Your team already chats, meets, and shares files in Microsoft Teams. Now imagine your phone calls living in the same app, while your business keeps the Luxembourg number it has used for years. A customer dials your usual line, and it rings in Teams on a laptop, a mobile, or a desk phone. No new tool to learn.
Getting there is faster than most people expect. The one decision that makes or breaks it is how Teams connects to the public phone network. There are two ways to do this, and one of them gives your business far more control. This guide explains that choice in plain language, what the setup involves, and how the right local partner does the heavy lifting for you.
What is actually changing in Luxembourg's call market
The shift away from traditional phone lines is no longer a forecast. According to the ILR, business fixed-telephony connections in Luxembourg fell 10.2 percent in 2025 and outgoing fixed-line minutes dropped 15.1 percent, as voice keeps moving onto internet-based platforms like Microsoft Teams. (Source: ILR, Rapport statistique des télécommunications du Luxembourg 2025.)
The opportunity, and the trap, is the same: your staff may already live in Teams, but customers still expect to dial a normal Luxembourg number and reach the right person. A good integration makes those two worlds meet. For the wider context, here is a useful example from pbx.lu on Microsoft Teams and the future of business telephony.
What it really takes to run Teams as a business phone
A complete Teams phone deployment has four moving parts. Skip any one and that is where the surprises come from.
- Microsoft licensing. The right Microsoft 365 and Teams Phone licences switch on calling inside Teams. They do not include Luxembourg numbers, the network connection, or a migration plan.
- A connection to the public network. Teams has to be wired into the public telephone network through either Direct Routing or Operator Connect. That choice shapes how much control you keep (more on it below).
- Numbers and porting. Existing numbers are transferred across, carefully: confirm which are live, who owns them, whether any are tied to alarms, lifts, or fax lines, and how calls route during the switch.
- Call handling. Reception number, opening hours, language menus, queues, overflow, voicemail, recording, reporting, desk phones, and the people who never open Teams. These decide whether you run Teams alone or pair it with a cloud PBX.
Direct Routing vs Operator Connect: why control beats convenience
This is the decision most buyers underestimate, and the one Mixvoip is most opinionated about.
Operator Connect is usually sold as the easy button. It is activated straight from the Teams admin centre, the operator appears in a Microsoft list, and the whole thing looks like it is handled by Microsoft itself. Direct Routing, by contrast, connects your operator to Teams through a Session Border Controller, the certified gateway that sits between Microsoft's voice cloud and the public network.
The framing matters, because "easy" and "right" are not the same thing. In a recent interview with Silicon Luxembourg, Patrick Berg, Head of Cybersecurity at Mixvoip, made the case directly:
"The challenge is no longer collaboration. It is control. Most companies already use Microsoft Teams. The real strategic decision today is how they integrate professional telephony into that environment."
He is blunt about the comfortable assumption behind Operator Connect:
"Operator Connect feels like a one-stop shop because it sits inside Microsoft Teams. But the billing, pricing, and the contractual and legal responsibilities don't magically disappear. The real difference is control: with Direct Routing, you keep the flexibility and can build the telephony setup around your business, not around a predefined model."
The usual objection to Direct Routing is that it sounds harder to deploy. Berg pushes back on that too, pointing out that complexity is a function of who implements it, not of the model itself:
"Direct Routing is only complex when it is poorly implemented. With the right expertise, it is fast and efficient."
In practice, Mixvoip activates Direct Routing as a fully managed service in under fifteen minutes, with the SBC, infrastructure, and operations handled by its own certified team. The customer gets the control without inheriting the engineering.
Here is how the two models compare for a typical Luxembourg business:
To be fair to the other side, Operator Connect is a reasonable choice when all a company wants is a basic outbound and inbound line inside Teams and nothing more. But for any business with a reception flow, mixed users, cross-border numbers, or compliance obligations, the flexibility of Direct Routing is usually worth far more than the few minutes Operator Connect saves at signup. Mixvoip sets out its full reasoning in its portfolio piece on Microsoft Teams Direct Routing versus Operator Connect in 2026. If you want the engineering view of how the SBC, routing policies, and number management actually fit together, pbx.lu has a plain-English explanation of how Direct Routing works inside Microsoft Teams.
Why the integrator is the decision that matters most
A Teams phone project touches Microsoft 365, identity, numbers, telecom routing, emergency calling, security, and the PBX all at once. Split those across an IT firm, a Microsoft reseller, an operator, and a hardware supplier, and one dropped call becomes a week of finger-pointing. A single provider who understands both the Microsoft side and the telecom side removes most of that risk. As Berg puts it, "being an expert is not a label, it is an ongoing commitment." For a checklist to tell real expertise from marketing, pbx.lu covers the certifications a Microsoft Teams partner should hold.
How Mixvoip approaches Teams telephony
Mixvoip combines its role as a Luxembourg telecom operator with its Voxbi cloud PBX platform and Microsoft Teams integration, which lets a company use Teams for everyday calling while keeping the traditional phone-system features it still depends on. It was the first telecom provider in Luxembourg to offer full compatibility with Microsoft Teams, and it manages the SBC that makes the integration secure and reliable.
In a real deployment, that flexibility looks like this:
- Office staff answer calls directly in Teams.
