What certifications and expertise should your Microsoft Teams partner have?

What certifications and expertise should your Microsoft Teams partner have?

by pbx.lu Editorial on May 11, 2026
⏱ 14 min read · Article · Microsoft Teams

What certifications and expertise should your Microsoft Teams partner have?

"Microsoft Teams partner" is one of the most overloaded labels on the Luxembourg market. Almost any IT reseller, integrator, or Microsoft 365 specialist can put the badge on a slide. Very few of them can run a real Teams Phone project across Luxembourg, Belgium, France, and Germany.
This guide is for buyers. It explains what Microsoft actually recognises, what a credible Teams telephony partner should hold at the engineer level, and what to look for beyond paperwork.
💡 The short version. A credible Teams telephony partner is strong in three layers at once: company recognition from Microsoft, voice-specific engineer certifications held by the people actually on your project, and real telecom operating experience in the geographies that matter to you. A partner with only one or two of these is a partial answer.

Not every Microsoft partner is a telephony partner

A Microsoft 365 partner who deploys Exchange, SharePoint, and basic Teams collaboration is not automatically equipped to run a Teams Phone project. Telephony has its own rules. Numbering, porting, emergency calling, call quality, Session Border Controllers, and operator relationships sit outside the standard Microsoft 365 skillset.
📞 Teams Phone is the Microsoft cloud telephony service that turns Microsoft Teams into a business phone system. To dial outside the organisation, it needs a connection to the public telephone network. That connection comes through one of three models: Microsoft Calling Plans, Operator Connect, or Direct Routing.
Most generic Microsoft 365 partners can quote licences and onboard users. Fewer can design call flows, plan an Operator Connect or Direct Routing rollout, and own the result when calls drop or numbers fail to port. That gap is where Teams Phone projects go wrong.

How Microsoft recognises a Teams partner in practice

Microsoft does not formally license partners. It recognises them through a layered partner programme. Two recognitions matter for Teams telephony.
🏢 Solutions Partner for Modern Work is the broad organisational badge. A partner scores at least 70 out of 100 points across three measures: customer success, skilling (the number of certified engineers), and performance (active users grown over a 12-month window). This signals breadth in Microsoft 365 and Teams collaboration. It does not by itself signal voice depth.
📞 Calling for Microsoft Teams specialization is the partner-level voice specialist signal. It requires an active Solutions Partner for Modern Work designation, plus extra evidence: a minimum monthly active user threshold on Teams Phone, at least four engineers who hold both the Teams Administrator Associate certification and the Teams Calling Technical Assessment, and customer references for real Teams Phone delivery.
📌 Why this matters: organisational signal, not personal proof
A specialization is awarded to the company, not to the consultants assigned to your project. A partner can hold Calling for Microsoft Teams and still send you an engineer who has never deployed Direct Routing. The badge tells you the firm has the depth somewhere on the bench. It does not guarantee that depth is on your account. Always ask which named engineers will work on your project, and what they hold.

Which certificate matters most for voice

At the individual engineer level, one Microsoft certification is voice-specific.
🎓 Microsoft 365 Certified: Collaboration Communications Systems Engineer Associate (MS-721) is the voice-specific Microsoft credential. It tests planning, deploying, configuring, maintaining, and troubleshooting Teams Phone, meetings, webinars, town halls, Teams Rooms, and certified devices.
MS-721 is the only Microsoft credential that goes deep on Teams voice. It covers PSTN connectivity model selection (Calling Plans vs Operator Connect vs Direct Routing), licensing, number management, auto attendants and call queues, resource accounts, emergency calling, certified Session Border Controllers, network readiness, and the Call Quality Dashboard. An engineer with MS-721 has at least been examined on the voice surface area, end to end.
Two supporting credentials are useful, but they are not voice certifications in the same sense.
📚 Supporting certifications. Microsoft 365 Certified: Teams Administrator Associate (MS-700) covers Teams administration broadly, including some voice topics but with less depth. Microsoft 365 Certified: Administrator Expert (MS-102) covers Microsoft 365 tenant administration at the expert level, useful for the surrounding identity and licensing work, but not telephony itself.
The right question to ask a partner is not "are you Microsoft certified" but "how many engineers on the project team hold MS-721, and can I have their names." If the answer is vague, treat the rest of the pitch with the same vagueness.
📌 Why these certifications exist at all
Microsoft introduced and maintains voice-specific skilling for a reason. Teams Phone is a real telecom service running on a global cloud. Bad configuration causes real damage: failed emergency calls, broken call queues, poor audio, lost numbers during porting, and security gaps in the SBC layer. The certifications exist to raise the floor of partner skill and reduce buyer risk. They are a useful floor, not a ceiling. Telecom delivery experience matters at least as much.

