This post is about Azure Communication Services (ACS), what it is and what’s ACS Direct Routing. Azure Communication Services (ACS) are platform services for developing your own communication services based on Azure. Microsoft Teams leverages these as well. ACS enables you develop using ACS APIs for communication, video and SMS.

Developing on ACS offers you rich capabilities regarding voice and video calling, chat, SMS and telephony. As far as I could see it is very well documented by Microsoft. You can find plenty of documentation and also code samples, to start with.

The news here is that Direct Routing support with certified Session Border Controllers (SBCs) comes to ACS. By this you can not only just buy telephony numbers which is restricted to paid Azure US subscriptions, with a US billing address, at the moment. Direct Routing enables you to bring your own PSTN SIP Trunk or PBX SIP Trunk and connect it to ACS. Where you deploy the SBC is up to you, if it is a certified one. SBCs can be hardware or virtual appliances running wherever the vendor supports it. Right now, there’s only one certified SBC from Metaswitch but the list of certified SBCs is surely going to be extended with other SBCs in the future, I’d guess.

Pricing seems to be consumption based which means if you develop your app you have to pay as you go, or in other words, e.g. you have to pay per chat message, phone call etc. You can find some examples on the docs, also listed in the additional resources as a source and reference.

Conclusion, opinion and summary

ACS is a platform, a Communication Platform as a Service (CPaaS), to create your custom communication and collaboration service based on Azure. You can develop services an make it interoperable with your own PSTN or PBX backend infrastructure using a certified SBC, furthermore you can use interop features with Microsoft Teams as well. Some features and capabilities might be in preview, so watch pay attention to the service’s documentation.

In my opinion ACS is a great opportunity for many communication and collaboration vendors and service provider to quickly deploy scalable apps on a global scale without the hassle of managing own infrastructure for service provisioning. I could also imagine that organizations could utilize ACS for completely new customized means of communication and collaboration with customers, suppliers and partners depending on the industry and specific needs of an organization.

Additional resources

• Azure Communication Services: Telefonie (CPaaS) | Microsoft Azure
• What is Azure Communication Services? | Microsoft Docs
• Azure Communication Services | Microsoft Docs [DE]
• Azure Communication Services – Telephony – CPaaS | Microsoft Azure [EN]
• Phone number types in Azure Communication Services – An Azure Communication Services concept document | Microsoft Docs
• Azure direct routing infrastructure requirements – Azure Communication Services | Microsoft Docs
• Azure direct routing certified Session Border Controllers – Azure Communication Services | Microsoft Docs
• Azure direct routing provisioning and configuration – Azure Communication Services | Microsoft Docs
• Teams meeting interoperability – An Azure Communication Services concept document | Microsoft Docs
• Pricing scenarios for Calling (Voice/Video) and Chat – An Azure Communication Services concept document | Microsoft Docs
• GitHub – Azure/Communication: Azure Communication Services – Samples and Tools
• Overview – Page ⋅ Storybook (azure.github.io)