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29 January 2024

Goodbye PSTN means getting ready for what comes next. Move your B2B customers to mobile PBX, from the cloud.

Around the world, countries are planning to switch off and retire their Public Switched Telephone Networks (PSTN).  In the United Kingdom, for example, 2025 has been set as the date for what’s become known as “big switch off”. It’s big news, and a big step.

The PSTN, the traditional circuit-switched network used for transmitting analogue voice data over copper wires, has long been the backbone of global communications, a worldwide network of interconnected telephone networks that has allowed for communication between different parties. To understand the landscape related to retiring the switched network and the decisions it presents, it’s instructive to briefly consider its evolution.

A brief history of the PSTN

Historically, entire telephone networks were analogue. This meant copper wires ran from a premise (be it an office or home) to an exchange, then wires from exchange to exchange, and again wires from the last exchange to the destination premises. And so on. Notwithstanding amplification and other technologies like noise filtering or echo cancellation which were deployed within the mix, the original analogue signal handled transmission all the way through.

This changed in the 1980s when, in the core of the network, copper wires between exchanges were replaced with digital links. In so doing, exchanges at both ends of a transmission performed analogue-to-digital and digital-to-analogue conversion. The transmission between the user premises and the exchange remained analogue, but in between the links were converted to digital.

ISDN arrived as the extension of that digital conversion to the end-user premises. ISDN used the original copper wires but transmitted digital signals on them (rather than analogue). The required conversion was done on premises (depending on the exact architecture, by one or more of several different pieces of specifically purposed equipment). The underlying technology of ISDN was DSL (Digital Subscriber Line), which for the most part still used the core circuit-switched network of PSTN. Today, many businesses continue to use ISDN connections, even while many others have moved to SIP trunk connectivity across internet connections.

The big bang and what next?

With this evolution in mind, why the switch off? Why is the traditional PSTN infrastructure presently being sunset globally in favour of modern digital communication technologies?

In the main (although the timing is location specific and can differ from country to country), it’s driven by high-level factors such as cost savings, the ability to transmit data more efficiently, and the desire to take advantage of advanced communication features which the PSTN can’t handle. But as noted, the timeline and extent of PSTN shutdowns varies from country to country, and some regions may rely significantly on PSTN infrastructure for a while yet.

So where are we heading?

It’s not all plain sailing.

We can think of the PSTN’s sunset as a progressive change. But the switch won’t be all plain sailing. All those legacy devices we’ve invested in and have come to rely on to communicate won’t be able to connect anymore once the PSTN is switched off. Legacy analogue connections will be closed, as will any ISDN lines. They will be replaced by SIP connections.

SIP provides a standardised way for devices and applications to establish and manage sessions, making it a fundamental protocol in the modern landscape of Internet-based communication. Indeed, it’s already used in the network core and as the main session protocol for IMS-based networks – so it’s hardly new.

However, existing devices won’t be able to connect to the new network without specialised adaptors. For businesses with many such devices, that’s a challenge.

What’s the problem?

The question businesses face is, what’s the best way to move seamlessly into the new, post-PSTN world? Do we write off our legacy devices and infrastructure, or do you stick with it, which means absorbing the cost of migration via the necessary addition of the numerous adapters and routers that will be required to enable us to continue communicating?

Another way of putting it (and something to think about) is this: Has the time come to go all mobile?

Is the most logical and efficient answer to the how-to-transition question simply shifting to a fully mobile cloud PBX – forget legacy devices and leverage mobiles, at a stroke, eliminating a costly legacy and burden for any business (who really cares about their fixed phones – they may use them, but do they matter in the same way that mobiles do?).

And it’s not just fixed infrastructure that comes into play here; Gintel’s cloud PBX is mobile-native, so it doesn’t require an OTT client (although it can use one), but instead connects directly to the IMS of the operator and, through that, to mobile terminals and stations.

An added plus: it confers a degree of future proofing too. Already VoLTE compliance, better experiences can be delivered via mobile – and the step towards 5G is already handled by radios. So, no further device disruption, just natural replacement cycles.

Talk to Gintel

The PSTN shutdown is a broad topic, and, in this blog, we’ve touched on some of its cornerstones issues.

Gintel’s Cloud and Mobile PBX can help operators ease the transition for their customers to its replacement.

We already have deep experience of the transition. Many of our MNO and operator customers have been addressing this challenge – some with a combination of full fibre and mobile, others with a pure mobile approach.

If you’d like to learn more and discover how we can help you deliver the best solutions for your business customers. please get in touch!

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