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ISDN switch-off: How to future-proof your business

By 2025 legacy ISDN and PSTN telephony networks will be switched off for good. If you aren’t using an IP (internet protocol) telephone system already, you should start making plans for the ISDN switch off now, so you won’t be forced into panicky decisions nearer the time.

The transition to an all-IP network means that, from December 2025, all voice data will need to travel over your internet connection, as it already does if you make a Skype or Teams call. There will no longer be an analogue option.

The fact is that these legacy systems are simply not designed for the kind of data-rich communications that are increasingly crucial to modern business. So, the sooner you make the switch to all-IP communications, the sooner you’ll start seeing the benefits.

Farewell to ISDN and PSTN

Change can be unsettling, and the ISDN switch off represents the biggest shake up to telecoms in 30 years. But it needs to happen because modern, all-IP communications are simply more efficient, more flexible and more cost-effective than their legacy counterparts. Businesses are recognising that already, which is why the transition is gathering pace well ahead of the switch off date. For example, around 40% of UK business lines have already moved to Hosted Voice, a cloud-based all-IP solution.

Meanwhile, the sales of ISDN and PSTN services have already been stopped in a number of areas, as part of the stop-sell. From September 2023 you won’t be able to buy new ISDN or PSTN lines anywhere, with the final withdrawal of services scheduled for December 2025. These dates will creep up before you know it. Many businesses, and doubtless many of your competitors, are already eyeing up the best alternatives to their current legacy systems. Don’t be left behind.

What does this mean for your business?

The switch-off could affect over 2 million UK businesses, primarily SMEs who still operate on ISDN. If you’re one of the businesses still using landline telephones and fax machines, the switch-off will dramatically impact your operations. You’ll need to figure out how this situation will change how your staff communicates with clients, customers, partners, and vendors and how you’ll cope with that change.

While 2025 may still seem a long way off, we strongly advise businesses to not wait until the last minute to make a change to all-digital communications such as cloud telephony or hosted PBX.

It’s time to change

So, it really is time to start making plans around your future telephony and communications needs. The sooner you do, the more time you’ll have to pick the VoIP (Voice over Internet Protocol) solution that’s exactly right for you. Panicked decisions, taken in haste, rarely work out for the best.

And there are some important decisions to be made. IP communications solutions come in various flavours, with different benefits and costs, so you do need to do some homework.

For example, a Hosted Voice system puts all your telephony infrastructure in the cloud, making it accessible from anywhere and on any device, and entirely replaces your legacy ISDN and onsite PBX. SIP Trunking also offers next generation voice technology and can often be used with an existing PBX and your current handsets. Both options can offer Unified Communications (UC), which integrates voice, video, chat and other multimedia communications into one seamless solution.

That integration is the huge advantage of modern internet-based communications, especially for remote workers, but you don’t have to have it if you don’t have the need. Basic VoIP services offer the simplicity and cost efficiency of internet telephony without any added extras.

Get ahead of the communications curve

There’s another reason that now is the right time to review your communications needs. The last few years has seen a huge upswing in the take up of new technological solutions, as firms have been forced to equip remote teams with the tools and services they need to work productively from home.

The fact is that IP-based communications are far more remote worker friendly than ISDN or PSTN. Using softphones or personal devices to make internet calls is a cost-effective and flexible way of equipping home-based workers. With UC solutions, homeworkers can access a full suite of communications and collaboration tools wherever they happen to be. All they need is a reliable internet connection.

Connectivity is another factor you need to consider, whatever VoIP option you choose. Routing voice and video calls through the internet takes up bandwidth. If your corporate network is already stretched, an upgrade to Full-fibre (FTTP) broadband or dedicated Ethernet can make sure you have the capacity and reliability for a new era of all-IP communications.

What exactly is Voice-over-Internet Protocol (VoIP)

In essence, VoIP is a technology that allows you to make voice calls using a broadband Internet connection – it’s basically making calls via the Internet rather than the traditional copper lines of the past. The introduction of Gigabit-capable, full fibre broadband has begun in the UK and is being rolled-out across the country as we speak. If your business already has a broadband Internet connection, it’s easy to add on a VoIP phone service and make calls. There’s no need to rent a line from a phone service and no complicated additional wiring. It can be as simple as plugging in your digital VoIP handset and you’re set to go. There are, of course, considerations that should be taken to achieve consistently good call quality and your service provider should be able to review the performance of your broadband connection and make appropriate recommendations to ensure it is suitable for VoIP calls.

Need help making the switch?

We’re already helping lots of UK businesses transition from their legacy ISDN systems to our cloud-hosted phone system. If you need help making the switch, email us at or give us a call on 020 4599 1365

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