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ARTICLE: Are We Switch Off Ready?

In 2017, Openreach announced its decision to retire its aging, legacy copper telephony network commencing with the switch-off of Public Switched Telephony Network (PSTN) and Integrated Services Digital Network (ISDN) services. This article, with input from Krucial, explores how organisations, particularly operators of critical national infrastructure (CNI), can ensure they are ready for PSTN and ISDN switch off.

Copper Retirement is Rapidly Approaching

Copper retirement is part of a broader transformation occurring within the UK telecoms sector to shift to IP and full fibre networks. The switch off date of December 2025 is rapidly approaching with the real risk of disruption of services and costly retrospective solutions if unprepared. Organisations need to ask themselves; are we switch off ready?

Organisations need to ask themselves; are we switch off ready?

The process of migrating from copper has already begun. Openreach began retiring unused equipment in 2020 and in September of this year sale of wholesale line rental (WLR) will end. WLR is a regulated wholesale service that uses the PSTN which is sold by Openreach to service providers who in turn offer telephony services to consumers.

However, many organisations still use PSTN and ISDN lines to deliver a number of use cases. For example, in our experience, one organisation identified 27 use cases that were dependent upon PSTN and ISDN, of which almost one third were redundant.

Common uses of PSTN and ISDN circuits include providing fixed voice telephony, controlling traffic signals, providing home broadband for remote employees, monitoring alarm lines, connecting to safety cameras, communicating with ePoS payment systems, fax machines and a vast array of other control, monitoring and communications systems.

Identifying the less obvious use cases

Where organisations face challenges are identifying the less obvious uses of copper networks. The water industry for example has depended heavily on PSTN lines to communicate with water sensors. These sensors collect water quality data and will require an extensive discovery process and capital budget to identify and replace all the legacy equipment.

Other public sector bodies such as social care rely on legacy systems to provide telecare services to the vulnerable elderly population.

Resilient Technical solutions

Although fibre is seen as the go to replacement option to support a move to digital services, and despite a fast paced momentum of fibre installation across the UK, fibre will not reach every premise by 2025. Alternative connectivity solutions such as satellite, 4G, public and private 5G networks, need to be considered to ensure effective and resilient migration of services in all areas.

In addition, organisations using cellular 3G will need to be cognisant of the sunsetting of 3G networks and consider the 3G and PSTN switch off in parallel. Vodafone have already commenced their 3G switch off at the beginning of this year, with other mobile network operators (MNOs) following suit.

A solution which contains multiple connectivity options can add resilience to any replacement system. Businesses and organisations all over the world are undergoing digital transformation to improve processes and efficiency – which requires constant access to data and information remotely.

Krucial offers a solution which combines cellular communications with satellite technology. This means that if the cell network fails, satellite takes over, while if power goes down or there’s no mains power, there are a wide choice of built-in power sources. The result of such a resilient system is that users always have the mission-critical intelligence required to respond quickly, reduce risk and make informed business decisions – beyond what is possible with PSTN and ISDN currently.

Krucial has developed a free e-book, PSTN switch-off: don't get cut off outlining in more depth resilient alternatives to PSTN and ISDN.

PSTN switch off readiness assessment

There are many other factors that need to be taken into consideration particularly by larger organisations and those operating CNI. It is to this end that Intelligens Consulting has developed a framework that identifies the key success factors in determining an organisation's readiness for switch off, as demonstrated below.

We developed a framework that identifies key success factors to determine switch off readiness

Organisations need to take various measures to ensure a successful migration process including dedicating project management resources, implementing a centralised inventory management system, engaging with suppliers, allocating sufficient refresh capital, securing board-level commitment, minimising supplier fragmentation, incentivise long-term investment, and reusing existing ICT infrastructure to minimise duplication.

To meet the December 25 deadline, any organisation with existing PSTN lines needs to determine their switch off readiness otherwise incomplete migration could result in widespread disruption to services. Along with understanding what systems are currently in place, it is an opportunity to review systems and processes and ensure resilience is built in to future solutions. It is also an opportunity to optimise costs by eliminating any redundant ISDN or PSTN circuits.


Intelligens Consulting is a telecoms and smart city management consultant to investors, operators and public bodies. We have worked with organisations to help them successfully navigate the switch-off process, having recently conducted a switch off readiness review for a major CNI operator.

Krucial is a technology company that helps businesses transform for the better, connecting them to the information they need, and making sure they stay connected—no matter what.

Please contact us on should you wish to discuss anything discussed in this article.


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