This feature is deprecated. Use Team Voice Calls to enable VoIP in Rocket.Chat.
After you make yourself available to receive/make calls, you can start taking inbound calls.
Call operations
As an agent, you can handle the following call operations:
Call in progress
Click the Accept button to accept the call. The ongoing call appears as shown below:
Ongoing call
Please note that messages are not available on a phone call room.
Mute and unmute call
You have controls to mute/unmute calls.
Mute/Unmute
Hold and resume calls 
If your workspace is subscribed to any of Rocket.Chat's premium plans, you can hold and resume calls according to your workflow needs.
Hold/Unhold
Device settings
Switching devices during an ongoing call is available to workspaces subscribed to any of Rocket.Chat's premium plans.
Device settings
Call wrap-up
After the call ends you can leave your notes in the call wrap-up. This feature is only available to workspaces subscribed to any of Rocket.Chat's premium plans.
Call wrap-up