Top 65 MS-721 Interview Question and Answer

Preparing for a Collaboration Communications Systems Engineer (MS-721) interview can be challenging, especially with Microsoft constantly evolving its communication and voice technologies. Whether you’re applying for a new role or aiming to validate your skills with the MS-721 certification, having the right set of questions at your fingertips can make all the difference.

In this blog, we’ve compiled the top 65 most relevant and updated interview questions and answers that cover everything from Microsoft Teams architecture and Direct Routing to advanced voice configurations and real-world troubleshooting scenarios. This guide is tailored to help you walk into your interview with confidence and clarity.

What is the Microsoft MS-721 Exam?

Imagine being the go-to person who makes sure everyone in a company can talk, meet, and work together—whether they’re in the same building or across the world. That’s exactly what a Collaboration Communications Systems Engineer does. And the MS-721 exam is your ticket to proving you’re ready for that role.

This Microsoft certification tests your knowledge of Microsoft Teams, especially its voice, video, and meeting features. But it’s not just about clicking buttons. It’s about understanding how to set up calling systems, connect phone lines using Direct Routing, make meetings secure, troubleshoot audio issues, and even work with other IT teams to make sure everything runs smoothly.

If you enjoy working with modern communication tools and love solving real-world tech problems, this certification can really help you stand out. It’s like having an official stamp from Microsoft that says, “Yes, this person knows how to keep a modern workplace talking.”

Exam	Details
Duration	2 hours
Question Type	Multiple choice, multiple-select, drag-and-drop, case studies
Total Questions	Approximately 40–60 questions
Passing Score	Around 70–75%
Delivery	Online (via Pearson VUE) or at a certified test center
Languages	English
Cost	$165 USD (may vary slightly by region)
Certification	Microsoft Certified: Collaboration Communications Systems Engineer Associate

Role of a MS-721 Collaboration Communications Systems Engineer

A Collaboration Communications Systems Engineer plays a vital role in how organisations stay connected, whether through voice calls, video meetings, or instant messaging. They don’t just make tools like Microsoft Teams work—they design, implement, and secure the entire communication ecosystem behind the scenes. From configuring call flows to troubleshooting voice quality issues, their job is all about ensuring smooth, reliable communication experiences for users across departments and devices.

Here’s a quick breakdown of what this role typically involves:

Aspect	Details
Daily Responsibilities	– Design and manage Teams voice solutions – Configure Direct Routing – Troubleshoot call quality and connectivity issues – Manage call queues and auto attendants – Monitor call analytics and usage reports
Key Tools & Technologies	– Microsoft Teams – PowerShell – Teams Admin Center – PSTN (Public Switched Telephone Network) – SBCs (Session Border Controllers) – Microsoft 365 Defender – Call Quality Dashboard (CQD)
Expected Skills	– Deep understanding of VoIP and telephony systems – Familiarity with networking concepts – Microsoft 365 and Azure AD knowledge – Scripting with PowerShell – Strong troubleshooting and communication skills

Let us now move to the interview questions

Basic Level Questions

These questions focus on testing your fundamental understanding of MS-721 – Microsoft Teams, voice, and collaboration systems.

