Merge branch 'master' of https://github.com/MicrosoftDocs/azure-docs-pr into cachepurge

Author: duongau

articles/communication-services/concepts/join-teams-meeting.md

@@ -33,6 +33,8 @@ Custom applications built with Azure Communication Services to connect and commu
 
 As with Teams anonymous meeting join, your application must have the meeting link to join, which can be retrieved via the Graph API or from the calendar in Microsoft Teams. The name of BYOI users displayed in Teams is configurable via the Communication Services Calling SDK and they're labeled as “external” to let Teams users know they haven't been authenticated using Azure Active Directory. When the first ACS user joins a Teams meeting, the Teams client will display a message indicating that some features might not be available because one of the participants is using a custom client.
 
+A Communication Service user will not be admitted to a Teams meeting until there is at least one Teams user present in the meeting. Once a Teams user is present, then the Communication Services user will wait in the lobby until explicitly admitted by a Teams user, unless the "Who can bypass the lobby?" meeting policy/setting is set to "Everyone".
+
 During a meeting, Communication Services users will be able to use core audio, video, screen sharing, and chat functionality via Azure Communication Services SDKs. Once a Communication Services user leaves the meeting or the meeting ends, they can no longer send or receive new chat messages, but they will have access to messages sent and received during the meeting. Anonymous Communication Services users cannot add/remove participants to/from the meeting and they cannot start recording or transcription for the meeting.
 
 Additional information on required dataflows for joining Teams meetings is available at the [client and server architecture page](client-and-server-architecture.md). The [Group Calling Hero Sample](../samples/calling-hero-sample.md) provides example code for joining a Teams meeting from a web application.