Teams Phone and Calling Basics

Teams Phone is Microsoft's cloud PBX (private branch exchange) offering, licensed as an add-on that gives a user a real telephone number and the ability to place and receive calls to and from the public switched telephone network (PSTN), not just calls between Teams users on the same tenant. It replaces the traditional on-premises PBX hardware and desk-phone wiring that organizations historically maintained, moving call routing, voicemail, auto attendants, and call queues into the cloud alongside the rest of a user's Teams experience, so a single client handles chat, meetings, and phone calls without switching applications.

Organizations connect Teams Phone to the PSTN in one of three ways: Calling Plans, where Microsoft itself acts as the telephony carrier and sells per-minute or unlimited domestic/international bundles directly through the Microsoft 365 admin center; Operator Connect, where a certified third-party carrier is pre-integrated with Teams so the admin selects the carrier and numbers from within the admin center without deploying any on-premises hardware; and Direct Routing, where the organization deploys or leases a certified Session Border Controller (SBC) that bridges Teams to any SIP trunk provider of their choosing, offering the most flexibility (and complexity) for organizations with existing carrier relationships or numbers in countries Microsoft doesn't directly support.

Beyond individual user calling, Teams Phone supports Call Queues, which hold and distribute inbound calls to a group of agents using routing methods like attendant (ring all simultaneously), serial (ring one at a time in order), or round-robin, and Auto Attendants, which present callers with a menu ('Press 1 for Sales, Press 2 for Support') that can route based on time-of-day or holiday schedules configured in the Teams admin center. Both features are configured through Resource Accounts — special Azure AD accounts that don't represent a real person but hold the license and phone number for the queue or auto attendant itself — and voicemail for any user or resource account can be customized per-language, transcribed automatically, and optionally routed to email as an audio attachment with the transcription in the message body.