Move off ISDN before the PSTN switch off forces the issue — same phone numbers, a managed timeline, and a modern VoIP or Microsoft Teams phone system in their place.
Your existing phone numbers move across to your new VoIP platform, so customers and suppliers can keep calling the number they already know.
We plan your migration to a timeline you control, rather than leaving it until the network is switched off around you.
Multiple offices running different generations of ISDN lines move to a single, consistent VoIP platform, managed centrally.
ISDN — Integrated Services Digital Network — has carried business phone calls in the UK for decades, but the underlying PSTN network it depends on is being retired, and ISDN lines are being withdrawn as part of that process. ISDN to VoIP migration UK businesses are working through right now isn't optional in the long run: once your provider withdraws ISDN service, any phone system still relying on it stops working, regardless of whether a replacement has been arranged. VoIP — voice calls carried over your internet connection rather than a dedicated phone line — is the direct replacement, and for most businesses it's a straightforward like-for-like swap in terms of what staff experience day to day: the same phone numbers, the same call handling features, often better mobile and remote working support, running over broadband instead of a legacy ISDN circuit. The businesses that struggle with this migration are almost always the ones that leave it until their provider forces the timeline, rather than the ones that plan it on their own schedule with time to test, train staff and fix issues calmly before anything actually depends on the new system. It's also worth separating two things that get confused: the PSTN switch off affects the underlying network ISDN and analogue lines run over, while VoIP is a choice of platform that replaces them. You're not just swapping one type of phone line for another — you're generally gaining features that traditional ISDN handsets never offered, including calling from a mobile app when out of the office, voicemail delivered straight to email, and call routing that can be reconfigured in minutes rather than requiring an engineer visit to reprogram a physical exchange.
Every UK business running ISDN lines will move to VoIP eventually — the only real choice is whether that happens on a timeline you control, or one dictated by network withdrawal notices arriving with less warning than you'd like.
Planning your migration now means choosing your own cutover date, testing the new system properly, and training staff before anyone's actually relying on it for live calls.
Number porting means customers and suppliers keep calling the number they've always used, even though the underlying technology carrying the call has completely changed.
Alarm dialers, lift emergency lines, older card payment terminals and fax machines are often still quietly wired to an ISDN or analogue line — migration planning has to account for all of it, not just the phone handsets on people's desks.
From line audit to a fully live, tested VoIP phone system.
We identify every ISDN and analogue line across your business, including anything beyond desk phones still wired to the old network.
A clear, staged plan with a cutover date you choose, giving time to test and train before anything depends on the new system.
Existing phone numbers are ported across to your new VoIP platform, so callers never notice a change on their end.
Your new phone system, whether standalone VoIP or Microsoft Teams calling, is configured and staff are shown how to use the features that matter to them.
24/7 monitoring of your voice platform and connectivity, backed by our support team and a 99% SLA guarantee.
We don't just look at the phone system on people's desks — we check what else in the building is quietly wired to the old network, so nothing gets disconnected by surprise.
Your team knows exactly when the switch happens, has been trained on the new system beforehand, and has a fallback plan in place for the changeover itself.
From line audit to a fully live VoIP phone system, on your timeline.
We map every ISDN and analogue line in use, including anything beyond desk phones connected to the old network.
You receive a clear timeline and fixed quote covering porting, platform setup and training, agreed before work begins.
Numbers are ported and the new system goes live on your chosen date, with the old lines kept available until cutover is confirmed working.
24/7 monitoring and our support team keep your new phone system running, backed by a 99% SLA guarantee.
We audit every line in the building before we plan anything, so nothing wired to the old network gets disconnected as a surprise once cutover happens.
Number porting is handled as standard, so your existing phone numbers move to the new platform without customers or suppliers ever noticing a change on their end.
We plan cutover for a date you choose, with the old lines kept available until the new system is confirmed working, rather than switching everything at once and hoping for the best.
Our 99% SLA guarantee and 24/7 monitoring mean your new VoIP platform is watched around the clock, with issues caught before staff notice a dropped call.
Staff training is included, covering the features people actually use — call transfer, voicemail to email, mobile app calling — not just a technical handover nobody reads.
As part of our wider connectivity and VoIP services, we can combine your ISDN migration with a SOGEA broadband upgrade in one coordinated project, rather than treating them as two unrelated jobs from two different suppliers.
We also make sure your internet connection can actually carry voice calls reliably before cutover — checking bandwidth, prioritising voice traffic where needed, and arranging 4G or 5G failover for businesses that can't afford any gap in phone coverage, rather than assuming the existing broadband will simply cope.
