Why UK Businesses Are Switching From ISDN To Cloud VoIP Right Now
Thinking about ISDN to VoIP migration UK but not sure where to start? You are not alone. Right now, thousands of UK businesses are asking the same thing.
Here is the thing. The old phone network is being switched off. Whether we like it or not, we all need to deal with it.
The good news? This is not just a forced upgrade. It is a real chance to fix your business telephony UK setup properly. With Cleartwo as your fully managed UK VoIP specialist, you get managed implementation, UK based support, Teams voice integration, enterprise level features at SME pricing and a 99.99% uptime SLA. No stress. We handle it.
The ISDN Switch Off Is Closer Than You Think
Let us tackle the big one first. The UK PSTN switch off is happening in January 2027. Traditional analogue lines and ISDN services are being retired for good.
If you are still using ISDN, those lines will stop working. No dramatic warning. Just silence. And nobody wants that on a Monday morning.
This is not a maybe. The move to digital voice services is confirmed.
If you have not looked into the deadline yet, our guide on what your business must do before the ISDN switch off explains it clearly. You can also read our PSTN switch off migration checklist for a simple action plan.
Between you and me, leaving this until 2026 is risky. Engineers will be busy. Porting delays will happen. Let us avoid the last minute panic.
Why Businesses Are Moving To Cloud VoIP Now
So why not just wait? Simple. Cloud VoIP is better. Once businesses see the difference, they rarely look back.
Hosted VoIP and cloud PBX systems use your internet connection to make and receive calls. No copper lines. No ageing hardware in a dusty cupboard.
With a modern VoIP phone system, you get:
- Lower monthly costs
- Flexible user licences
- Remote working support
- Call recording built in
- CRM integration options
- Microsoft Teams phone capability
- Advanced call routing tools
Honestly, ISDN cannot compete with that.
Cost Savings That Add Up
Let us be honest. Cost matters, especially for SMEs.
With ISDN, you pay line rental, call charges and maintenance. Often you also pay for separate support contracts. With hosted VoIP, costs are usually wrapped into one clear monthly fee.
Many UK businesses save up to 60 percent compared to traditional business telephony UK setups. Because it is cloud based, you are not paying for bulky PBX upgrades every few years.
Hybrid Working Is Here To Stay
Remember when everyone had to be in the office to answer calls? That feels like another era.
Cloud VoIP supports hybrid teams. Staff can use desk phones, softphone apps or mobile apps. Calls follow them wherever they work.
You may hear the term UCaaS. It simply means unified communications as a service. In plain English, it brings voice, chat and collaboration tools into one system.
If remote working is part of your plan, our guide on VoIP for remote teams shows you how to set it up properly.
Microsoft Teams Phone Integration
Over 300 million people use Microsoft Teams. But on its own, Teams is not a full phone system.
With the right setup, you can connect your VoIP system into Teams using Direct Routing. This gives you external calling, full call control and business grade features inside the Teams app.
We explain this in our Microsoft Teams phone system guide. It is one of the biggest drivers behind ISDN to VoIP migration UK right now.
What Happens During An ISDN To VoIP Migration
Take a breath. Migration sounds scary. It does not have to be.
You might worry about downtime. Or losing numbers you have had for years. Or your team rolling their eyes at another new system. No judgment. These are normal concerns.
At Cleartwo, we treat it as a managed project. We plan it carefully and keep things calm.
- Audit your current lines and numbers
- Check broadband and network readiness
- Plan number porting
- Configure your cloud PBX
- Test before go live
- Switch with minimal downtime
Number porting means moving your existing numbers from ISDN to VoIP. Your customers keep dialling the same numbers. No disruption.
If you want a simple explanation, read our guide on what VoIP is and how it works.
Modern Cloud PBX Features That Make Life Easier
This is where things get interesting.
Cloud PBX systems do far more than provide a dial tone. They include features that used to cost a fortune.
Call Recording And Compliance
For sectors like finance and professional services, call recording is essential.
Modern hosted VoIP platforms include secure recording with GDPR friendly storage. Some also support MiFID II compliance for regulated firms.
CRM Integration And Automation
Ever wished your phone system would log calls into your CRM automatically? It can.
With proper CRM integration, your team sees caller details straight away. You can click to dial from inside the CRM. Call notes can log automatically. No more manual updates.
Call data can also feed into reports and automation tools. No spreadsheets needed.
SIP Trunking And Flexible Scaling
Some businesses use SIP trunking to connect existing on site systems to the cloud. Others move fully to hosted VoIP.
Either way, you gain flexibility and easier scaling. You also avoid legacy line issues later.
Why CallSwitch One Makes Sense
Let us talk about the platform behind the scenes.
Cleartwo delivers hosted VoIP and UCaaS services through CallSwitch One. We are proud CallSwitch One resellers.
What does that mean for you?
You get reliable infrastructure built for serious business use. You get advanced features and strong resilience without added complexity. As resellers, we provide direct UK support, competitive pricing and hands on setup. You are not left in a generic support queue.
Between you and me, some providers sell a licence and disappear. Cleartwo does not. We manage everything from day one and stay with you long term.
ISDN To VoIP And The Bigger Picture
Switching phone systems often leads to wider improvements.
Many businesses review IT support, IT security and other cloud systems at the same time. A cloud phone system works well alongside Microsoft 365 and modern workplace tools.
We often see clients combine VoIP upgrades with managed IT support. It keeps everything aligned and easier to manage.
If you want to explore further, read our complete guide to VoIP phone systems for UK businesses.
Frequently Asked Questions
When Is The UK ISDN Switch Off?
The UK ISDN and PSTN network will be fully switched off by January 2027. After that, analogue and ISDN lines will no longer work. Businesses must move to all IP telephony such as hosted VoIP or SIP trunking before the deadline.
Can I Keep My Existing Phone Numbers?
Yes, in most cases you can port your existing numbers to VoIP. Your provider manages the process. Customers continue dialling the same numbers without noticing any change.
How Much Can A UK Business Save?
Many SMEs report savings of up to 60 percent compared to traditional line rental and call charges. Costs are usually bundled into a simple monthly per user fee. This reduces hardware and maintenance costs.
Does VoIP Work With Microsoft Teams?
Yes. Using Direct Routing or similar integration, you can connect VoIP to Microsoft Teams phone features. This allows you to make and receive external calls inside Teams while keeping full cloud PBX functionality.
How Long Does ISDN To VoIP Migration Take?
Most migrations take between two and six weeks. It depends on the number of users and system complexity. This includes audits, number porting, setup and testing. With Cleartwo managing the project, downtime is minimal and carefully planned.
If you are still on ISDN, now is the time to sort it out. No panic. No jargon. Just a clear plan.
You have got this. And Cleartwo is here to help you move smoothly and confidently, without the last minute chaos.
