Microsoft Teams Phone — Business Telephony
Your phone service at Teams. Without losing your touch.
Teams is already in your facility. The question is no longer whether to integrate telephony into it, but how. Connection to the carrier, numbering plan, session controllers, emergency calls, analog phones, DECT, rooms, and continuity of service in the event of an outage: these are the factors that make the difference between a successful project and a PBX that goes down on a Tuesday morning.
The choice of connection determines your flexibility for years to come. With your own session controllers, switching providers takes just an evening’s work. With a connection fully managed by the provider, it’s a project that migration — and you’ll find that out when it’s time to renegotiate.
What has changed since your last review of the topic
Teams Phone is no longer just an option for the future. It's the only way forward.
Many organizations looked at Teams Phone in 2020, decided it was missing some features, and put off making a decision. What was missing has since been added, and what remained has been phased out. Here are the four key factors that matter.
October 14, 2025
Skype for Business Server is no longer supported
Support for the 2015 and 2019 versions has ended, with no paid extension period. The only two supported options are Teams Phone or the on-premises Subscription Edition.
Since 2024
Contact centers connect natively
Microsoft has introduced three certified integration models. A contact center can now be integrated into Teams without requiring a second phone or a second app for the agent.
2025 and 2026
AI Enters the Call
Automatic notes, key moments, action items, live transcription, and live translation are coming to phone calls. These features require a Copilot license: it’s a cost, not just a box to check.
Today
The focus is no longer on the platform
It involves the connection, the numbering, and the operation. In other words, it’s exactly what no one shows in a demonstration—and exactly what causes projects to fail.
The practical implication: a Teams Phone project is not a Microsoft 365— it’s a telephony project. It must be planned as such—with a numbering plan, an emergency call procedure, and a fallback plan—otherwise, you’ll pay the price on the first Monday morning.
View ConnectionsThe decision that shapes everything
Four ways to connect Teams to the telephone network.
This is the first decision you’ll make in a “ Teams Phone” project, and it’s the one that commits you for the longest period of time. It’s not based on a pricing plan—it’s based on who will be in control.
Direct routing, using your session controllers
Your own controllers connect Teams to the carrier of your choice. This is the most flexible solution—and the only one that allows you to keep your analog phones, your DECT system, and your existing PBX during the transition. It’s the one we recommend most often.
Our Session ControllersOperator Connect
A certified service provider connects to your client Teams from the administration console. No installation required; setup takes just a few days. In exchange, the service provider manages the infrastructure—and you rely on it.
Microsoft Calling Plans
Microsoft acts as your carrier and bills you for the minutes used. It's the easiest option to set up, with no choice of carrier and no room for negotiation. Suitable for small areas and remote locations.
Teams Cell Phone
The mobile number becomes the business number, ported by the mobile carrier. This is ideal for professionals who work in the field. Please note: This service covers only user numbers, not service numbers such as an automated switchboard or a call queue.
And most often: both at the same time
A single client— Teams —supports multiple parallel connections. This is a configuration we set up regularly: a certified operator for individual branches, and your session controllers at headquarters, where DECT, analog, and the contact center all operate.
Our recommendation, and why
Keep your session controllers. That's what gives you freedom.
We put ourselves in the customer's shoes, and that's evident in this piece of advice: it would mean we'd sell fewer licenses and more engineering services. We give it anyway, because it's the kind of advice that stands the test of time over five years.
A session controller is a box that speaks two languages: the language of Teams and that of your service provider. As long as you have one, switching service providers is as simple as changing a configuration and switching a connection. An evening’s work—all planned out.
If the operator is responsible for this role, switching operators once again becomes a migration project: new connections, new tests, new acceptance testing, and a new switchover window. You don’t find this out when you sign the contract; you find out three years later, when it’s time to renegotiate—that is, at the worst possible moment.
The session controller also serves other purposes, and it’s often the one that calls the shots: it keeps non-communicating devices running Teams. Analog elevator control panels, door phones, alarms, warehouse DECT systems, and legacy PBXs during the transition. Without it, these devices would require replacement.