What a real Teams telephony partner should know

Certifications signal that someone has been tested. They do not by themselves prove operational capability. A credible Teams telephony partner should be able to talk concretely about all of the following.
🛰️ PSTN model selection. When to recommend Calling Plans, Operator Connect, Direct Routing, or a mix. The choice depends on geography, regulation, existing carrier contracts, resilience, and operational appetite.
📜 Licensing and tenant readiness. Which Microsoft 365 and Teams Phone licences are needed for which user types, including resource accounts for auto attendants and call queues. Mistakes here surface as billing surprises.
🔢 Numbering and porting. Acquiring numbers in Luxembourg and neighbouring countries, porting existing numbers without service loss, and handling cross-border ranges. One of the most common failure points in a real-world go-live.
📲 Call flows. Auto attendants, call queues, hunt groups, after-hours handling, and the resource account model behind them. Poorly designed call flows are visible to every caller.
🚨 Emergency calling. Configuring 112 routing, dynamic location handling for users who move between offices, and the regulatory expectations in each country involved.
🛡️ Direct Routing and certified SBCs. Designing the Session Border Controller layer, choosing certified hardware or hosted SBCs, configuring SIP trunks, and operating the trust boundary between the operator network and the Microsoft cloud.
📡 Network readiness and call quality. Bandwidth planning, QoS, and post-deployment troubleshooting using the Teams admin center and Call Quality Dashboard. Voice is unforgiving on weak networks.
🎧 Devices and meeting spaces. Teams-certified phones, common-area phones, headsets, meeting rooms, and the Intune policies that manage them.
🔁 Continuity and survivability. What happens when the internet, the operator, or Teams itself has a problem. Survivable Branch Appliance options, mobile fallback, and clearly documented operational ownership.
🛠️ Post-go-live support. Who answers when something breaks, what the SLA covers, and how escalation to Microsoft and to the operator actually works in practice.

What the Luxembourg market shows publicly

The Luxembourg business telecom market has several active providers. Public evidence of Teams telephony positioning varies between them. We list only what is publicly visible.
🇱🇺 Mixvoip publicly markets Microsoft Teams integration through its own SBC and Direct Routing, with SIP interconnections to the main Luxembourg operators.
🇱🇺 POST Luxembourg publicly markets Direct Routing for Microsoft Teams under the names "MS Teams CloudVoice" and "DirectRouting," letting customers keep Luxembourg numbers and route calls through POST's network.
🇱🇺 cegecom announced in December 2025 the launch of Operator Connect for Microsoft Teams, positioning itself as the first local Luxembourg operator to deliver Operator Connect with Luxembourgish numbering, in collaboration with Microsoft and AudioCodes.
🇱🇺 Proximus NXT Luxembourg (the business arm of Proximus Luxembourg, sister company of Telindus and Tango) publicly markets Microsoft Teams Direct Routing, leveraging its operator and integrator activities.
This is what is publicly visible at the operator level. Public evidence of staff-level credentials, named MS-721-certified engineers, Solutions Partner for Modern Work status, or the Calling for Microsoft Teams specialization is not consistently disclosed on these providers' public pages. That is not unusual in the market. It does mean a buyer cannot rely on the public site alone. The right move is to ask the partner directly, in writing.
⚠️ Public marketing tells you what a provider is willing to claim. It does not tell you what their engineers actually hold. Ask for both.

How Teams data is stored for EU and Luxembourg companies

A common buyer question is "where is my Teams data?" The honest answer is that there is no single location, because there is no single dataset.
Files shared in a Teams chat or channel are typically stored in SharePoint or OneDrive. Chat messages, voicemail, meeting recordings, contact data, and call records are stored in different Microsoft 365 workloads, depending on the content type. Each workload has its own data residency rules.
🇪🇺 February 2025: EU Data Boundary completed. Microsoft's EU Data Boundary now covers Customer Data, pseudonymized personal data, and Professional Services Data for Microsoft 365, Dynamics 365, Power Platform, and most Azure services, stored and processed in datacentres in the EU or EFTA for customers based there. Luxembourg, as an EU country, is in scope.
The realistic picture is more nuanced. Microsoft documents specific scenarios where limited Teams-related data still leaves the EU Data Boundary by design.
⚠️ Documented partial transfers to be aware of. PSTN routing metadata is globally replicated to support call routing to travelling users. Emergency-call temporary numbers are stored in the United States for 60 minutes for callback purposes. Voicemail, auto-attendant, and call-queue greetings are cached in the caller's region for 30 days when reached from outside the EU Data Boundary. Federated chat threads are stored at the location of the user or meeting organiser who initiated them.
For a Luxembourg buyer, the practical question is not "is Teams data in Luxembourg." The better question is: which Microsoft workload stores which content, in which EU or EFTA geography, under which tenant configuration, and which scenarios trigger documented transfers outside that boundary. A serious Teams partner should be able to answer this in writing, with reference to the EU Data Boundary documentation, not from memory.

