As Microsoft Teams evolves into a Unified Communications as a Service (UCaaS) hub, modern businesses are increasingly adopting it not just for internal collaboration but also for external calling.
As a UCaaS tool, Teams supports video, chat, audio, and phone calls for internal business collaboration. For external calling, Microsoft offers Calling Plans—a built-in solution that allows Teams users to make and receive calls via PSTN. However, Microsoft Calling Plans have limited global coverage, fewer features, and reduced flexibility for external calling. This can limit global businesses from reliably communicating with their international customers.
This is where Microsoft Teams Direct Routing comes in. Direct Routing brings advanced telephony to Teams by letting businesses bring their preferred carrier to Teams. This enables teams to make and receive external calls directly from their Teams platform, providing businesses with a reliable and flexible path to global communication, voice control, and substantial cost savings.
In this guide, we’ll cover:
- What is Direct Routing for Teams
- How Direct Routing Works
- Direct Routing vs Microsoft Calling Plans
- Benefits of Direct Routing for Teams
- Practical Use Cases
- Adding Global Coverage to Microsoft Teams
What is Direct Routing for Teams?
Instead of relying solely on Microsoft Calling Plans, businesses can bring their own carrier (BYOC) using a certified Session Border Controller (SBC). With Direct Routing, you can expand communication across your existing phone systems, including Microsoft Teams, analog devices, and third-party PBXs.
To fully understand how Direct Routing works, it helps to break down the core technical components involved. These elements work together to enable external PSTN calling within Teams:
1. Microsoft Teams Phone: This is the core voice component in Microsoft 365, enabling call control and PBX capabilities within Teams. It lets users make, receive, and transfer calls directly from the Teams interface.
2. Session Border Controller (SBC): An SBC for Teams is a device or software that securely connects Microsoft Teams to your chosen telephony provider. It acts as a translator and gatekeeper, ensuring that call traffic is routed correctly and protected against threats like DoS attacks or codec mismatches. The SBC is a required element for Direct Routing. Without it, Teams cannot connect to an external voice network.
3. Bring Your Own Carrier (BYOC): This allows you to use a third-party voice carrier—like United World Telecom—instead of Microsoft’s Calling Plans. This approach provides more flexibility, better global coverage, and typically lower costs. Direct Routing is Microsoft’s way of enabling BYOC.
4. SIP Trunk: A SIP trunk is a virtual phone line that transmits voice over IP (VoIP) networks. It connects your SBC to the public telephone network (PSTN) via your voice provider. The SIP trunk is how your business makes and receives calls outside of Teams, using your chosen provider’s global infrastructure.
5. Fully Qualified Domain Name (FQDN) & Trusted Certificate: Each SBC must have an FQDN and a TLS certificate issued by a Microsoft-trusted Certificate Authority. This ensures encrypted, authenticated communication with Microsoft 365.
6. Transport Layer Security (TLS) Encryption: A security protocol that encrypts data to ensure safe and private communication over a network.
How Direct Routing Works?
Direct Routing enables Microsoft Teams to handle both inbound and outbound calls over the PSTN using a third-party carrier. Here’s how each call direction works, and how the underlying components—Teams Phone, SBC, and SIP trunking—operate together:
| Call Flow Direction | Key Elements |
| Outbound | Teams → Phone System → SBC → SIP → PSTN |
| Inbound | PSTN → SIP → SBC → Phone System → Teams |
- Outbound Calls (Teams client → PSTN endpoint):
- A user places a call from their Microsoft Teams client.
- Microsoft Phone System receives and processes the call and applies your preset voice routing policies.
- The call is securely routed over TLS-encrypted SIP to the SBC using the registered FQDN.
- The SBC may apply outbound rules (e.g., number formatting), then pass the call to your selected carrier via a SIP trunk.
- The call is completed through the PSTN to the destination number.
- Inbound Calls (PSTN endpoint → Teams client):
- A call arrives from the PSTN to one of your organization’s business numbers.
- The call is delivered through your telecom provider’s SIP trunk to your SBC.
- The SBC applies inbound translation rules (e.g., adding a “+” or country code) and forwards the request securely to Microsoft Phone System.
- Based on the number and routing configuration, Microsoft Teams delivers the call to the correct user or application, as set up.
By controlling how calls are routed in and out of MS Teams, this voice architecture gives businesses full flexibility to:
- Choose their preferred global carrier (BYOC)
- Apply customized routing rules (e.g., time of day, region)
- Optimize call quality and cost
- Maintain secure, compliant communication.
Why Use Direct Routing Instead of Microsoft Calling Plans?
