6.1 Microsoft Teams and Teams Phone
Key Takeaways
- Microsoft Teams is the Microsoft 365 hub for chat, channels, meetings, files, and calling; channel files live in SharePoint and the Teams calendar is backed by Exchange Online
- Standard channels are open to the whole team, private channels limit membership to a subset of the team, and shared channels let selected people inside or outside the team collaborate without joining the entire team
- Meetings are interactive collaboration; webinars are structured registered events; town halls are large-audience broadcasts — none of these replace Teams Phone
- Teams Phone is the cloud phone system that places and receives Public Switched Telephone Network (PSTN) calls from Teams; meeting audio is not the same capability
- Organizations get PSTN numbers through Calling Plans (Microsoft is the carrier), Operator Connect (a Microsoft-certified operator, no customer Session Border Controller), or Direct Routing (a customer- or partner-managed Session Border Controller)
Quick Answer: Microsoft Teams is the Microsoft 365 app where people chat, meet, share files, and — when Teams Phone is licensed and connected to the Public Switched Telephone Network (PSTN) — place and receive real phone-number calls. Files posted in a channel live in SharePoint. Meetings scheduled in Teams or Outlook share the same Exchange Online calendar. Teams Phone is not “meetings have audio.”
The April 30, 2025 MS-900 outline asks you to describe the collaboration and communication capabilities of Microsoft Teams and Teams Phone. This is a recommend-the-service skill. You will not be asked to size a Session Border Controller or walk through the Teams admin center click path. You will be asked whether a company that wants persistent team workspaces, a company that wants a registered customer briefing, and a company that wants desk-phone replacement are describing the same product feature. They are not.
What Teams is for
Microsoft Teams is the hub that brings conversations, meetings, files, and apps into one place for on-site, remote, and hybrid workers. A team is a collection of people, content, and tools around a project or an ongoing org unit such as Finance or a store location. Teams can be private (invite only) or public inside the tenant (anyone in the organization can join). Each team is backed by a Microsoft 365 group, so membership, a SharePoint team site, and a group mailbox stay in sync.
Work inside a team is organized into channels. Microsoft’s own overview is the scoring key: channels keep conversations organized by topic, project, or discipline, and files you share on the Files tab of a channel are stored in SharePoint.
| Channel type | Who can see it | Typical exam signal |
|---|---|---|
| Standard | Every member of the parent team | Open team workspace; default General channel |
| Private | Only a subset of the parent team | Sensitive workstream that other teammates must not see |
| Shared | Selected people inside or outside the team — they do not have to join the whole team | Cross-team or external partner work on one workstream |
A standard channel is the default. It is visible to the whole team, uses the team’s SharePoint site for files, supports scheduled meetings, Planner tabs, bots, and connectors, and can use channel moderation. A private channel limits membership to a chosen subset of the team. It gets its own dedicated SharePoint site so those files are not sitting in the parent library. A shared channel is the one built for collaboration without adding someone to the entire team. You can share it with people in other teams and, using Microsoft Entra B2B Direct Connect, with external participants. Shared channels also get a dedicated SharePoint site. Guests (the classic guest-access model) can join standard and private channels; shared channels use external participants instead of guests.
Do not over-learn every cell in Microsoft’s channel-feature table. Remember the membership rule and the storage rule: standard = whole team, shared site; private = subset of the team, dedicated site; shared = people who are not on the whole team, dedicated site.
Chat is the other conversation surface. One-to-one and group chats are for ad hoc, persistent threads that are not organized as a team workspace. Chat is the right answer when two people need a quick back-and-forth, or a small group needs a temporary thread that is not a project team. Files shared in a chat typically land in the sharer’s OneDrive for Business, not in the team SharePoint library. That split — channel files in SharePoint, chat files in OneDrive — is the same content map Chapter 5 taught from the SharePoint and OneDrive side.
Meetings, webinars, and town halls
Teams is also the meeting client. A meeting is interactive collaboration: participants can typically share audio, video, and content, use chat, raise a hand, and open a whiteboard. You schedule a meeting from Teams or from Outlook. Those calendars are the same Exchange Online calendar. A meeting you create in Outlook appears on the Teams Calendar app; a Teams meeting invite is an Exchange calendar item. That is why “Teams meetings need a separate calendar product” is a trap.
