Everything You Need To Know About The ISDN Switch Off
The ISDN switch off is coming January 2027. We’ve created this page to help you avoid disruption to your phone line and remain compliant with the new way of communicating
Companies we work with
So, what exactly is the ISDN switch off and how will it affect me?
The ISDN switch off is part of a nationwide move to shut down the UK’s traditional phone network and replace it with fully digital alternatives. ISDN (Integrated Services Digital Network) has been around since the late 1980s, using copper lines to carry voice and data. But the technology is outdated and no longer fit for the way we work today.
If your business still uses ISDN lines — for calls, alarms, card machines, or other systems — you’ll need to switch to a VoIP phone system or internet-based service. Otherwise, when ISDN is switched off, those services could stop working. The good news? Moving to digital isn’t just about avoiding disruption — it unlocks better call quality, more features, and often lower running costs too.
When is it actually going to happen?
The full switch-off is set for January 2027 — that’s when ISDN and PSTN services across the UK will be permanently shut down. But key changes are already in motion.
As of September 2023, Openreach introduced a Stop Sell, which means you can no longer buy or install new ISDN or PSTN lines. From now until 2027, areas will gradually be migrated to digital services — and once your area hits the cut-off point, any remaining copper-based services will be deactivated.
So while 2027 is the final deadline for the ISDN switch off, the switch is already underway. The earlier you act, the smoother your transition will be.
- Weeks
- Days
- Hours
- Minutes
Is it going to hurt my bank balance?
Actually, it’s more likely to save you money in the long run.
While there might be some upfront costs for new equipment or setup — like switching to VoIP phones or upgrading your broadband — most businesses find that digital systems are cheaper to run. You’ll often pay less for calls, get rid of pricey line rentals, and reduce maintenance costs because you’re not relying on ageing copper infrastructure.
Plus, digital phone systems usually come with features included — like call forwarding, voicemail to email, or video calling — which would’ve cost extra on older setups. So while it’s a change, it’s one that tends to pay off pretty quickly.
Why does the ISDN switch off need to happen anyway?
In short: the network is old, expensive to maintain, and no longer built for how we communicate today.
ISDN and PSTN were great in their day, but they rely on analogue copper wires, which are now decades old. As more businesses move to cloud-based systems, video calls, and mobile-first tools, the old network just can’t keep up — and it’s costly to keep patching it.
The new all-digital network uses internet protocol (IP) to deliver faster, more reliable, and more flexible communication. It’s easier to manage, scales with your business, and is far better suited to how we work today — whether that’s from the office, home, or somewhere in between.
Okay, I’m starting to get it… But what do I need to replace it with?
You’ll need to switch over to a cloud telephone system. This is something that can be easily handled for you, using a provider such as B4BC, however the further in advance you do it, the better.
Leading up to the ISDN switch off taking place a large number of organisations will be rushing to switch to a VoIP service to save their phone lines, which could easily create large delays across the country. Save yourself the hassle, get ahead of the digital stampede and get switched over as soon as you can.
What do I need to do for my business to be ready for the ISDN switch off?
Start by reviewing everything connected to your phone lines. That includes desk phones, fax machines (if you’ve still got one), alarm systems, card machines, entry systems — anything that still runs through ISDN.
Once you’ve got a clear list, speak to a trusted provider (like us at B4BC) to find out what needs upgrading and what can be migrated to digital. You’ll also want to check that your internet connection is strong enough for VoIP — if not, it may be time for a broadband upgrade too.
The sooner you get started, the smoother the switchover will be — no panic, no downtime.
Could I lose my telephone number?
No — as long as you port your number properly, you can keep it.
When switching from ISDN to a digital service like VoIP, your number doesn’t just disappear. Most providers will help you transfer (or “port”) your existing number over to the new system, so your customers can still reach you the same way they always have.
Just make sure you don’t cancel your current line before porting is complete, or you could lose the number. If you’re unsure, speak to your provider before making any changes — they’ll guide you through the process.
What happens if my broadband goes down?
Good question — because VoIP runs over the internet, a broadband outage would take your phone service down too.
That’s why it’s smart to have a backup plan. Some businesses install a second internet connection or keep a mobile phone system on standby. Others use call forwarding rules so that if the broadband drops, calls automatically redirect to a mobile or another location.
It’s all about having the right setup. With the right provider, you can build in fail-safes so you’re never left without a way to communicate.
Can I make changes to my existing setup before the ISDN switch off?
Absolutely — and in many cases, you don’t need to start from scratch.
If you’ve recently invested in business phones, routers, or network hardware, there’s a good chance some of it can still be used with a digital system. Many modern handsets, for example, are VoIP-ready or can be adapted with a small upgrade.
A good provider will review your current setup and let you know what can be reused, what needs updating, and how to make the transition as smooth and cost-effective as possible. It’s not all-or-nothing — it’s about working with what you’ve got.
What if I don’t have fibre in my area?
No fibre? No problem — you’ve still got options.
While fibre broadband is ideal for VoIP, it’s not the only way to get connected. You could use a 4G or 5G connection, a leased line, or even FTTC (Fibre to the Cabinet) if it’s available in your area. It all depends on how many users you’ve got and how much bandwidth your business needs.
We can help you find the best setup based on what’s available locally — so even if you’re not in a fibre area just yet, you won’t be left behind.
Why “I’m just going to wait” isn’t the best idea…
It might be tempting to hold off — after all, 2027 sounds like ages away. But in reality, the switch-off is already in motion.
The Stop Sell happened in September 2023, which means no new ISDN or PSTN services can be added. Many areas are already being moved over, and the closer we get to the deadline, the more demand there’ll be for engineers, support, and installation slots.
Leaving it too late could mean rushed decisions, downtime, or limited options when you need help the most. Switching early gives you time to plan properly, test everything, and make sure your business is fully future-ready — without the stress.
If you have any more questions about the ISDN switch off or want to discuss your options, feel free to get in touch.
Best 4 Business Communications
Address
2235-2243 Coventry Rd, Sheldon, Birmingham, B26 3NW
Phone Number:
Email Address:
