With the Cloud Video Interop (CVI) Service for Microsoft Teams, the user can call into a Teams meeting from any standards based Video Teleconference (VTC) system on SIP and H.323.
So, let's see how you invite people to join a Teams meeting...
Inviting to a Teams meeting
Simply invite VTC users to a Teams meeting in the same way any other users are invited. You can invite using Outlook or Teams.
The invite will automatically contain dial-in information for all participants:
Note for Outlook users: the first time you invite, you may see that the meeting invite does not contain any new information. This is due to Outlook caching the previous meeting information. You therefore need to make two invitations for the new information to appear.