Microsoft also documents events that are not ordinary meetings:
- Webinars are structured events with registration, presenter and attendee roles, and a more produced experience. Official admin guidance treats interactive events up to the webinar scale as webinar-policy events. Use a webinar when the stem says “register attendees,” “presenters versus attendees,” or “a customer or partner briefing,” not a working session where everyone should talk.
- Town halls are events optimized for large audiences — all-hands, leadership broadcasts, organization-wide announcements. Attendees are largely a viewing audience. Town hall policy settings govern the large-audience path. Use a town hall when the stem says “entire company,” “broadcast,” or “large audience,” not a 12-person project standup.
Classic Teams live events were the earlier large-broadcast product. Microsoft retired live events; webinars and town halls are the current event types you should name. You do not need unpublished attendee SKUs for MS-900. You need the job each type does.
Teams versus email versus Stream
MS-900 likes “which Microsoft 365 service?” stems that mix communication products.
- Email (Exchange Online and Outlook) is asynchronous, addressed, and mailbox-based. Use it for formal notices, external people who are not in your Teams tenant, and anything that must live as a message in a mailbox. Email is not a persistent team workspace and it is not a meeting client.
- Teams is the real-time and near-real-time collaboration surface: chat, channels, meetings, and calling. Use it when people need a conversation, a shared workspace, or a live meeting.
- Microsoft Stream is the enterprise video service for on-demand video content. It is not a phone system and it is not a substitute for channel discussion. Meeting recordings are stored as files in OneDrive (for scheduled/private meetings) or SharePoint (for channel meetings), and they can be watched through Stream experiences. “Put the all-hands recording where people can replay video” can involve Stream; “replace the PBX so users dial +1 numbers from Teams” is Teams Phone.
Teams Phone is PSTN calling
Teams Phone is Microsoft’s cloud phone system (cloud Private Branch Exchange, or PBX). Licensed users make and receive PSTN calls — calls to and from ordinary telephone numbers — from the Teams app on desktop, mobile, certified desk phones, and meeting-room devices. Teams Phone also provides calling features such as voicemail, call forwarding, transfer, hold, auto attendants, and call queues.
A meeting that has microphone audio is not Teams Phone. Anyone in a Teams meeting can talk. Teams Phone is what lets a user dial a customer’s mobile number or publish a company main number that rings a call queue. Official Microsoft guidance is explicit: the user needs a Teams Phone license and a PSTN connectivity option before they can place those external telephone calls.
The PSTN is the global public telephone network. Connecting Teams Phone to the PSTN is how the organization gets phone numbers. Microsoft documents several connectivity models. For MS-900, master the three classic “how do we get numbers?” answers:
| Connectivity option | Who is the carrier? | Who runs the edge? | Exam signal |
|---|---|---|---|
| Microsoft Teams Calling Plans | Microsoft | Microsoft | Simplest, fully Microsoft-managed numbers and minutes |
| Operator Connect | A Microsoft-certified operator | The operator (no customer Session Border Controller) | Keep a preferred carrier; manage users and numbers in the Teams admin center |
| Direct Routing | The operator you choose | A certified Session Border Controller (SBC) that you, a partner, or a Direct-Routing-as-a-Service provider manage | Existing PBX, complex routing, or a carrier that is not in Operator Connect |
Calling Plans are the all-in-the-cloud path. Microsoft supplies phone numbers and calling service. Admins assign a Calling Plan after the user has Teams Phone. Microsoft publishes Domestic, International, and Pay-As-You-Go plan types; do not memorize unpublished minute pools or list prices for this exam.
Operator Connect is for organizations that want a Microsoft-certified landline operator already integrated with Teams. The operator manages PSTN infrastructure. Administrators enable the operator and assign numbers in the Teams admin center. You do not deploy your own SBC. Official Learn language: Operator Connect is a good choice when you want a managed PSTN solution without maintaining Session Border Controllers.