Is Direct Routing more secure?

It depends. The honest version of this question is whether Direct Routing gives a buyer more control, and whether more control translates into a stronger security posture in the buyer's specific case.
🛡️ Direct Routing: more architectural control. The customer or partner owns the Session Border Controller, which is the trust boundary between Teams and the carrier. Routing policies, recording, encryption, failover paths, and legacy integration are configured on equipment the customer or its partner manages.
🔌 Operator Connect: lower operational complexity. The operator and Microsoft jointly manage the integration. The SBC layer is operator-managed. The customer onboards through the Teams admin center. Fewer moving parts means fewer mistakes.
☁️ Calling Plans: simplest where available. Microsoft acts as the carrier directly. Flexibility is lower. The customer's operational surface is also smallest.
Direct Routing's control has a price. More design choices mean more responsibility. SBC patching, certificate management, capacity planning, monitoring, and incident response sit with the customer or its partner. A poorly operated Direct Routing setup is not more secure than a well-operated Operator Connect deployment. It is less secure.
Operator Connect reduces complexity. For many SMEs in Luxembourg, that lower operational burden is a real security benefit, because fewer moving parts means fewer mistakes.
For organisations with strict policy requirements, complex legacy integration, or a genuine need for explicit control over how voice traffic leaves the tenant, Direct Routing is a legitimate choice. For organisations that want secure, standardised cloud telephony with minimal in-house voice expertise, Operator Connect or Calling Plans are often the safer choice.
📌 The strongest model is the one that matches the buyer's regulatory requirements, resilience needs, legacy estate, and internal operational capacity. Treat "Direct Routing is more secure" as a marketing claim until proven otherwise.

Questions to ask before choosing a Microsoft Teams partner

Use these in a written RFP or in a first meeting. Pay attention to which questions cause hesitation.
❓ The buyer's checklist. 1. Do you hold Solutions Partner for Modern Work? 2. Do you hold the Calling for Microsoft Teams specialization? 3. Which named engineers on our project hold MS-721, and when did they pass? 4. How many Teams Phone deployments have you completed in Luxembourg or with cross-border numbers in BE, DE, or FR? 5. Do you offer Direct Routing, Operator Connect, Calling Plans, or a combination, and which would you recommend for our profile and why? 6. How do you handle number porting from our current operator, and what is the rollback plan if porting fails? 7. How is emergency calling configured for users who move between offices or work from home? 8. Who owns first-line support when call quality drops? Who escalates to Microsoft? Who escalates to the operator? 9. Which Microsoft workloads will store which of our Teams-related data, in which EU or EFTA geography, and which documented scenarios trigger transfers outside the EU Data Boundary? 10. What is the survivability plan if the internet, the operator, or the Microsoft service has an outage?

Red flags

A few practical warning signs. None is fatal on its own. Two or more together are a problem.
🚩 Treat these as warning signs. The partner talks fluently about Microsoft 365 licences and almost nothing about telephony architecture. They cannot clearly explain the commercial and technical differences between Operator Connect and Direct Routing. No voice-certified engineers are named on the project team, only "our team is Microsoft certified." Emergency calling, Call Quality Dashboard, SBC operations, and survivability are not topics they bring up unprompted. Absolute security claims ("Direct Routing is more secure") without any discussion of architecture, operational ownership, or trade-offs. Claims of Luxembourg market expertise that do not survive concrete questions about numbering ranges, porting timelines, or cross-border calling between LU, BE, DE, and FR.

The buyer takeaway

A credible Microsoft Teams partner sits at the intersection of three things: Microsoft recognition at the company level, voice-specific certifications on the engineers actually assigned to the project, and real telecom operating experience in the geographies that matter to the buyer. Any partner strong in one area but weak in the others is a partial answer.
The Luxembourg market has providers active in all of these areas, with different public positioning on Direct Routing and Operator Connect. The right partner for a given business is the one whose strengths line up with that business's regulatory profile, legacy estate, resilience needs, and internal operational capacity. None of that is on a badge. All of it is in the questions a buyer is willing to ask before signing.
🎯 The final test. A Microsoft Teams partner should be able to name the engineers, name the certifications, explain the PSTN model, document the data residency, and own the support boundary in writing, before you sign. If any of those is missing, keep looking.
📚 Part of the Microsoft Teams telephony cluster on pbx.lu. Read next: What Microsoft Teams means for fixed-line business telephony · How Direct Routing Works in Microsoft Teams.
📚 Keep reading on pbx.lu. Compare the Cloud PBX providers active in Luxembourg, read the Microsoft Teams integration feature page, or look up terms in the Cloud PBX glossary.
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