So, if Microsoft Teams has its own Calling Plans, what is the purpose of Direct Routing?
One of the primary ways to connect Microsoft Teams to the PSTN is through Microsoft’s built-in, cloud-based Calling Plans. In this setup, Microsoft acts as your PSTN carrier, handling all internal and external voice traffic. With this setup, costs depend on Domestic or International Calling Plans, which can escalate based on call volume and global reach.
Unfortunately, these plans are only available in select countries and may not offer the global reach that international organizations require. For companies with global ambitions, this lack of unified coverage can be a significant roadblock to seamless communication.
To scale globally in a cost-effective manner, Direct Routing becomes a strategic move. By using Direct Routing with a provider like United World Telecom, businesses:
- Scale their voice infrastructure quickly and efficiently across regions without being restricted by Microsoft’s limited Calling Plan availability.
- Quickly obtain and activate international phone numbers from more than 160 countries. Check out our country coverage.
- Get 24/7 responsive support and customization options for your customer calls, advantages you won’t find with Microsoft’s native plans.
Benefits of Direct Routing for Microsoft Teams
The majority of digital transformation projects aim to standardize and integrate IT software, particularly in areas such as CRM and ERP, yet telephony is often neglected. In reality, many businesses still rely on mismatched PBX systems across global offices.
Switching to Microsoft Teams Direct Routing helps unify communications in the following ways:
• Global Coverage
Direct Routing connects your Microsoft Teams environment to a vast worldwide voice network, enabling your organization to secure various types of numbers–local, toll-free, non-geographic, and mobile numbers.
• Unified Communication Platform
By integrating Direct Routing, you unify voice, video, chat, and collaboration in Teams, simplifying communication and reducing dependency on numerous tools.
• Smooth External Communication
With Direct Routing and global coverage, users can make and receive international calls seamlessly within Teams, connecting reliably with clients, partners, and vendors outside the platform.
• Security with Microsoft-Certified SBCs
A pre-configured, Microsoft-Certified SBC ensures encrypted SIP communication via TLS and trusted certificates. This gives your business a robust, carrier-redundant network for reliable global voice services.
• Improved Productivity and Workflow
MS Teams users can manage calls, view history, and access advanced features in one platform, helping remote and hybrid teams stay organized, respond faster, and collaborate seamlessly without toggling between tools.
• Cost-Efficiency
Direct Routing offers greater control over telecom spending. You also gain flexibility to choose your preferred carrier and optimize rates in less expensive ones.
• Enhanced Local Presence with Outbound Caller ID
Direct Routing solutions allow you to manage outbound caller ID, which helps improve answer rates in key markets, thereby establishing a more substantial local presence for your businesses.
• Advanced Call Features
When you bring your own carrier to Teams, your telephony provider can offer more than basic calling services. You can access features like IVR, call recording, AI Call Insights, advanced call routing, and detailed analytics, enhancing overall call management.
How to Use Direct Routing for Global Business Communication
When Microsoft Teams and Direct Routing integrate, the platform becomes a fully functioning business phone system. This configuration enhances global reach, handles complex telephony requirements, and opens enhanced voice capabilities. Below are a few use cases on how businesses can take advantage of this telephony integration:
1. International Companies with Offices in Multiple Countries
International businesses can use local numbers for each country or region while streamlining voice communication across boundaries.
An example:
Say a multinational IT firm has its headquarters in India with branches in Singapore, London, and New York. Using Direct Routing for Teams and international numbers with local prefixes, employees can make and receive external calls from anywhere, connecting locally in each country. Thereby simplifying their international communication system.
2. Remote and Hybrid Workforces
Support your distributed teams working remotely, in-office, or across time zones with reliable voice internal and external communication through Teams and cloud telephony.
An example:
A fully remote tech startup has developers based across North America and the Middle East. With Direct Routing for Teams, every team member can make and receive business calls using the Teams app on their laptop or smartphone—no matter where they are. Managers can send incoming calls from North & South America time zones to the North American team and calls from MENA customers to the Middle East team. This ensures seamless internal and external communication without relying on physical phone systems.
3. Companies Consolidating PBX Infrastructure
Managing multiple phone systems and carriers often leads to complex licensing, inconsistent service levels, and high overhead maintenance. By integrating your telephony directly into Microsoft Teams with a single, trusted carrier that offers extensive global coverage, you can eliminate the need for multiple vendor contracts, redundant infrastructure, and ongoing system maintenance. This not only reduces administrative burden and operational costs but also ensures a reliable calling experience across your entire organization.
