Microsoft Teams Phone integrates with your existing office infrastructure by extending the Teams platform to handle internal and external calls alongside your current telephony and network setup. Instead of replacing everything at once, it typically sits on top of your existing broadband, local area network (LAN), and, where required, your current phone system or SIP trunks. Users can make and receive calls from their PCs, laptops, mobiles, or certified Teams handsets, while your existing numbers, call flows, and key features such as hunt groups and voicemail can be retained or migrated in a controlled way. This allows you to introduce cloud-based calling at a pace that suits your organisation, without disrupting day-to-day operations.
Integration usually involves connecting Microsoft Teams Phone to the public telephone network through either Microsoft Calling Plans or Direct Routing via a certified Session Border Controller (SBC). With Direct Routing, your existing SIP trunks or on-premise PBX can be linked to Teams, allowing you to keep current contracts, numbers, and call routing rules while adding the flexibility of cloud telephony. Your existing cabling, switches, and WiFi infrastructure continue to carry voice traffic using Quality of Service (QoS) configuration to prioritise calls. This approach reduces the need for separate voice networks, simplifies management, and helps you transition from legacy systems to a modern, scalable communication platform with minimal disruption and clear cost control.
Teams Phone typically integrates by connecting to your existing internet connection and LAN, using your current routers, switches, and structured cabling. Voice traffic runs over the same network as data but can be prioritised using QoS settings, ensuring call quality remains high even during busy periods. Existing office WiFi can also support mobile and laptop-based calling, provided coverage and capacity are sufficient.
If you already have SIP trunks or an on-premise PBX, Direct Routing allows you to bridge these services into Microsoft Teams. A certified SBC manages the connection, enabling you to keep existing numbers, call plans, and many call-handling features while gradually moving users to Teams-based calling. This hybrid approach is particularly useful where you have specialist handsets, analogue lines, or door entry systems that still rely on the legacy PBX.
Handsets and devices can be integrated in stages. Traditional desk phones may be replaced with Teams-certified IP phones, USB headsets, or conference devices, while business mobiles can use the Teams app for unified calling. This staged migration lets you align telephony changes with office moves, contract renewals, or hardware refresh cycles, ensuring continuity and controlled investment.