The honest truth is this: this solution requires expertise—either yours or ours. A certified service provider is less expensive to operate and can be set up more quickly. For a small business with thirty employees and no specialized equipment, this is often the right choice—and we’re not afraid to say so.
How Much Each Option Costs You in Terms of Freedom
- Your SBC Maximum freedom Choose your service provider at each renewal; use multiple providers simultaneously; automatic failover from one to the other. You keep both analog and DECT service.
- SBC hosted Moderate freedom The service provider hosts the controller. Less operational work for you, but a long-term contract and an exit that requires planning.
- Operator Connect Limited freedom Quick setup and hassle-free operation. Switching carriers means reconnecting your service and transferring your numbers.
- Microsoft Plans No choice of carrier Simple, predictable, and with no room for negotiation on the per-minute rate. Acceptable on a small scale, but expensive on a large scale.
The contract trap: The three-year commitment signed with the service provider isn’t listed in the integration quote. Always ask how much it costs to cancel the contract before signing up—we’ll ask that question for you if you’d like.
The actual scope
Teams Phone isn't just about giving people a phone number.
Assigning numbers takes a day. What takes time on a project is everything else that goes along with it—and that’s exactly where the issues arise in the weeks following the switchover.
| Other Issues to Address | Why It Matters | The Trap |
|---|---|---|
| The Numbering Plan | Why? Numbers, prefixes, standardization rules, short internal calls, and backup routing—these are what ensure a call reaches the right destination. | The Pitfall: The former center back’s system has drifted off course for fifteen years. Adopting it as is would mean bringing fifteen years’ worth of stopgap measures into a new system. |
| Emergency Calls | Why?A mobile phone is no longer tied to a specific address. Call routing and caller location must be designed from the ground up, not inherited from legacy systems. | The Trap: This isthe point you realize the day someone dials 144. It’s tested, site by site, and the test is documented. |
| Analog and DECT | Why? Elevators, intercoms, alarms, a notary’s fax machine, warehouse or hospital handsets—these devices don’t use Teams and aren’t going anywhere. | The Trap:They’re invisible in a license inventory. You discover them while walking down the hallways—and without a session monitor, they become a replacement budget item. |
| The Switchboard and Queues | Why? The greeting, call overflow, hours of operation, holidays, announcements, and night call forwarding—these are the first things your customers hear. | The Trap:No one knows how today's system works anymore. You learn how it works by listening to the experts, not by reading about the old switchboard. |
| Survival in the Event of a Power Outage | Why, whenthe website's internet connection goes down, the phone service goes down with it: that's the price you pay for a service in the cloud. | The Pitfall: Thiscan be addressed—on-site life support equipment, a secondary anchor point, or assistance from another operator—but only if it was planned for during the design phase. |
| Posts, helmets, and rooms | Why? It’swhat the user experiences, and what they use to judge the project—regardless of the quality of the architecture. | The Catch: Someexisting positions can be bridged, while others cannot. The assessment is done at the beginning, when there is still money left in the budget. |
| The Contact Center | Why: Assoon as a team spends the entire day responding to customers, the built-in queues are no longer sufficient. | The Pitfall: The choice of solution depends on the connection model selected. Deciding this after the fact means having to redo part of the project. |
Our Approach
Telephony transitions occur in waves, never all at once.
Four steps, the same for the past fifteen years, no matter where you start: Skype for BusinessCisco, Alcatel, Mitel, Avaya, or a PBX that no one knows how to configure anymore. The first step costs you nothing—it leads to a quote.
01
The audit and the choice of connection
We document what is in place: the central office, service providers, contracts and their expiration dates, the numbering plan, analog phones, DECT phones, rooms, the switchboard, queues, call recording, and applications that dial a number.
Then we calculate the costs of the various connection scenarios, including the exit cost, and tell you which one is viable. This is the most critical decision of the project: it’s based on numbers, not on personal preference.
What We Deliver
- An inventory of existing equipment, including analog and DECT devices
- A comparative analysis of connections over three years, including exit costs
- A Proposed Scope of Work: Scope, Workload, Timeline, Deliverables
02
The Design
Connection architecture, redundancy, revised and streamlined numbering plan, call policies, switchboard and queues redesigned in collaboration with the business, emergency call routing, and what happens when the link goes down.
