What is Phone System
Phone System is Microsoft's technology for enabling call control and Private Branch Exchange (PBX) capabilities in the Microsoft 365 cloud with Microsoft Teams.
Phone System works with Teams clients and certified devices. Phone System allows you to replace your existing PBX system with a set of features directly delivered from Microsoft 365.
Calls between users in your organization are handled internally within Phone System, and never go to the Public Switched Telephone Network (PSTN)--thereby removing long-distance costs on internal calls.
For making external calls, Phone System provides add-on options for connecting to the PSTN. For more information about voice solutions and PSTN connectivity options, see Plan your Teams voice solution and Connect to the PSTN.
Phone System is available world wide except for Macau.
Phone System features
With Phone System, users can use Teams to place and receive calls, transfer calls, and mute or unmute calls. Phone System users can click a name in their address book, and place Teams calls to that person. To place and receive calls, Phone System users can use their mobile devices, a headset with a laptop or PC, or one of many IP phones that work with Teams.
Phone System administrators can manage calling options and settings from the same console used for messaging, collaboration, and so on.
For more information about Phone System features, see Here's what you get with Phone System.
Connect to the Public Switched Telephone Network (PSTN)
For external calling, Phone System can be connected to the PSTN in one of several ways:
Purchase a Microsoft Calling Plan (domestic or domestic and international). Microsoft Calling Plan is an all-in-the-cloud solution with Microsoft as your PSTN carrier. For more information, see Phone System and Calling Plans.
Use your existing telephony infrastructure for on-premises PSTN connectivity.
You can connect your on-premises telephony infrastructure to Phone System by using Operator Connect Calling or Direct Routing.
For more information about all PSTN Connectivity options, see PSTN connectivity options.
Phone System with services
Phone System can be used for services and voicemail, such as:
Auto attendants - Auto attendants can be used to create a menu system for your organization that lets external and internal callers move through the system to locate and place or transfer calls to company users or departments in your organization. See What are Cloud auto attendants?.
Call queues - Call queue greetings can be used when someone calls in to a phone number for your organization. These greetings include the ability to automatically put the calls on hold and to search for the next available call agent to handle the call. The people on hold can also listen to music while on hold. You can create single or multiple call queues for your organization. See Create a Cloud call queue.
Voicemail - Cloud Voicemail is automatically set up and provisioned for all Teams users. See Set up Cloud Voicemail.