The public switched telephone network (PSTN), or analogue telephony, era in the UK is finally coming to an end after providing voice communications for over 100 years, with the final switch-off date currently set for December 2025. France, Germany, Japan, Spain, Singapore and Sweden are already ahead, with Estonia and The Netherlands completing the switch.

For many the deadline can’t come soon enough, since this copper-based network is simply unable to support digitised technologies we’ve come to depend upon. Universal Internet accessibility, together with global smartphone penetration exceeding 80%, has transformed the way people communicate, with landlines being just one of many different methods. Hence, it would be obvious to think that moving from analogue to a digital alternative is a straightforward process, involving plugging an existing phone into a new socket or a router.

As it happens, the practicalities of the switchover show that PSTN is the underpinning enabler to a lot more than just fixed-line telephony. Yet, according to Internet service provider Zen Internet, nearly a quarter of UK businesses are unaware of the PSTN impact and are simply not ready for the big switch-off.

The switch-off brings with it a whole host of infrastructure challenges, particularly for businesses and buildings reliant on this legacy network for the operability of devices and applications powering alarm lines, elevator lines, ATMs, POS, door entry systems, telemetry systems (flood defence, traffic lights), fax machines, pagers and telecare, to name just a few. After the cut-off point all of these services, and many more besides, will need to be IP compatible to continue working. Suppliers must therefore carry out testing to make sure that their associated products will continue to work on an All-IP network.

How to proceed best?

Although digital telephony is clearly the way forward, it does bring with it several infrastructure challenges. It also demonstrates the need for enterprises to implement a comprehensive wireless strategy to support current and future communications. Many organisations, smaller ones in particular, are still reliant on legacy communications networks for the operability of low-power technologies behind their setups.

For many services, Wi-Fi is a logical alternative as it is the backbone to digital transformation – and especially since all services including voice will be digital and require Internet connectivity.

But WiFi-only networks, no matter how sophisticated, will not resolve the switchover challenges in their entirety, and other channels including public cellular coverage, private cellular coverage and low-power sensor networks must also be carefully considered, this includes security issues. 

Many Wi-Fi setups, like PSTN, are also copper based, which causes speed and performance issues because of RF leakage. This is being addressed with the rollout of gigabit broadband, but the process is still ongoing in many countries with urban areas being prioritised.

Then, Wi-Fi signals are propagated via a series of access points, with quality of service being dependent on the proximity of a device/technology in relation to that access point. And the further away, the weaker the signal, especially if there are corners/corridors/stairwells to contend with.

Also, Wi-Fi access points present security weak spots that can easily be compromised, as many high-profile public sector organisations have found to their cost; such as, for example, the ransomware attack on Hackney Council’s communications network and the NHS security breach of 2017.

These examples are data-related but digital voice heightens the risk of malware attacks.

Wi-Fi access points, even those that meet the latest security standards, present security weak spots, heightening the risk of cybercrime and malware attacks. Although the latest Wi-Fi security standard (WPA3) overcomes many of these shortfalls, access points are still areas of weakness.

Another consideration is that of public safety. Whilst all legacy communications will be impacted to some degree by digitisation, utility companies and elevator suppliers are particularly susceptible and need to think about their wireless strategies now. Utilities are heavily reliant on legacy networks to control and manage their infrastructure – which is also in dire need of an update. Sites are typically remote and some are below ground, which must be factored in when assessing PSTN alternatives. 

Water and energy providers, for example, have historically used pagers and two-way radio systems to control and manage their infrastructure – not only must they overhaul their underlying comms infrastructure in line with next generation technologies, the legacy devices they currently depend upon are also being phased out further demonstrating the need for action.

AS for elevators, the critical application is their emergency communication line. Legislation mandates that all elevators must enable occupants to raise the alarm. Analogue lines, together with auto-diallers that respond at the push of a button, will need an alternative solution. 

All these applications will need to be replaced with digital alternatives, and Wi-Fi is not the right option here because of line-of-sight challenges. 

Cellular connectivity

The PSTN switch-off magnifies the need for robust mobile communications networks to operate alongside Wi-Fi. Not only do they offer a viable solution for rural communities that are not going to benefit from all fibre broadband anytime soon, they provide a straightforward and cost-effective means to operate smart building technologies. ` In essence, cellular networks support multi-network access via roaming or dual SIM enabling interconnectivity, are more secure than Wi-Fi, and require minimal hardware as far as IoT technologies are concerned, among others.

The downside, however, is that mobile signal strength deteriorates inside buildings. To provide the levels of coverage needed for people and machines to interconnect, the outdoor signal must be indoors, using supplementary equipment. Now that Ofcom has relaxed the rules pertaining to the use of mobile repeaters, their deployment is no longer the arduous task it once was. The only caveat is that said repeaters must tick several regulatory boxes, and not many do. 

With the imminent PSTN switch-off, cellular as well Wi-Fi must be factored into all technology/service migrations as a matter of course, since both are interdependent. Cellular also allows businesses to be future ready to support next generation services such as 5G, not to mention the country’s new public safety network which, incidentally, will also be cellular.

Apart from making the changeover seamless and helping enterprises prepare for Industry 4.0, accounting for the digital transformation within a complete wireless strategy allows businesses to be ready to support up-and-coming technologies, automation, as well as robotics operating on public 5G and/or private mobile networks.

By Colin Abrey, VP Strategic Accounts, Nextivity