Beyond voice calls: adapting critical services for the PSTN switch-off

However, beyond telephony, many less visible but operationally critical systems, from alarms and telecare services to backup connections supporting Fire & Rescue Service mobilisation systems still rely on PSTN infrastructure.

As the switch-off deadline approaches, organisations are increasingly recognising that PSTN withdrawal is not simply about replacing phone lines. It also requires a broader review of critical systems and backup connectivity services that have quietly relied on PSTN infrastructure for decades.

For Fire & Rescue Services in particular, maintaining resilient and dependable communication is essential to supporting emergency response. As a result, many organisations are now adapting their station end and mobilisation systems while also reshaping wider communications infrastructure for future requirements.

Much of the discussion around PSTN withdrawal has focused on replacing traditional voice services with digital alternatives. However, the impact extends far beyond frontline telephony.

Across many sectors, PSTN connectivity still supports operational technologies and backup services that sit in the background of day-to-day operations. These systems are rarely noticed until they fail, but they continue to play an important role in maintaining safety and service availability, from lift emergency phones and telecare systems to station end mobilisation systems. 

In many cases, organisations are now uncovering hidden dependencies on PSTN infrastructure as part of wider digital transformation and network modernisation programmes. This is prompting a broader reassessment of how critical services are connected and supported moving forward.

Within Fire & Rescue Services, station end systems play a critical role between control rooms and fire stations in mobilising firefighters and resources during emergency incidents. These systems depend on highly available communication networks with both primary and secondary connectivity paths to maintain service should one connection fail.

Traditionally, PSTN lines have often been used as secondary bearers supporting these systems. With the PSTN network scheduled for withdrawal, Fire & Rescue Services are now reviewing how these backup connections can be modernised while still meeting the demands of frontline service environments. 

This transition is not simply about replacing ageing infrastructure. It is about ensuring emergency communications remain dependable, secure and adaptable for future communication needs.

To support this transition, many organisations are adopting wireless networking technologies using 4G and 5G connectivity to replace legacy PSTN-based secondary bearers.

These solutions provide dependable backup connectivity while offering greater flexibility and scalability than traditional fixed-line infrastructure. Wireless WAN technologies can support automatic failover between primary and secondary connections, helping maintain communications during network outages.

In rural or geographically challenging locations, wireless connectivity can also provide coverage where fixed infrastructure may be limited. At the same time, centrally managed networking platforms are helping organisations improve visibility and control across distributed sites through remote monitoring, automated patching and centralised configuration management.

Across Fire & Rescue Services in England and Wales, PSTN replacement programmes are already underway, with legacy secondary bearers at fire stations being replaced by 4G and 5G wireless connectivity supporting station end mobilisation systems.

These projects are demonstrating how migration programmes can move beyond simple like-for-like replacement. Through centrally managed wireless networking platforms, services are gaining a clearer view of their communications infrastructure.

The experience is also reinforcing the importance of early planning. Identifying hidden PSTN dependencies within complex operational environments takes time, and organisations that begin assessments early are better placed to manage the transition without disruption to frontline services.

As Fire & Rescue Services modernise operational connectivity, many are also using the opportunity to prepare for wider future communications requirements.

Rather than implementing a direct replacement for PSTN lines, organisations are increasingly using connectivity modernisation to strengthen long-term service availability. Modern wireless networking solutions can help create more adaptable communications environments that evolve alongside changing service needs.

This challenge extends well beyond emergency services. Healthcare organisations, universities, transport environments and public sector estates all continue to rely on systems supported by PSTN infrastructure. For many, the switch-off is becoming a catalyst for wider infrastructure modernisation and greater oversight of critical communications services.

As the 2027 PSTN switch-off deadline approaches, organisations are moving beyond traditional telephony replacement and taking a broader view of how operational services are connected and supported.

For Fire & Rescue Services and other organisations operating critical infrastructure, the transition presents an opportunity to strengthen resilience, modernise connectivity and improve visibility across operational systems.

The experience of Fire & Rescue Services highlights how wireless networking and centrally managed connectivity can help organisations strengthen critical communications while preparing for the post-PSTN era.