1. What is Microsoft Teams?
   Microsoft Teams is a collaboration platform from Microsoft 365 that combines chat, video calls, file sharing, and app integrations. It helps teams work together in real-time from anywhere.
2. What is Direct Routing in Microsoft Teams?
   Direct Routing allows businesses to connect their own telephone systems (via a Session Border Controller or SBC) to Microsoft Teams so users can make and receive calls through the public telephone network (PSTN).
3. What are the main components of Microsoft Teams architecture?
   Key components include the Teams client (desktop, mobile, or web), Microsoft 365 services (like Exchange and SharePoint), Teams services (for meetings, chat, calling), and voice integration through Calling Plans or Direct Routing.
4. What is the Microsoft Teams Phone System?
   It’s a cloud-based phone system built into Teams that lets users make, receive, and transfer calls. It replaces traditional PBX systems and supports features like voicemail, auto attendants, and call queues.
5. What is a Session Border Controller (SBC)?
   An SBC is a device or software that securely connects your phone system to Microsoft Teams in Direct Routing. It controls call signalling and media flow between different networks.
6. What is the difference between Calling Plan and Direct Routing in Teams?
   Calling Plan is Microsoft’s ready-to-use PSTN service. Direct Routing lets you use your own telecom provider and infrastructure. Direct Routing is more flexible and often more cost-effective for large organisations.
7. What is PSTN, and how does it relate to Teams?
   PSTN (Public Switched Telephone Network) is the traditional phone network. In Teams, PSTN integration allows users to make and receive regular phone calls through Teams using either Calling Plan or Direct Routing.
8. What are Auto Attendants in Teams?
   Auto Attendants answer incoming calls automatically and guide callers through menu options using keypress or speech recognition, routing them to the right department or person.
9. What are Call Queues in Teams?
   Call Queues route incoming calls to a group of people, such as a support team. Calls are distributed based on rules like availability or order of arrival.
10. How does Microsoft Teams ensure call quality?
    Teams uses tools like Call Analytics and the Call Quality Dashboard (CQD) to monitor and diagnose call quality. It also adjusts media paths dynamically based on network conditions.
11. What is a Teams-certified headset or device?
    These are devices tested and approved by Microsoft to work seamlessly with Teams. They support call control features and deliver better voice and audio quality.
12. How is Teams integrated with Exchange and SharePoint?
    Teams uses Exchange Online for calendaring and meeting data, and SharePoint/OneDrive for storing and sharing files. This allows seamless collaboration across Microsoft 365.
13. What is PowerShell’s role in managing Teams?
    PowerShell allows admins to automate tasks, configure settings, and manage Teams policies and users through scripts and command-line instructions.
14. Can you use Teams without Microsoft 365?
    Teams is part of Microsoft 365, but there is also a free version with limited features. For enterprise voice features, a Microsoft 365 subscription is required.
15. What is tenant-level configuration in Microsoft Teams?
    It refers to settings and policies applied at the organisation level, such as calling policies, voice routing, and user permissions. These settings affect how Teams behaves across all users in a tenant.

Intermediate Level Questions for MS-721

These questions test your understanding of deployment scenarios, policy configuration, and Teams voice infrastructure in MS-721.

