end user. As well as the cost and the physical hardware becoming severely outdated, the PSTN network can not keep up with the demands of the modern world. End users are now searching for the ‘perfect’ all in one communication system which can be used from anywhere in the world, on any device, at anytime which is something that the PSTN was never designed nor intended to do. This has therefore led to the decision to switch off the traditional PSTN network and to make the leap to an all-digital infrastructure.

What devices and systems will stop working from the PSTN 2025 switch off?

To ensure that your communication services remain uninterrupted during the 2025 switch off period, it is essential that you upgrade your current system to a digital alternative. There are many day-to-day devices that rely on a PSTN connection, so it is crucial to check everything you believe may be connected to the network. There may be devices which you did not know were connected to the PSTN which is why it is always best to check your supplier/provider. This includes; Phone Lines, CCTV, Door Entry Systems, Credit Card Machines, Fax Machines etc. 

Card machine PTSN
Photo by Blake Wisz

Who is the PSTN & ISDN affecting?

When thinking about the upcoming switch off it is important to remember that it won’t just affect voice services, but also broadband services will require upgrading. This means that both businesses and residential customers will be affected by the switch. Most residential customers around the UK will not have to take action before the switch off as companies, such as Openreach, are currently busy rolling out the full fibre network. Businesses however, will need to research into which alternative will benefit their business best and which will prove to be the most cost effective yet modern solution for their business operations.

Residential Impact

For residential customers, the switch shall be fairly straightforward depending on whether they already have a broadband connection in place. This will be a simple switch, which will not affect any communications. If a residential customer does not however have broadband connection in place, many providers have committed to no extra charge for customers who wish to only have broadband in place to continue using landline phones. Residential customers will also be able to keep their current phone number and phone which will make the switch easier on many people.

Business Impact

The switch off will have a much greater effect on businesses due to the likeliness of their being more than just a phone line which will need to be migrated to the new digital network. Legacy services such as fax machines, telecare devices, lift phones and retail payment terminals will all require attention during the switch off. Most of the technology mentioned can be replicated and improved using digital alternatives however, some may not be which is where businesses may be required to research what options are available. The switch may also come with additional hardware cost’s if a business is currently running on legacy devices which will not be suitable for the switch off. 

Are OpenReach/BT providing replacements for the PSTN switch off?

Companies such as Openreach and BT will provide alternative digital replacements for the PSTN network mainly by installing full fibre cabling across the country. Despite this being a huge benefit for residential customers, businesses will require more.

This is where Fuse 2 come in! With over 30 years of combined telecommunications knowledge and a fully independent voice and data network, Fuse 2 can offer bespoke solutions for any business. We have committed over 8 years to ensuring customers that they will have a seamless and smooth transition when migrating their current services to digital methods.

Our main aim at Fuse 2 is to not only provide world class service (including follow the sun support from highly trained technical engineers), but to work with a customer to discover which solution suits their needs best.

Will the replacement fibre be more expensive?

The price of the switch to fibre will be different for everyone. Pricing can vary depending on what devices you may need to replace, the amount of staff and also how feature rich you would like the platform to be. However, this pricing is significantly less when compared to what the cost would be for the end user if the PSTN network continues to operate. It is also important to remember that when switching to fibre a small extra cost will get you many more benefits like faster speeds, better call quality and more advanced features.

Is fibre optic more expensive with PTSN
Photo by John Adams

What are alternatives for PSTN & ISDN?

There are a variety of different alternatives for the PSTN and ISDN however, the most popular is VoIP. VoIP is an advanced telephony option which has been used by small, medium and large businesses for many years. Whatever option you choose, rest assured VoIP and cloud based systems are adaptable, scalable and most importantly, modern.

What to do next for the PSTN Switch off

Research is key when considering your next steps for the PSTN switch off. It is important to assess your current system, what options are available in your area and also your budget. Many companies will use the switch off to their advantage by upping prices closer to the switch off date, so it is important to find a trustworthy company before the inevitable deadline.


For residential properties, the broadband provider in your area such as BT Openreach and Virgin Media will take care of all aspects of the switch off. Your provider will be in touch to discuss options in your area when it comes time for you to migrate.


At Fuse 2 we can offer a bespoke service from start to finish which is fully tailored to you and your business needs. With 30 years of combined industry knowledge and experience, we have been providing businesses with state-of-the-art cloud services for many years. To find the perfect solution for you, talk to the people who have been providing VoIP long before the switch off was on the horizon!

The Benefits of the 2025 PSTN Switch off?

In a nutshell, the PSTN switch off is going to modernise and simplify the way we all communicate by future-proofing the solutions we use. The switch off will offer many significant benefits including enhanced connectivity, greater global flexibility and improved security and reliability for both businesses and residential properties. The world is evolving with new technological advancements being created every day, so why are we relying on old communication technologies?

Talk to the Communication Experts

We’re a fully independent company that provides the same quality of service as a big brand, meaning you will always receive friendly and personalised customer service from us, with a focus on custom network solutions tailored to your specific needs.

Fuse 2 are now the official range holder of all iHub numbers. If you have any information regarding legacy iHub services please get in touch +44 330 088 0333