Choosing the Right Microsoft Teams Phone System Solution

More businesses are adopting Microsoft Teams as a complete enterprise telephony solution, but many organizations are unaware of their options for connecting Microsoft Phone System to the public telephone network (PSTN).

This decision is crucial, as it impacts key factors such as cost, geographic reach, deployment, and support.

In this article, we compare two of the primary options available—Microsoft Calling Plans and Direct Routing—to help you determine which solution best suits your business needs.

Microsoft Teams: The Leading UCaaS Platform

Microsoft Teams has become a leader in Unified Communications as a Service (UCaaS), thanks to:

• Its seamless integration with Microsoft 365

• Advanced collaboration tools – messaging, file sharing, video conferencing

• Built-in enterprise telephony with Microsoft Teams Phone System

More companies are now replacing traditional Private Branch Exchange (PBX) phone systems with Microsoft Teams Phone System, benefiting from a unified, cloud-based communication platform.

However, to connect Teams Phone to the PSTN, businesses must choose the right call routing solution.

What Is Microsoft Teams Phone System & How Does It Work?

Traditional enterprise phone systems route outgoing calls through a PBX to the Public Switched Telephone Network (PSTN) before reaching their destination.

With Microsoft Teams Phone System, this function is handled by a cloud-based PBX hosted by Microsoft, allowing users to make and receive external calls directly from Teams.

However, businesses must choose how to connect Teams Phone to the PSTN, with three main options available:

Direct Routing

• Calls are routed through a third-party provider using their own network infrastructure.

• Provides customized pricing and deployment based on business needs.

Microsoft Calling Plans

• Microsoft handles call routing via its infrastructure.

• Users get a fixed monthly plan with pre-allocated calling minutes.

Operator Connect

• A telecom provider integrates its network directly with Microsoft Teams.

• Offers Microsoft’s simplicity + a provider’s expanded global coverage.

In this article, we focus on the key differences between Direct Routing and Calling Plans to help businesses make an informed decision.

Microsoft Teams Direct Routing vs Calling Plans: Key Differences

While Teams Phone functionality remains the same for both options, there are significant differences in cost, coverage, flexibility, integrations, and support.

Microsoft Teams Calling Plans: A Simple Solution for Small Businesses

Calling Plans are an out-of-the-box solution provided directly by Microsoft. They are easy to deploy, but they come with higher costs, limited flexibility, and geographic restrictions.

Best suited for: Small businesses with fewer than 20 users and limited international calling needs.

Deployment

• Microsoft provides a direct connection between Teams Phone and PSTN.

• Each user gets a dedicated phone number with a fixed calling package.

• Businesses can choose between:

  • Domestic Calling Plans (international calls cost extra).

  • Domestic & International Calling Plans.

Coverage

• Limited to select countries in Europe, North America, Australia, and Japan (33 countries as of writing).

Support & Service

• Microsoft does not offer migration or implementation support.

• Businesses must manage the entire deployment process themselves.

Ideal for small teams that need a quick and simple telephony solution without complex integrations.

Microsoft Teams Direct Routing: The Enterprise-Grade Solution

Direct Routing is the more advanced option, offering greater flexibility, wider geographic coverage, and cost efficiency.

Best suited for: Medium-to-large businesses with 30+ users, global operations, or specific integration needs.

Cost Flexibility

Freedom to choose your telecom provider, ensuring:

• Lower costs per user than Microsoft Calling Plans.

• Negotiable pricing based on your business requirements.

• Customized call packages for different teams or departments.

Deployment

• Direct Routing connects Teams Phone to PSTN via a third-party provider.

• Can be self-managed or hosted by a managed services provider (MSP) for end-to-end support.

• Requires a Session Border Controller (SBC), which can be:

• Physical or virtual (depending on business needs).

• Multi-tenant or dedicated SBC, managed by a Direct Routing as a Service (DRaaS) provider.

Global Coverage

• Direct Routing works in nearly any country worldwide.

• In regions with strict cloud telephony regulations, providers can deploy local SBCs to ensure compliance.

Support & Service

• Managed service providers offer full migration, implementation, and ongoing support.

• Includes SBC setup and maintenance, ensuring a secure and seamless connection between Teams and PSTN.

Ideal for larger businesses that require customizable, cost-effective, and scalable telephony solutions.

Conclusion: Which Option Is Best for Your Business?

Migrating to Microsoft Teams Phone System eliminates the need for legacy on-premise PBX systems, unifying all business communications in the cloud.

However, choosing between Microsoft Calling Plans and Direct Routing depends on:

For small businesses needing a quick, simple solution → Microsoft Calling Plans are an easy option.

For larger companies needing flexibility, global reach, and cost savings → Direct Routing is the best choice.

Why Choose Astroline for Microsoft Teams Direct Routing?

At Astroline, we specialize in Direct Routing solutions for Microsoft Teams.

• Customized solutions tailored to your business needs

• Global coverage with regulatory compliance

• End-to-end migration, SBC setup & support

• Scalable, cost-effective pricing plans

Ready to move your business telephony to Microsoft Teams? Contact us today to get started!