16. How do you configure Direct Routing in Microsoft Teams?
    You need to set up a certified SBC, configure SIP trunks, link the SBC with Microsoft Phone System, and use PowerShell to define voice routing policies, PSTN usages, and dial plans.
17. What is a dial plan in Microsoft Teams?
    A dial plan defines how phone numbers are interpreted and normalized in Teams. It ensures users can dial local, national, or international numbers in a consistent format.
18. What is number normalization?
    Number normalization is the process of converting a user-dialed number into a standard format (like E.164) that can be processed and routed by Teams.
19. How do voice routing policies work in Teams?
    Voice routing policies assign PSTN usages to users. These define which voice routes are available to a user and how outbound calls are routed through Direct Routing.
20. What are PSTN usages?
    PSTN usages are building blocks that link voice policies to voice routes. They control call permission levels (e.g., local, national, international) and routing decisions.
21. What are the key steps to deploy Auto Attendants and Call Queues?
    You create resource accounts, assign phone numbers and licenses, then configure Auto Attendants or Call Queues with call flow logic, business hours, and call routing options.
22. What licenses are required for Teams Phone System?
    You need a Microsoft 365 license (e.g., E1/E3 + Phone System add-on or E5 which includes it), and Calling Plan or Direct Routing to enable PSTN connectivity.
23. How does Teams handle emergency calling (E911)?
    Teams uses dynamic emergency calling by mapping users’ locations to emergency addresses. It can route emergency calls to the correct dispatch center via Direct Routing or Microsoft Calling Plans.
24. How do you troubleshoot poor call quality in Teams?
    Use Call Analytics and the Call Quality Dashboard to analyze individual and global trends, check network conditions, jitter, latency, and endpoint issues.
25. What is Media Bypass in Teams Direct Routing?
    Media Bypass allows audio streams to travel directly between Teams clients and the SBC, reducing network hops and improving voice quality.
26. What is Location-Based Routing (LBR)?
    LBR ensures that PSTN calls comply with local regulations by preventing certain calls (like toll bypass) based on the user’s physical location.
27. How do you migrate from Skype for Business to Teams?
    You assess current infrastructure, run Teams upgrade readiness checks, and use modes like Islands or TeamsOnly to transition users gradually or completely.
28. How do Teams policies impact calling features?
    Calling policies control what users can do—like call forwarding, simultaneous ringing, voicemail, and outbound call permissions. Policies can be applied globally or per-user.
29. How do you assign a phone number to a user in Teams?
    Use the Teams Admin Center or PowerShell to assign a Direct Routing or Calling Plan number to a user. The user must have the appropriate license and a Calling Policy.
30. What is the Teams Admin Center used for?
    It’s a web-based portal for managing Teams settings, users, policies, voice configurations, Auto Attendants, and analytics.
31. How do you manage call analytics for troubleshooting?
    Admins can view detailed session reports per user in Call Analytics, including call logs, network performance, device stats, and problem classification.
32. What is the difference between Teams Admin Center and PowerShell?
    The Admin Center provides a graphical interface, while PowerShell offers more control, automation, and bulk management options for advanced administrators.
33. What are Teams-certified SBCs, and why are they important?
    Certified SBCs have been tested by Microsoft to ensure full compatibility and reliability with Teams Direct Routing. Only certified SBCs are supported in production environments.
34. What is a resource account in Teams?
    A resource account is a special type of account used to link phone numbers to Auto Attendants and Call Queues. These accounts don’t need a mailbox.
35. How do you monitor Teams usage across the organization?
    Use the Teams usage reports in Microsoft 365 Admin Center, Power BI integration, or Graph API to track active users, call volumes, and feature adoption.

Advanced/Expert Level questions for MS-721

These questions test your ability to design, secure, and optimize Teams voice and collaboration infrastructure.