This is also where the coexistence with the old system will be determined: for several months, the two worlds will have to communicate, transition, and interact with one another.
What We Deliver
- Connection diagrams and redundancy, by operator
- The documented numbering plan, stripped of its workarounds
- Call routes: standard, queues, schedules, overflow, nighttime
- The plan for coexistence with the old power plant, in both directions
03
The Shift, in Waves
First, a pilot site, then waves of users, with the old system kept in place until the new one has proven itself. Phone numbers are portable; they aren’t replaced.
Users are trained before their rollout, not after: that’s what makes the difference between a rollout that’s accepted and one that’s imposed. And the rollback plan is written before the rollout begins.
What We Deliver
- The guide, followed by the wave schedule, by department or by location
- Number portability managed in collaboration with the carrier
- The process: internal calls, external calls, emergencies, transfers, queues, terminals
- Training for users and administrators before each wave
04
Exploitation and Autonomy
After the transition, everyday life begins: arrivals, departures, department changes, new locations, and queues that need to be managed. This workload lasts for years, and it’s what really takes its toll.
Our goal is for you not to need us for that. We equip your teams, and we reserve second- and third-level support for what truly warrants it: a call that gets lost for no apparent reason.
What We Deliver
- A service contract: scope, hours covered, response times
- Monitoring Connections and Call Quality
- Operational tools that let your teams manage numbers and users without us
- The documentation, kept up to date and submitted, including the numbering plan
Preparing the proposal is free of charge. The detailed audit, connection diagrams, and numbering plan are all part of the scope of work: this is engineering work, not a sales brochure.
Our tool, born out of a real problem
NexTeams365 : The telephone service Teams, without PowerShell.
We’re not just system integrators in this area—we’re software developers. That’s because a client showed us what happens to native administration as the system grows: manual “ PowerShell ,” numbering plans in spreadsheet files, and one person who becomes the sole point of contact.
We developed NexTeams365 for a nongovernmental organization with tens of thousands of users spread across more than 280 sites, whose telephony environment had outgrown what standard tools could handle.
The idea is simple: make day-to-day operations accessible to the people who need to do them. Assign a number, move a user, open a site, adjust a queue— without using the command line and without going through us.
That also explains our stance on connectivity: when you’re developing software that uses a telecommunications network, you see very clearly the cost of being dependent on a carrier.
What the platform supports
- Numbers The dynamic numbering plan No more spreadsheet files: numbers, their assignments, and their history are all stored in one place and kept up to date.
- Users Self-Service Assignment and Transfer Common tasks are delegated, with permissions set by site or entity, and a record of who did what.
- Websites Opening a Site Without a Project Rules, policies, and numbers are set according to a template, rather than being re-entered manually each time a site is created.
- Control Consistency and Verification Discrepancies between what is planned and what is actually configured are visible, rather than being discovered by a user.
When does it become worthwhile? If you have fewer than a few hundred users on a single site, the built-in tools are sufficient, and we’ll let you know. Beyond that, or as soon as the number of sites increases, the operational overhead becomes the true cost of the system.
Let's talk about your phone service
What is your situation?
Six reasons to open this file. If any of them sound familiar, you've come to the right place—and we've seen this happen before.
Your control panel is reaching the end of its service life
Alcatel, Cisco, Mitel, Avaya, or Skype for Business : the equipment is getting old, skilled technicians are hard to find, and the service provider raises its prices every year.
Your service provider contract is about to expire
Now is the right time to take control: the connection structure needs to be decided now, not in three years when it will have to be renegotiated.
You're paying for two systems at the same time
Teams For meetings, the old switchboard for calls. Two phone directories, two bills, two reports—and users who no longer know which one to use.
You have both analog and DECT
Elevators, intercoms, alarms, warehouse or hospital communication systems: this is the issue that holds up most projects, and it’s the one we handle best.
Your Teams Phone deployment is stalling
It was launched in-house or by a general-purpose integrator, and it’s running into issues with emergency services, call quality, or numbering. We also take on projects that are already underway.
Work takes up all your days
Every arrival, every departure, and every new site goes through a single person and PowerShell. That is exactly the problem we wrote NexTeams365 to address.
