Direct Routing is the correct solution for integrating an existing SIP trunk provider with Teams Phone. It allows you to use your existing telephony infrastructure and carrier contracts while moving users to Teams, enabling a seamless migration of their existing phone numbers without requiring a full number port to a Microsoft Calling Plan immediately.

For a problem isolated to a single physical device, the most efficient first step is to inspect the device’s specific settings. The configuration profile dictates its behavior and policies, and a failed or pending firmware update is a common cause for a device to become unresponsive or show service errors, which can be remedied directly from the admin center.

For accurate emergency calling with Direct Routing, you must define the physical network topology (Trusted IPs/Network Sites) and pair it with specific location data. The Location Information Service (LIS) maps network elements (like subnets or wireless access points) to a validated civic Emergency Address. This combination ensures calls from that location are routed to the appropriate local PSAP with the correct address information.

A single Auto Attendant can handle this requirement elegantly. You configure the attendant’s operating hours (e.g., 9 AM to 5 PM). During these defined business hours, incoming calls follow one call flow (e.g., direct to a call queue or user). Outside those hours, calls automatically follow a different, pre-configured after-hours call flow (e.g., a menu with the specified options). This is automated and requires no daily manual intervention.

Jitter is the variation in latency (delay) between packets arriving. Excessive jitter means voice packets do not arrive at a consistent interval. The jitter buffer tries to compensate, but if the variation is too high, packets may be discarded if they arrive too late to be played in sequence, causing audible glitches, gaps, or robotic-sounding speech.

Communication Compliance policies in the Microsoft Purview compliance portal are designed for this exact scenario. You can create a policy that scopes to the finance department users and defines conditions to capture only external communications (e.g., where participants are outside the organization) while excluding internal ones, ensuring adherence to the regulatory requirement.

A consistent echo of one’s own voice is typically acoustic echo. This happens when sound from the speaker (e.g., a laptop speaker, headset speaker, or room speakerphone) leaks back into the microphone on the same device. This is a local audio hardware/configuration issue, not a network problem. Solutions include using a better headset, lowering speaker volume, or enabling echo cancellation features.

A Call Queue is designed for this exact purpose. You assign the shared phone number to the queue, add the five team members as agents, and set the routing method to ‘Attendant routing’ (simultaneous ring). You then configure the timeout setting (e.g., 20 seconds) and specify where unanswered calls go, such as a shared voicemail-enabled resource account.

The SBC is a critical network element in Direct Routing. It serves as a secure gateway between your existing telephony carrier (using standard SIP protocols) and the Microsoft Phone System. Its core functions include protocol interconnection, security (firewall traversal), and often media traffic handling, enabling the seamless flow of calls between the PSTN/carrier network and Teams users.

Direct Routing is the correct solution for integrating an existing SIP trunk provider with Teams Phone. It allows you to use your existing telephony infrastructure and carrier contracts while moving users to Teams, enabling a seamless migration of their existing phone numbers without requiring a full number port to a Microsoft Calling Plan immediately.0