36. How do you secure voice traffic in Microsoft Teams?
    Teams encrypts all signaling and media by default using TLS and SRTP. For Direct Routing, you must ensure the SBC supports secure protocols and configure trusted certificates.
37. What are the common reasons for Teams call failures in Direct Routing, and how do you troubleshoot them?
    Issues may include misconfigured SBCs, incorrect dial plans, expired certificates, firewall blocks, or routing policies. Troubleshooting involves checking call logs, using Call Quality Dashboard, and validating SBC logs.
38. How do you integrate Teams with an existing on-prem PBX system?
    By using Direct Routing and connecting the SBC between the on-prem PBX and Microsoft Phone System. You configure call flows to route calls between both systems.
39. How do you configure failover and redundancy in Teams voice?
    Use multiple SBCs in different geographic regions and create voice routes with priorities. Configure DNS and routing policies to automatically reroute calls if one SBC fails.
40. What’s the difference between Online Voice Routing Policy and Tenant Dial Plan?
    Voice routing policies determine how outbound calls are routed, while tenant dial plans handle number normalization before routing decisions are made.
41. How do you ensure high availability of Teams services?
    While Teams is a cloud service with built-in Microsoft redundancy, you can ensure availability for Direct Routing by using redundant SBCs, diverse PSTN trunks, and geo-distributed failover plans.
42. What are CQD and its uses in Teams troubleshooting?
    Call Quality Dashboard (CQD) is a tool for analyzing call performance trends across the organization. It helps detect patterns like poor network conditions or problematic devices.
43. What metrics should be monitored for voice quality in Teams?
    Jitter, latency, packet loss, round-trip time, Mean Opinion Score (MOS), and device compatibility. Consistent values help ensure clear, reliable voice communication.
44. How does Teams handle media path optimization?
    Teams dynamically selects the most efficient media path—client-to-client, via Transport Relays, or through the SBC. Media Bypass improves quality by skipping the cloud relay.
45. How do you handle compliance recording in Teams?
    Microsoft supports policy-based recording via certified solutions through Graph API. You must assign recording policies to users and connect them to a recording bot.
46. How do you scale Teams telephony for a 10,000+ user enterprise?
    Design a distributed SBC deployment, use automation for license and number assignment, standardize policies, and monitor usage and adoption with analytics tools.
47. What’s the process for setting up a Teams calling plan in a new country?
    Check regional availability, obtain Microsoft numbers or port existing ones, assign Phone System licenses, configure emergency calling, and test PSTN functionality.
48. How can you integrate third-party call analytics tools with Teams?
    Use Microsoft Graph API or Power BI with CQD data exports to feed external tools. Some vendors offer real-time dashboards or deeper analysis.
49. How do you prevent toll fraud in Teams Direct Routing?
    Implement strict voice policies, block international dialing where unnecessary, monitor logs, use LBR, and secure SBCs with firewalls and access controls.
50. What is the role of certificates in Direct Routing?
    TLS certificates are used for secure signaling between Teams and the SBC. The SBC must present a valid, trusted certificate for the connection to be established.
51. How do you plan Teams Phone System for hybrid workers?
    Use cloud voice solutions like Calling Plans or Direct Routing. Deploy dynamic emergency calling and configure different policies based on user location and network type.
52. What is a Teams Calling Policy, and how do you customize it?
    Calling policies define what users can do (e.g., call forwarding, call groups, voicemail). You can create and assign different policies via PowerShell or Admin Center.
53. How can you automate voice configuration for users at scale?
    Use PowerShell scripts to assign licenses, phone numbers, and policies. Combine with Microsoft Graph API or identity provisioning tools for full automation.
54. How do you perform a root cause analysis for intermittent call drops?
    Check call logs in Call Analytics, analyze network paths, SBC logs, and look for patterns like specific ISPs, time of day, or affected user devices.
55. What’s your approach for migrating a multinational company from legacy PBX to Teams?
    Start with a pilot, assess current systems, design global SBC infrastructure, define voice routing and dial plans per region, handle number porting, and train users through phased rollout.

Behavioural & Project Experience questions for MS-721

These questions are less about technical theory and more about how you’ve applied your knowledge in real-world situations.

56. Can you describe a project where you deployed Teams Phone System from scratch?
    Yes. In my previous role, I led the deployment for a 500-user organization. I assessed network readiness, set up Direct Routing with a certified SBC, created dial plans, and trained staff. Post-deployment, I used analytics tools to ensure call quality remained stable.
57. Tell me about a time when you had to troubleshoot a major Teams outage.
    During one incident, users couldn’t make outbound calls. I checked SBC logs, confirmed certificates had expired, renewed them, and restarted services. Meanwhile, I communicated status updates to stakeholders and created a report to prevent future issues.
58. Have you ever worked with vendors for Teams voice projects?
    Yes, I’ve collaborated with telecom providers for SIP trunk provisioning and with certified SBC vendors for configuration and testing. Vendor coordination was critical during the number porting and testing phase.
59. How do you ensure user adoption during a Teams rollout?
    By conducting training sessions, creating user guides, setting up pilot groups for feedback, and providing ongoing support. I also tracked usage stats and addressed pain points early.
60. Describe a time when a Teams voice configuration didn’t go as planned. What did you learn?
    I once missed applying location-based policies, leading to international calls being blocked. I learned the importance of carefully reviewing voice routing dependencies and testing with multiple user scenarios before go-live.
61. How do you stay updated on Microsoft Teams changes and best practices?
    I follow Microsoft Learn, Tech Community blogs, attend monthly webinars, and subscribe to Teams Roadmap updates. I also participate in online forums and user groups.
62. What’s the biggest challenge you’ve faced with Teams voice integration?
    Integrating Teams with a legacy PBX that lacked SIP support was complex. We had to use a gateway and map complex dial plans. It taught me to expect edge cases in enterprise environments.
63. How do you handle resistance from users or IT teams during Teams migration?
    I listen to their concerns, show benefits (e.g., simpler management, better mobility), and involve them early in planning. Phased rollout and support during the transition help build trust.
64. Have you ever created custom PowerShell scripts for Teams voice management?
    Yes, I’ve scripted automated license assignments, number provisioning, and policy application. It saves time and ensures consistency across hundreds of users.
65. How would you approach a multi-site voice deployment with different telecom regulations?
    I would segment regions, deploy local SBCs, apply country-specific dial plans and voice policies, and work with legal/compliance teams to meet regulatory requirements like emergency dialing or number masking.