Direct Routing connects Teams Phone to any PSTN operator through a certified SBC. It is the flexible, customer-managed path: keep an existing carrier, integrate analog devices or a leftover PBX, or serve a country where Calling Plans and Operator Connect are not the right fit. Flexibility is the benefit. Owning SBC operations is the cost.
Microsoft also documents Teams Phone Mobile, in which a certified mobile operator assigns the user’s mobile SIM number as the Teams number. Treat it as a related official option for mobile-first workers, not as a replacement for the three classic MS-900 number-acquisition answers.
Organizations can mix connectivity types in one tenant — Calling Plans in one country, Operator Connect in another, Direct Routing for a plant that still has a PBX. The exam wants the best fit for the stated constraint, not a claim that a company may use only one model forever.
Realistic exam-style scenarios
Channel membership. Legal wants a workspace only the legal staff on the broader Corporate team can see. That is a private channel, not a shared channel and not a new email mailbox. If Legal instead needs outside counsel on one matter without adding those lawyers to every Corporate channel, that is a shared channel (external participants), not “just make the standard channel public.”
Files follow the surface. A user uploads a specification to the Engineering team’s General channel. The file is in the team’s SharePoint library. Another user drops a draft in a one-to-one chat. That file is in OneDrive. “Teams stores everything in Stream” is wrong.
Meeting type. Leadership wants an all-hands that thousands of employees will watch. That is a town hall (large-audience event), not a standing project meeting and not Teams Phone. A partner workshop with registration and a small presenter team is a webinar. A weekly project standup where everyone talks is a meeting.
Calendar. A user schedules a Teams meeting from Outlook. It appears on the Teams Calendar because both clients read Exchange Online. You do not recommend a third calendar product.
Voice, not video. A company wants to retire desk phones and let staff dial customer mobile numbers from Teams. That is Teams Phone plus a PSTN option. “They already join Teams meetings, so they already have Teams Phone” is the classic trap.
How they get numbers. A mid-size firm wants Microsoft to be the telephone company — Calling Plans. A global firm wants to keep its certified national carriers and does not want to run SBCs — Operator Connect. A manufacturer must keep an existing PBX and a regional carrier that is not in the Operator Connect directory — Direct Routing.
Exam traps
- Meeting audio is not Teams Phone. PSTN calling requires Teams Phone plus Calling Plans, Operator Connect, or Direct Routing.
- Do not pick Direct Routing just because a third party is involved. Operator Connect is the certified-operator path that does not require a customer SBC.
- Do not pick Calling Plans as the only way to get numbers. Microsoft is one carrier option, not the only one.
- Shared channel ≠ private channel. Private limits a subset of the existing team. Shared brings in people who are not on the whole team.
- Channel files are SharePoint, not Stream and not the mailbox. Stream is video. Exchange is mail and calendar.
- Town hall ≠ webinar ≠ meeting. Broadcast, registered event, and working session are different answers.
Official sources
- Overview of teams and channels — standard, private, and shared channels; files in SharePoint
- PSTN connectivity options — Calling Plans, Operator Connect, Teams Phone Mobile, Direct Routing
- Microsoft Teams Calling Plans — Microsoft as the PSTN operator
- Plan for Operator Connect — certified operator, no customer SBC
- Plan Direct Routing — certified Session Border Controller
- Overview of meetings and events — meetings versus webinar-scale and town-hall-scale events
- Study guide for Exam MS-900 — Teams and Teams Phone skill
A company already holds Microsoft Teams meetings with microphone and camera audio. Leadership now wants employees to dial customers' mobile numbers and publish a main company number that rings a receptionist queue. Which capability is required beyond ordinary meeting audio?
A user uploads a project plan to the Files tab of a standard Teams channel. Where is that file stored?
An organization wants Teams users to keep working with a Microsoft-certified telephone operator, manage numbers in the Teams admin center, and avoid deploying or maintaining its own Session Border Controller. Which PSTN connectivity option matches?
A product team wants outside design-agency staff to work in one persistent Teams workspace without adding those agencies as members of the entire product team. Which channel type is built for that membership model?