Your phone system and your collaboration tools don't need to be separate things anymore. Here's a plain-English guide to Microsoft Teams Telephony — what it is, how it works, and whether it's right for your business.
Most businesses are running two communication systems side by side without ever questioning it.
There's Microsoft Teams — where your people chat, meet and share files all day. And then there's the phone system: a separate contract, separate hardware, separate numbers, often a legacy setup that predates half the team using it.
Teams Telephony closes that gap. It turns Microsoft Teams into your complete business phone system: real phone numbers, real call handling, all inside the app your team already lives in. No desk phones gathering dust, no juggling between systems, no separate PBX (private branch exchange) quietly costing you money in a comms cupboard.
With the UK's traditional phone network being switched off in 200 days' time, every business will have to move to internet-based calling sooner rather than later. The question isn't whether to modernise — it's what to move to. For businesses already using Microsoft 365, Teams Telephony is the option that deserves the closest look.
In simple terms, it adds full business calling to Microsoft Teams.
Your team can make and receive external calls (locally or internationally) to and from any normal phone number directly within Teams, on any device. Desk phone functionality without the desk phone: call queues, hunt groups, voicemail, call transfer, auto-attendants ("press 1 for sales..."), hold music, the lot.
Because it's built into Teams, calling stops being a separate silo. A phone call, a video meeting and a chat thread all live in one place, with one contact list, one presence status, and one app to learn. Someone working from home, on the road, or at their desk gets exactly the same experience.
This is where it can get jargon-heavy, so here's the short version.
Microsoft provides the Teams platform, but you still need a phone operator to connect your calls to the outside world — the equivalent of your phone line provider. Operator Connect is Microsoft's framework for integrating an approved operator, such as Gamma, directly into Teams.
Why it matters to you:
The practical upshot: you get a proper business phone system with none of the traditional phone-system baggage.
One system instead of two. One supplier relationship, one bill, one app for your team. The old PBX contract, maintenance agreement and ISDN (Integrated Services Digital Network) lines go away — and so do their costs.
Work from anywhere, properly. Your office number rings wherever your people are — on their laptops, mobiles, or headsets at home. Hybrid working stops being a compromise on call handling.
The switch-off is coming in 2027: The UK's analogue and ISDN phone networks are being permanently retired on 31 January 2027. If your phone system still relies on traditional lines, you'll need to move regardless — and moving to something your team already uses beats learning yet another platform.
Costs become predictable. Per-user monthly pricing replaces the mix of line rental, maintenance contracts and call charges that make traditional phone bills so hard to unpick.
It grows with you. Adding a new starter takes minutes in the admin centre, not an engineer visit and the installation of a new handset.
It's also worth knowing what happens if you do nothing. Lines that haven't migrated by the deadline don't simply carry on — at best, they fall back to a stripped-down emergency-only provision that supports none of the features a business phone line needs.
With around 2.8 million lines still on the old network — over half a million of them serving business premises — the final rush is coming, and the businesses that plan their move now will get a smoother migration than those forced into a last-minute scramble.
For most SMEs already using Microsoft 365, Teams Telephony — sometimes called Teams VoIP, since your calls travel over the internet rather than traditional phone lines — is a strong fit.
The honest questions to work through:
How does your business actually handle calls? High-volume reception desks, complex call routing, or specialist requirements (like call recording for compliance) all work in Teams Telephony — but they need to be designed properly rather than assuming default settings will do.
What's your current contract position? If you're mid-way through a phone system contract, the timing of a switch matters. Sometimes it's worth running down the clock; sometimes the savings justify moving early.
Is your connectivity up to it? Calls travel over your internet connection, so a reliable, well-configured network is the foundation. This is usually straightforward to assess — and fix — but it should be checked before you commit, not after.
Who's going to set it up properly? The difference between Teams Telephony done well and done badly is almost entirely in the setup: call flows, auto-attendants, emergency calling, and user training. It's worth having a partner who's been there and done it.
Netitude is a Technical Alliance Partner with Gamma, one of the UK's leading business communications providers and an approved Microsoft Operator Connect partner.
In practice, that partnership means our engineers work directly with Gamma's specialists on design, migration and support — so when we move a business to Teams Telephony, it's delivered by two teams who've done it together many times before, not a provider learning on your project.
It's also why we can offer honest advice on whether the switch is right for you: we know the platform's strengths and its limits.
We're running a free webinar on 13 August with our connectivity partner Gamma, covering exactly this — what Teams Telephony looks like in practice, how Operator Connect works, and the real cost and productivity case for making the switch.
This session is aimed at business leaders and organisational decision-makers looking to make smarter investment decisions in business technology. The webinar will include a live demonstration carried out by a Microsoft Voice Specialist (Matthew Mcleod, Gamma), and I'll be on hand to provide more context on this business connectivity solution.
Register your place here — or if you'd rather talk it through one-to-one, get in touch and we'll walk you through what the move would look like for your business. Or if you're still unsure about everything Microsoft Telephony, please check out our dedicated webpage for more info.
Can we keep our existing phone numbers? Yes. Your numbers are ported across to the new service, so customers and suppliers notice no change at all.
Do we need new hardware? Usually not. Most businesses run Teams Telephony through the devices they already have — laptops, mobiles and headsets. If you want physical handsets for reception or shared areas, Teams-certified desk phones are available.
What happens to our calls if the internet goes down? Calls can be automatically redirected to mobiles or another site, so a connectivity issue doesn't mean missed calls. This is part of designing the setup properly — and a good reason to have resilient connectivity in place.
Is Teams Telephony the same as Teams calling each other? No — standard Teams-to-Teams calls are free app-to-app calls, like a video meeting. Teams Telephony lets you call and receive calls from any external phone number, making Teams a full replacement for your phone system.
How long does it take to switch? For a typical SME, a well-planned migration takes a few weeks from decision to go-live, with number porting scheduled to avoid any downtime. Most of that time is spent on planning and design rather than on disruption.