Glossary

What is Direct Routing?

Direct Routing is a Microsoft Teams calling option that connects Teams to the public telephone network (PSTN) through a Session Border Controller (SBC) and a carrier of your choice — rather than buying calling plans from Microsoft. It is how an organization gives Teams users real phone numbers and PSTN calling while keeping their preferred telephony provider and rates.

In short: Teams becomes the calling app, but the dial tone comes from your carrier over SIP, connected through an SBC that Microsoft certifies.

How Direct Routing works

Users place and receive calls inside the Microsoft Teams client.
Teams hands PSTN-bound calls to a certified SBC (cloud-hosted or on-premises).
The SBC connects to your carrier over SIP trunks.
The carrier terminates the call to the public phone network.

The SBC is the required piece: it translates between Teams’ signaling and standard SIP, enforces security, and handles failover. Providers offer it as a managed service so you don’t run hardware.

Direct Routing vs. Operator Connect vs. Calling Plans

Microsoft Teams has three ways to get PSTN calling:

Microsoft Calling Plans — buy minutes directly from Microsoft. Simplest, least flexible, often priciest at scale.
Direct Routing — bring your own carrier via an SBC. Maximum control over carrier, rates, numbers, and regions; needs the SBC layer.
Operator Connect — pick a participating carrier from the Teams admin center; the carrier runs the SBC for you. A middle ground: carrier choice without managing infrastructure.

Direct Routing wins when you need a specific carrier, global coverage, existing number portability, or custom call flows. Operator Connect wins when you want carrier choice with near-zero setup.

Why businesses choose Direct Routing

Keep your carrier and rates — bring your own carrier instead of Microsoft’s calling plans.
Global and regional coverage — route numbers in countries Microsoft Calling Plans don’t serve well.
Advanced call flows — integrate contact center, analytics, compliance recording, and AI on the voice path.
Number portability — keep existing numbers across the move to Teams.

Common questions

What is the difference between Direct Routing and Operator Connect?

Both give Microsoft Teams PSTN calling through a third-party carrier. With Direct Routing, you (or your provider) configure and manage the SBC connection — maximum flexibility over carrier, rates, and regions. With Operator Connect, you pick a participating carrier from the Teams admin center and they run the SBC for you — far simpler setup, slightly less flexibility. Direct Routing suits complex or global needs; Operator Connect suits fast, standard deployments.

Do I need an SBC for Direct Routing?

Yes. A certified Session Border Controller is the mandatory component — it connects Teams to your carrier’s SIP trunks, handles signaling translation, security, and failover. You don’t have to own hardware, though: most providers offer the SBC as a fully managed cloud service, so “needing an SBC” in practice means choosing a Direct Routing provider that includes one.

Is Direct Routing cheaper than Microsoft Calling Plans?

Often, at scale. Because you bring your own carrier, you negotiate call rates directly instead of paying Microsoft’s per-user plan pricing — which usually wins for high call volumes, international calling, or large user counts. The trade-off is the SBC layer and setup; a managed Direct Routing provider folds that into the service so the savings still land.

Can I keep my existing phone numbers with Direct Routing?

Yes. Direct Routing supports porting existing numbers to your chosen carrier, so users keep the numbers customers already know when moving to Teams calling. This number portability is a common reason organizations pick Direct Routing over Microsoft Calling Plans.

See DialPhone for Microsoft Teams

Microsoft Teams calling → · SIP trunking → · Pricing →

Operator Connect — the managed-carrier alternative
SBC — the session border controller Direct Routing requires
SIP trunking — the carrier connection underneath
BYOC — bring your own carrier