# Call detection > How Curtains notices you're on a call, and opens Curtains Presenter so it's ready in your meeting app's share list. Source: https://curtains.app/help/call-detection/ When you join a call, Curtains notices and opens **Curtains Presenter** behind your windows, so it is already in your meeting app's share list when you click Share. With **Open Curtains Presenter at launch** on, it's often open already: Curtains opens it, blank, when it starts. ## What happens when a call starts If no session is running, Curtains Presenter opens in **standby**. Standby shows only a "Starting soon" card. If it's already open and blank, it switches to that card for the call. It has no windows on it, and nothing is captured. The Presenter opens behind all your other windows. It never takes focus, never covers what you're doing and never opens minimized. It lives on your current desktop (Space), so it doesn't follow a meeting app that is full screen in its own Space. Studio tells you what's going on. In the **Sources** sidebar, a notice at the top reads "You're on a Zoom call: Curtains Presenter is ready to share. Pick windows to show." If Curtains doesn't know the app, it says "You're on a call". *Image: The top of Studio's Sources sidebar with a green notice: “You're on a Google Meet call: Curtains Presenter is ready to share. Pick windows to show.”* Pick your windows, then click **Go Live**. The standby window becomes your session in the same window, so a meeting app that is already looking at it keeps sharing it. See [Drafts and Go Live](https://curtains.app/help/drafts-and-go-live/). The notice follows you through the steps. In a draft it reads "Nothing is shared yet. Go Live when you're ready, then share Curtains Presenter in it." After Go Live it reads "Share the Curtains Presenter window in it." See [Sharing in your meeting app](https://curtains.app/help/sharing-in-your-meeting-app/) for where to click in each meeting app. ## How Curtains knows Curtains asks macOS two questions: is the microphone in use, and by which app? It also asks whether a camera is in use. It never records anything. - **A meeting app on the microphone is a call.** Curtains knows Zoom, Microsoft Teams, Slack, Webex, FaceTime, Discord, Around, Whereby, Skype, GoTo Meeting, Amazon Chime, BlueJeans, RingCentral, Tuple, Pop and Lark. - **A browser counts only with both signals.** The browser must be on the microphone, and one of its window titles must look like a web meeting: Google Meet, Microsoft Teams, the Zoom web client, Whereby, Jitsi Meet, Webex or Slack. Supported browsers are Chrome, Arc, Safari, Edge, Firefox, Brave, Vivaldi and Opera. - **Muted calls count.** Meet, Teams and Zoom keep the microphone open while you're muted. - **A meeting window alone is not a call.** A Meet tab keeps its title on the pre-join page and after you leave, so Curtains waits for the microphone too. - **A camera can stand in.** If a meeting window is open and your camera is in use, that counts as a call even when you joined without audio. - **An unknown app counts only with a camera.** The microphone alone, from an app Curtains doesn't know, is not a call. A call is confirmed after about two seconds. It ends about ten seconds after the signals stop. On macOS 13, Curtains can only tell that the microphone is in use somewhere, not which app has it, so detection is less exact than on macOS 14 and later. > **Nothing leaves your Mac** > > Call detection runs locally. It asks for no new permission, and it records, stores and sends nothing: not the call, not the window titles it matches against. Usage stats only say that a call started and the kind of app, if you have usage stats on. See [Usage stats and privacy](https://curtains.app/help/usage-stats-and-privacy/). ## See the call status The menu bar icon shows **On a Zoom call**, **On a call** or **No call detected**. *Illustration: The Curtains menu bar menu during a Zoom call with no session running: Open Curtains Studio, On a Zoom call, Go Live, Show remote, Bring to front, Hidden from screenshots during this call, Allow screenshots for 5 minutes and Quit Curtains.* Curtains keeps checking while it runs. Closing Studio only hides it, so detection keeps working. That is the setting **Keep running in the menu bar when Studio is closed**, on by default. To have Curtains running after a restart, turn on **Launch at login** in **Settings › General**. ## When the call ends A standby Presenter closes 30 seconds after the call ends, unless **Open Curtains Presenter at launch** is on. Then it goes back to blank and stays open. If a call starts again within that time, the window stays. A session that is running is left alone. If you close the standby Presenter during a call, or stop a session, Curtains doesn't reopen it for that call. Go Live again to get it back. ## The Go Live reminder If a session in a call stays Paused for 20 seconds before you first go Live, Studio shows a banner, "You're in a call and viewers see the holding card," and a ring around the floating remote's **Go Live** button pulses. See [Live, Paused and End](https://curtains.app/help/live-paused-and-end/#the-go-live-reminder). ## Change how it behaves Open **Settings › Calls**. *Image: Settings, Calls section, During calls: Open Curtains Presenter when a call starts, Show floating remote when Studio isn't in front, and Remind me to go Live, each with a switch that is on.* - **Open Curtains Presenter when a call starts** is on by default. Turn it off and a call doesn't open it. You can still Go Live, and Curtains Presenter opens then. To stop it opening at launch too, turn off **Open Curtains Presenter at launch** in **Settings › Presenter**. - **Show floating remote when Studio isn't in front** is on by default. - **Remind me to go Live** is on by default. Off, there is no banner and the Live button doesn't pulse. Detection itself has no switch. It is local and sends nothing. By default, Curtains also hides its own windows from screen sharing while a call is detected. See [Screenshots and screen sharing](https://curtains.app/help/screenshots-and-screen-sharing/). ## Related - [Sharing in your meeting app](https://curtains.app/help/sharing-in-your-meeting-app/): where to find Curtains Presenter in Meet, Zoom, Teams and Slack. - [Floating remote and menu bar](https://curtains.app/help/floating-remote-and-menu-bar/): control the session during the call. - [Troubleshooting](https://curtains.app/help/troubleshooting/): Curtains Presenter isn't in the share list.