Must-Know Tools & Platforms

If you’re aiming to become a successful Collaboration Communications Systems Engineer, it’s not just about knowing the theory—you need to be comfortable using the tools that bring it all together. Below is a list of essential platforms and tools you’ll work with in real-world projects, along with some useful integrations that can take your Teams voice solutions to the next level.

Tool / Platform	Purpose / Use Case
PowerShell	Automate Teams user management, policy assignments, voice routing, and troubleshooting
Teams Admin Center	Web-based interface for managing users, policies, phone numbers, and call settings
Call Quality Dashboard (CQD)	Monitor and analyze call performance across the organization
Call Analytics	Drill-down into individual user calls for detailed diagnostics
Microsoft 365 Admin Center	Assign licenses, check health status, manage compliance settings
Session Border Controller (SBC)	Connects Teams to PSTN via Direct Routing and ensures secure call signaling
SIP Gateways	Allow legacy analog phones and devices to connect with Microsoft Teams
Microsoft Graph API	Access Teams data programmatically for custom apps, dashboards, and automation
Third-Party Compliance Tools	Enable call recording, archiving, or supervision (e.g., NICE, Verint, Dubber)
Power BI (with CQD exports)	Create custom visualizations and reports from call data

These tools help engineers design, deploy, monitor, and optimise communication systems in Microsoft Teams—from setup to scaling across thousands of users.

Final Tips for Cracking the Interview

Cracking an MS-721-related interview isn’t just about memorising facts—it’s about showing that you can apply your knowledge in the real world. Here are a few last-minute tips to help you stand out:

• Practice hands-on tasks: Use Microsoft 365 trial accounts or labs to experiment with Teams voice settings, PowerShell commands, and Direct Routing.
• Understand use cases: Interviewers love it when you relate answers to real-world business needs and user experiences.
• Brush up on PowerShell: Even basic scripting knowledge can impress recruiters, especially when tied to automation or policy management.
• Know your metrics: Be familiar with CQD, MOS, jitter, latency, and how to read Call Analytics reports.
• Stay updated: Microsoft Teams evolves fast. Follow the Microsoft 365 Roadmap and Tech Community for the latest updates.
• Be confident with storytelling: Be ready to talk about your past deployments, challenges you’ve faced, and how you solved them.

Expert Corner

The MS-721 Collaboration Communications Systems Engineer role is where technical expertise meets user experience. If you’re preparing for this path, you’re stepping into a space that demands both hands-on technical skills and a deep understanding of how people communicate in modern workplaces.

These 65 interview questions and answers about MS-721 cover everything from the basics to advanced deployment strategies and real-world problem-solving. Use them to assess your readiness, identify your weak areas, and get a sense of what hiring managers are really looking for.

Remember, your goal in the interview isn’t just to answer questions—it’s to show how you think, solve, and communicate. With the right preparation, you’ll walk in not just as a candidate, but as a confident, certified collaboration expert.