A Microsoft Teams phone system provides a way to connect your telecoms services to Microsoft Teams, the power to call people outside of your Microsoft 365 business domain and the flexibility to access your calls from any internet-enabled device. In essence, a Microsoft Teams Phone System makes it easy for businesses to turn Teams into a powerful and flexible phone system by connecting it to a feature-rich resilient SIP platform. A Teams SIP phone requires a Microsoft 365 Business Voice license, this will give you the ability to call externally from your Teams phone desktop. The desktop app will display your business phone number, provide call insights and deliver all the other amazing benefits you’d expect from a business phone system.