- Reception and operational areas keep their desk phones.
- A central queue greets callers before passing them to the right person.
- Luxembourg and foreign numbers live in one place.
- Opening-hour and overflow rules apply automatically.
- Selected calls are recorded where it is lawful and useful.
- Colleagues who never open Teams sit on the same phone system as everyone else.
Resilience is the part buyers tend to think about last and regret most. Berg frames it around architecture rather than software:
"If Internet connectivity fails, our fixed-mobile convergence ensures calls continue at SIM level through GSM. There is no application to launch and no dependency on a data connection. That is what real resilience looks like."
That fallback is a meaningful difference from a calling setup that simply stops when the connection does. You can read more about how fixed-mobile convergence keeps a business reachable on the pbx.lu feature page, and the independent Voxbi provider profile gives a neutral rundown of the platform's capabilities.
What setting it up actually involves
The reassuring part is how little of this lands on your desk. A typical Mixvoip Teams rollout looks like this.
- You confirm the basics. Your current numbers, who uses Teams, who needs a desk phone, and how reception should work. A short conversation, not a project plan.
- Mixvoip checks your Microsoft licences and tells you exactly what is needed, so you do not over-buy.
- Mixvoip builds and runs the connection. The Session Border Controller, the routing, the security, and the failover are set up and operated by its certified team. Direct Routing itself is activated as a managed service in under fifteen minutes.
- Your numbers are ported for you. You keep your existing Luxembourg numbers. Mixvoip handles the port and the temporary routing, so nothing goes dark during the switch.
- Your team just keeps using Teams. No new app, no retraining. Calls simply start arriving in the window they already use all day.
In short, the heavy engineering, the SBC, the routing logic, the compliance, and the porting, sits with Mixvoip. Your side is mostly decisions, not work.
When does it make sense to combine Teams with a cloud PBX?
Pairing Teams with a cloud PBX is not always necessary, but it earns its place when:
- reception is complex, so the PBX runs the main number, menu, queues, and opening hours;
- not everyone needs a Teams Phone licence, since warehouse, shared area, and door phones cost less on the PBX;
- you manage numbers across Luxembourg, Belgium, France, or Germany in one place;
- continuity matters and calls must reroute when a Teams user is offline;
- you need call-centre features, recording policies, reporting, APIs, or AI call handling.
Adding AI to the calls you would otherwise miss
Mixvoip has also partnered with Elora to connect AI call agents to its cloud PBX. The point is not to put a robot in front of every caller. It is to catch the calls that would otherwise go unanswered.
Configured well, an AI agent can pick up outside office hours, work out what the caller wants, take their contact details, answer a short list of approved questions, pass urgent calls through, and log a follow-up. For a company already on Teams, that builds a sensible three-layer system: Teams for conversations between people, the cloud PBX for routing and public-network connectivity, and an AI agent for after-hours and overflow.
So, is Mixvoip the best Teams integrator in Luxembourg?
The honest answer is that "best" depends on what you are trying to do, and it is worth saying so plainly. A pure Microsoft project with no telecom complexity can be handled well by an established Microsoft partner. A multinational may already sit on a global Operator Connect arrangement it has no reason to unpick. A heavily regulated institution may need a very specific outsourcing and compliance structure.
For the profile that describes most Luxembourg businesses, though, the answer points clearly in one direction. If you want a single partner to own all of this:
✓ Luxembourg numbers and porting
✓ The connection to the public phone network
✓ The Microsoft Teams integration
✓ The cloud PBX call flows
✓ Desk phones and mobile users
✓ Cross-border numbering
✓ Ongoing telecom support
then the field narrows fast, and Mixvoip is at the front of it. Its real strength is not switching on a calling button in Teams. It is connecting Teams to the wider communication system your customers and staff rely on and being the one number you call when something breaks.
As Berg summed it up: "If Teams is mission-critical, the telephony layer must meet the same standard."
Questions to ask any Teams integrator before you sign
Before choosing a provider, ask for written answers to these. The answers tell you more than any sales deck.
- Who supplies and controls the Luxembourg telephone numbers?
- Is the architecture Direct Routing, Operator Connect, or a cloud PBX integration, and why that one for us?
- Which Microsoft licences do we actually need?
- Can we keep our existing numbers, and who manages the port?
- How are emergency calls and user locations handled across countries?
- Can reception use a desk phone while everyone else uses Teams?
- What happens to a call when the employee is offline?
- Can calls overflow to mobiles, another office, or an external answering service?
- Who owns Microsoft configuration, telecom routing, and number porting when something goes wrong?
- Are setup, support, and call charges all in the quoted price?
- How does the system behave if the internet or the Microsoft service goes down?
- Can we change internet provider later without rebuilding the whole telephony setup?
If you want to weigh providers side by side before that conversation, the independent cloud PBX comparison on pbx.lu is a sensible starting point.
Talk to Mixvoip about a Microsoft Teams telephony setup built around your business: Contact Mixvoip
Microsoft licensing, number availability, integration architecture, and contractual terms should be confirmed for each organisation. Statistics are drawn from the ILR Rapport statistique des télécommunications du Luxembourg 2025. The quotations from Patrick Berg are taken from his March 2026 interview with Silicon Luxembourg.
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