(Editor's Note: This post was written for 8x8 by Metrigy President and Principal Analyst Irwin Lazar.)

Today, more than 70% of companies use Microsoft Teams for meetings and chat according to Metrigy’s Workplace Collaboration: 2023-24 global research study of 440 organizations. Additionally, 36.9% of those using Microsoft 365 who have not yet adopted Teams Phone System, plan to do so in the next 12-24 months. As IT and business leaders evaluate how best to integrate calling into Microsoft Teams, most consider either using Microsoft Teams Phone System to provide a native calling experience within the Teams app or using a Teams add-on to integrate a cloud-based calling platform with Teams. Those choosing the former must then choose how to connect Microsoft Teams Phone System to the PSTN, with options including Direct Routing, Operator Connect, and Microsoft’s own Calling Plan.

Considering the first decision: Teams Phone System or a third-party calling provider; buyers should weigh a variety of factors including:

  • Feature requirements - Third-party calling platforms, especially those that are cloud-based, may offer a larger variety of capabilities including support for legacy endpoints as well as call recording for regulatory compliance
  • Reliability - Microsoft Teams only offers 99.99% availability whereas most cloud UC providers offer 99.999%. One nine may not seem like a lot, but it’s the difference between 5.26 and 52.56 minutes of unscheduled downtime per year
  • Contact center features - While Teams Phone System provides basic queuing capabilities, some companies, or specific groups, may require more advanced capabilities, including omnichannel customer engagement, analytics, and call management solutions optimized for specific roles such as sales
  • Messaging requirements - Teams Phone System does not natively integrate SMS/MMS to enable use of a single business number for both calling and texting
  • Cost - Adding Microsoft Phone System to existing licenses may require an additional cost, plus the cost of PSTN connectivity. Often, competing cloud calling providers will offer services that bundle PSTN calling at a lower cost, with greater regional coverage,compared to what is available from Microsoft.

For those that do decide to use Teams Phone System as their calling app, the next decision point is how to connect Teams to the PSTN. Metrigy data shows that the majority of companies (63.4%) rely on Direct Routing where they use new or existing session border controllers to interface Teams Phone System with a SIP trunking provider. About 15% use Operator Connect which allows for configuring of SIP trunking directly from within the Teams Operator Console. Another 9.8% purchase Microsoft’s own Calling Plan which provides a limited number of domestic (with optional international minutes) for a fixed monthly price. Direct Routing popularity is primarily driven by the desire of enterprises to save money. Metrigy cost data shows that Direct Routing is, on average, about 56% cheaper than Calling Plan, and Direct Routing allows for connectivity in counties not supported by Calling Plan.

It’s important to note that choosing between using the Teams Phone System native experience or adding calling to Teams via third-party integration isn’t an all or nothing decision. Companies can deploy a mix of solutions provided they work with a provider capable of supporting different personas. For example, a person with minimal calling needs may find the native Teams Phone System client meets their needs, while someone who requires advanced call queuing and analytics, or contact center features may benefit from using a third-party calling platform. In our data, more than 63% of those who use Microsoft Teams use a separate cloud-based calling provider and just 11.2% plan to deploy the Teams Phone System native client.

For those who do see value in using both the Teams Phone System calling features as well as a third-party calling provider, it’s critical to select a provider that easily supports both. For example, some UCaaS providers such as 8x8 are capable of delivering integrated Direct Routing to support PSTN connectivity for individuals using Teams Phone System. In some cases, UCaaS providers with Direct Routing support will offer additional functionality, even for those using the Teams calling app. Examples include integrated CCaaS, support for SMS/MMS and fax, third-party application integrations (e.g. CRM), and presence awareness between UCaaS and Teams. Using a single provider for both UCaaS and Direct Routing provides unified management and administration as well.

Choosing the right Teams calling solution requires understanding both the needs of your users as well as the available solutions on the market. Consider one that provides deployment flexibility to support integration between the Teams native calling experience and a broader set of features available from a third-party UCaaS provider.