PSTN Switch Off Explained: All You Need to Know About 2025

What is the PSTN switch off?

Back in 2017, BT Openreach announced the PSTN switch off. But what does it mean? PSTN stands for Public Switched Telephone Network (PSTN) and the switch off brings to an end the decades-old UK-wide analogue network. The switch off also includes the primitive 1990s-era Integrated Services Digital Network ISDN digital network.

Businesses make extensive use of PSTN and ISDN—they power:

• landline phone systems
• business-wide internal phone systems
• fax services
• alarm systems
• gate entry systems
• lift lines
• CCTV systems
• some internet connections

All of those PSTN and ISDN capabilities on which your business relies today, can’t be relied upon to work—or be available—after 2025.

The ‘switch off’ is actually something of a misnomer. The existing copper wires and fibre-optic cables will still be there. But they’ll be carrying digital signals, and their ability to transmit analogue signals will degrade over time, because the analogue network won’t be maintained. When something breaks in the analogue network, it won’t be repaired.

PSTN switch off date

The deadline for the PSTN switch off completion is 2025.

2025 isn’t the start of the process: in some parts of the country, the switch off has already happened, in the sense that new connections aren’t permitted. Later this year, and early next year, those locations will see existing PSTN and ISDN connections fully withdrawn.

When this was announced in 2017, few people took much notice: the date in question was 2025, seven years away. Now, though, 2025 is a lot closer—and businesses are starting to realise that they need to do something about it.

So what exactly should your business do to prepare for the switch off? Your business will have to go digital.

What should you do to prepare?

Put simply, it makes sense to not only start thinking about the PSTN and ISDN switch off now, but to actually make the switch to digital as soon as possible.

The capability exists now, and the opportunities offered by going digital are extensive.

Indeed, it’s the scale of those opportunities which largely propelled BT’s switch off decision in the first place. The PSTN and ISDN networks were increasingly difficult and expensive to maintain, but the higher bandwidth offered by digital technology simply enables businesses to do so much more.

Hybrid working, video calls, collaboration technologies such as Microsoft Teams and Zoom, improved video and voice quality, file-sharing, greater reliability, ease of integration in terms of instant messaging, social media, and CRM… the list is long.

The benefits of going digital

Now, you’re perhaps thinking: does our business really need all those capabilities? We think that the best analogy for the switch off is the introduction of broadband in the UK, twenty years ago.

At the time, a lot of consumers and businesses remained on dial-up Internet connections—because they didn’t appreciate quite how rich and useful the capabilities of an ‘always-on’, high-bandwidth broadband connection were. Now, that naivety seems laughable—but at the time, the ‘Do I really need broadband?’ mentality was surprisingly common.

Digital telephony is much the same. Early-movers will gain competitive advantage; businesses that are laggards will lose it. So being an early-mover makes sense.

And by going digital now, rather than later, your business will also avoid the widely-anticipated problems and difficulties associated with the switch off. Being unable to augment or upgrade existing PSTN and ISDN services as BT withdraws them from sale; bottlenecks and lengthy waits as increasing numbers of businesses make the switchover, and potential equipment shortages.

The roadmap to digital

So how do you begin the transition to digital?

For most businesses, a three-stage process makes the most sense.

First, review the business’s current telephony needs. Which of its current services rely on PSTN or ISDN—voice telephony, CCTV, fax systems, door entry systems, alarm systems, and so on? How well does the existing telephony infrastructure currently serve the business, or are there un-met needs? And how will the PSTN and ISDN switch off affect the business’s technology roadmap?

Second, research the alternatives to PSTN and ISDN. As consumers, many of us are familiar with Voice over Internet Protocol (VoIP)—it’s how telephony services using desktop computers work. And for small and medium-sized businesses, VoIP could be a great solution. But there’s an alternative to VOIP: Session Initiation Protocol, or SIP. For larger businesses, SIP could well be the way to go.

And third, talk to experts. At Aspire, we’re helping businesses large and small to navigate the transition to digital telephony. Talking to us about how you’re currently set up will help us to understand how you work as a business, why you work that way, and what your future strategy is. Based on that, we’ll then be able to recommend the best course of action.

The PSTN switch off countdown has began

Remember: the advantages and opportunities of digital telephony are available right now. Waiting for the PSTN and ISDN switch off is one course action—but switching to digital earlier is likely to be a better course of action.

And the timescales are fast. Typically, we support businesses going digital in as little as six weeks from an initial exploratory call with us.

Why delay?