Introduction: This article is a continuation of a series of articles on Azure services starting with the signal R service we described earlier. The Azure communication service is a cloud-based service that allows communication into your application communication in the form of voice and video calling rich text chat and SMS. The applications are relieved from knowing the media encodings and real-time networking requirements of using these communication technologies in a do-it-yourself approach and are instead onboarded to a welcoming SDK.  Custom client endpoints, services, and even publicly switched telephone networks can be connected to this communications application. Even phone numbers can be acquired directly. Services can make use of Session Initiation Protocol (SIP) and session border controllers which connect PSTN carriers 

Applications that make use of the Azure communication services client libraries leverage one of the following two common scenarios: 1) business to consumer scenario and the 2) consumer to consumer scenario.  The B2C scenario is focused on voice, video, and text chat available from a custom browser or mobile application for individuals’ interaction with a business. It operates with a voice response system as well as integration with Microsoft Teams which is a communication and collaboration tool that facilitates employees of an organization to communicate with one another.  The consumer-to-consumer scenario is built on engaging social spaces with voice video and rich text chat.  As with all Azure services, the communication services also provision an Azure resource declared via an Azure resource manager template.  When the resource is provisioned, it can be used to get a phone number or to send an SMS from the application. The first user access token allows the clients to authenticate. Afterward, it's just renewed. The use of an arm resource template helps with the standardization of this resource in the Azure service portfolio. Like other services, it provides connection strings and a resource object to manage and use. The resource group name and the subscription are required for this resource to be provisioned settings may vary but they can be specified as parameters to the template. Cleanup is as easy as removing the resource group to which the resource belongs and for the removal of all dependencies. 

When the application is used to get a phone number the provisioned resource allows the selection of a number type and the capabilities associated with the number and the geographies and toll-free are two types of numbers. A toll-free number helps with the outbound calling and inbound and outbound SMS features and is slightly more expensive than the geographies number type. Phone numbers can be customized and even purchased. Registration of phone number, its lookup, and reverse lookup could be tried via the Azure portal. 

The application can also send SMS messages. A simple object model can be used to represent the resource in the CSharp language, and the SMS client can be instantiated with the help of a connection string and authenticated with the server, then it is a matter of justice calling the send method on the SMS client to send a direct message. It is also possible to broadcast a message by including multiple phone numbers as a parameter to the send method. 

Integration with other applications such as Microsoft Teams makes this service uniquely appealing for collaboration and communication scenarios. For example, this application can be joined to a team meeting with a UI control that declares a text box on a form to take the team's meeting link. With a click of a button, the application can connect to the team's meeting. JavaScript callbacks can be registered for events such as isRecordingActive, changed state, and others. The benefits of voice, video, and rich text chat cannot be overemphasized in gaining user attention.