An example:
A large manufacturing company with PBX or phone systems in its different locations across the country can decide to consolidate. By implementing Direct Routing and migrating all communication to Teams, they reduce their telecom maintenance contracts.
4. Enterprises Migrating from Legacy PBX Systems
Moving away from outdated PBX hardware doesn’t have to interrupt your business. With MS Teams Direct Routing, the transition to a cloud-based phone system is designed to be gradual and non-disruptive. Organizations can run both systems in parallel during migration, allowing teams to adapt at their own pace. Number porting, call routing, and user provisioning are managed behind the scenes by your Direct Routing and telephony provider, minimizing downtime and IT workload. The result is a seamless, secure transition to Microsoft Teams calling with minimal impact on day-to-day operations.
An example:
A financial institution currently running an aging on-premises PBX can choose Direct Routing as part of its digital transformation initiative. Over several months, they progressively move departments to Teams Voice, ensuring business continuity while transitioning to a cloud-based communication system.
5. Teams with High Outbound International Calling Volume
Organizations with high call volumes can significantly reduce costs and manage outbound calling processes using Direct Routing. By routing calls through an SBC and a telecom provider with competitive international rates and local caller ID capabilities, businesses avoid high per-minute charges while making local calls.
An example:
An export-import company that frequently contacts suppliers across East Asia, Europe, and North America can switch from standard calling plans to Direct Routing. And with a global telephony provider, they can make outbound calls using local phone numbers and caller IDs for target countries. As a result, it significantly reduced its monthly international call expenses while ensuring optimal call pick-up rates.
6. Contact Centers Using Teams as Their Primary Communication Hub
Contact centers depend on fast, reliable communication and effective workflows. Managers and agents can access enterprise-grade features, like call routing, call recording, and advanced analytics, right within the Teams interface by integrating Direct Routing. This eliminates the need for separate telephony platforms, improving operations and supporting performance.
An example:
A global tech support contact center can use Teams for internal collaboration while handling all customer calls through Direct Routing. Managers may track conversations, receive inbound calls, route them automatically depending on language, and view recordings or performance data.
7. Global and Regional Customer Support Teams
Direct Routing empowers global and regional support teams to deliver more personalized, trustworthy service by using local phone numbers for inbound calls and displaying local caller IDs when reaching out to customers for follow-ups. This localized presence not only enhances brand credibility but also significantly boosts call connection rates, especially in regions where customers are more likely to engage with familiar local numbers.
An example:
A Latin American support team can use local phone numbers from different Latin American countries to forward and receive incoming calls in their Colombia service center.
8. International and Regional Sales Teams
Direct Routing empowers international and regional sales teams to improve outreach by using local caller IDs when prospecting—an essential tactic for building trust, increasing answer rates, and establishing a stronger presence in target markets.
An example:
A company with its EMEA sales team based in the UK or an APAC team operating out of Singapore can assign local numbers for nearby regions. This allows them to contact prospects in countries like Germany, France, or Japan while appearing as a local business. As a result, sales reps overcome caller hesitation, boost engagement, and build strong client relationships without needing a physical office in those countries.
9. Businesses Entering New Markets
International phone numbers paired with Direct Routing provide an efficient and economical way for companies entering new markets to set up a local phone presence without having to invest in physical infrastructure. This helps businesses stay in regulatory compliance and establish confidence with local clients.
An example:
An e-commerce company has decided to expand its operations into Germany. Instead of setting up a physical office, they can integrate a German local phone number within their Teams environment. Their sales and support teams can now manage calls that come from Germany.
Adding Global Coverage to Your Microsoft Teams Environment
Enhance your Microsoft Teams setup with global voice capabilities by integrating with United World Telecom.
With Teams Direct Routing from United World Telecom, we assist you in growing your Teams environment by enabling PSTN connectivity and global coverage across more than 160 countries. Our platform ensures seamless integration and reliable calls, regardless of whether you need local, toll-free, or mobile numbers.
As a global telephony provider for Teams, we help companies use a single, cloud-first platform to unify voice across geographical boundaries. With our user-friendly telephony control panel, you can manage numbers, features, routing rules, and user settings all in one place. Our SBCs, certified by Microsoft, guarantee enterprise-level security.
We don’t just provide the tech—we support you every step of the way. From setup and SIP trunk provisioning to configuration and testing, our team offers hands-on guidance and 24/7 support. With our certified SBC and global voice platform, you can connect your Microsoft Teams users across international borders.
Start building a more flexible and secure Teams Direct Routing voice solution today. Want to learn more about our solution and how to get started? Talk to our experts now — call us or chat with us!