The PSTN switch off 2027 UK deadline refers to the phased withdrawal of the UK's traditional analogue and ISDN phone network, exchange by exchange, as providers move the whole country onto digital, internet-based voice services. In practice this means the ISDN or analogue lines many businesses still rely on for phone calls, alarm systems or card payment terminals will stop working on a schedule set by network providers, not by individual businesses. Some exchanges move earlier than others, and businesses that wait for a formal withdrawal notice before acting often find themselves with less choice over timing and less room to test a new system properly before it becomes essential. Planning your ISDN to VoIP migration now, well ahead of any deadline that applies to your exchange, means you control the schedule, not the other way around — and if you're also moving broadband to SOGEA, the two projects sit naturally together. Regional and exchange-by-exchange timing varies, and providers don't always give businesses as much individual notice as you'd expect for something this disruptive — which is exactly why we recommend starting the conversation well before you've received a withdrawal notice, rather than treating that notice as the starting gun.
A migration planned on your timeline, not the network's.
We check what else is wired to the old network, not just the phones on desks.
Existing numbers move across with no disruption for callers.
The old lines stay live until the new system is confirmed working properly.
Your new voice platform is watched around the clock from day one.
A real, contracted commitment behind the phone system we manage for you.
Your team is shown how to use the new system before it goes live, not after.
We sequence migration across sites so no location is left dependent on a system nobody's tested.
A named point of contact who understands your migration, not a rotating support queue.
A fixed quote covering porting, platform setup and training before any work begins.
We deliver ISDN to VoIP migration UK-wide, coordinating line audits, number porting and platform setup remotely, with on-site support available from our City of London base wherever hands-on work is genuinely needed. Multi-site businesses get a single, consistent migration plan across every location, regardless of how many different generations of phone line each office happens to be running today. Whether your offices sit in one city or are spread across the country, the same audit-first, cutover-on-your-terms approach applies everywhere we work.
Start with a proper line audit rather than assuming the only thing on ISDN is the office phone system. Alarm dialers, lifts and older payment terminals are commonly still wired to the old network, and missing one during planning is how businesses end up with an unexpected outage after cutover.
Don't wait for the notice: planning now, ahead of any formal withdrawal notice for your exchange, gives you far more control over timing, testing and staff training than reacting once a deadline has already been set for you.
Getting started: we offer a free consultation to review your current lines and map out a realistic migration timeline and fixed quote.
Multi-site businesses: if different offices are on different providers or exchanges, migrating in a sequenced order — rather than all at once — usually gives a smoother rollout and lets lessons from the first site improve every one that follows.
Deadline
ISDN and analogue lines are being withdrawn UK-wide. Migrate on your own timeline, with numbers ported and staff trained before cutover.
isdn to voip migration uk
Planned migration off ISDN and analogue phone lines ahead of the PSTN switch off, with number porting, staff training and 24/7 monitoring.
sogea broadband business
Fibre broadband without a dependent phone line — the natural connectivity pairing for a VoIP-first phone system.
Got questions about ISDN to VoIP migration? We've answered the most common ones below. If you need more detail, get in touch.
It refers to the phased withdrawal of the UK's traditional analogue and ISDN phone network, exchange by exchange, as providers move the country onto digital, internet-based voice services. Once your exchange is switched, any equipment still relying on ISDN or PSTN lines stops working.
You can wait, but doing so means the network's withdrawal timeline decides when you migrate, with less notice and less time to test a new system properly. Migrating on your own schedule gives you far more control over cutover, training and any issues that come up.
Yes, number porting is a standard part of the migration — your existing numbers move across to the new VoIP platform, and callers won't notice any difference.
Cost depends on the number of lines, sites and any extra integration work needed. We give a fixed quote after a free consultation and line audit, so there are no surprise costs once migration begins.
We keep old lines active until the new VoIP system is tested and confirmed working, minimising the risk of a gap in phone coverage during the actual changeover.
Yes, we can either migrate multiple sites together or sequence them one at a time, depending on what fits your business — either way, every site ends up on one consistent, managed VoIP platform.
Our line audit specifically checks for equipment beyond desk phones that's wired to the old network — alarm dialers, lifts and older payment terminals included — so a replacement is planned for each before cutover, not discovered afterwards.
Your phone lines stop working once your exchange is switched, with no fallback until a replacement system is in place. Migrating proactively avoids that risk entirely and gives you time to fix any issues before they affect live calls.
Limited time offer — valid until 31/05/2026
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