Why Choose Us
Telecommunications is our core business—not just another item in our catalog.
Office Communications Server, Lync, Skype for Business, Teams : We’ve implemented each of these generations and migrated from previous versions to the next. We’re also familiar with what came before —Alcatel, Cisco, Mitel, and Avaya PBX systems—because that’s where projects often begin.
We put ourselves in the customer’s shoes. Whether it’s choosing a service provider or a connection, our advice is designed to give you freedom—even if it means we sell less.
8 000
Users migrated to Teams from Skype for Business and Cisco — 62 offices, 39 countries
280 sites
and tens of thousands of users who are being exploited through the platform we developed
From OCS
Four generations of the same stack, deployed, migrated, and operated
What's included
- End-to-end voice: operator, session controllers, dialing, emergencies, analog, DECT, rooms.
- The contact center as well: Luware, Dynamics 365 Contact Center, AudioCodes Voca, Anywhere365.
- Our proprietary operations platform, designed for a network of more than 280 sites.
- On-site teams: Renens, Sion, Châtel-Saint-Denis. No one opens a support ticket from the other side of the world.
- Federal authorization for staffing services since 2018: We can also assign an engineer to your company.
Frequently Asked Questions
What we're asked to do before we begin.
The six questions that come up on every first date. The answers are intentionally specific: a vague answer at this stage doesn't help anyone.
Should we choose a certified service provider or keep our own session controllers?
It depends on two things: the size of your network and what else you need to connect. If you have analog systems, DECT, an older PBX that needs to coexist with the new system, or a contact center, keep your controllers: they’re what make all of this possible, and they let you switch providers without having to redo the entire project.
If your environment is simple and you don’t have a team to manage this layer, a certified operator can be up and running in a few days and is less expensive to maintain. We also recommend this option when applicable.
What will become of our elevators, doormen, and cordless phones?
They remain, provided that a session controller has been set up to handle them. This is, in fact, one of the main reasons for this architectural choice: these devices do not support Teams and never will Teams.
They figure things out as they go at the start of the project, by walking through the buildings—a license inventory doesn’t capture that. That’s also what distinguishes a telecommunications project from a Microsoft 365.
Can we keep our phone numbers?
Yes: phone numbers are ported. The process is managed in collaboration with the carrier and requires planning—this is often the factor that determines the switchover date, more so than technical considerations.
Number portability is handled in batches, in the same order as the waves of users, so that a service never ends up with half of its numbers on one side and the other half on the other.
What happens if the website's internet connection goes down?
Without taking precautions, your phone service goes down with it: that’s the cost of a service in the cloud, and you need to make that clear before signing the contract, rather than after the first outage.
This can be addressed during the design phase: a backup device on-site that takes over incoming and outgoing calls, a secondary connection, or backup service from another carrier. The choice depends on how much an hour without a phone costs you, and that’s a question we ask early on.
What about emergency calls?
This is the most critical aspect of the project—and the one most often overlooked. A phone in Teams is no longer connected to a wall jack: the routing and location of the caller must be designed on a site-by-site basis and then tested.
We run this test as part of our standard procedure, document it, and repeat it every time a site opens. This isn’t just a bureaucratic formality—it’s what matters on the day someone dials 144.
Will our teams be able to handle the phone calls without us?
That’s the goal. Native administration is sufficient for a simple infrastructure; beyond that, it requires a “ PowerShell ” and becomes the sole responsibility of a single person—which is a risk in itself.
That’s why we wrote NexTeams365 : common actions—assigning a number, moving a user, opening a site—can be delegated, with permissions and a log. We reserve the second and third levels for what truly warrants them.
All About Telephony
That's what a " Teams Phone" project always gets right.
Telephony isn't just about phone numbers. Here are the pages that build on that concept—and through which most of our projects pass.
Let's talk about it
Tell us what’s going well today, and what’s holding you back.
We’ll prepare a quote for free—covering scope, workload, timeline, and deliverables—with no obligation on your part. And if you tell us when your current service provider’s contract expires, we’ll let you know how much it will cost to switch—before you sign the next one.