It's an application leaves your microphone mute except while holding down a keyboard button or mouse button. When the Application starts, it will add a microphone status icon to the menu bar.
The application can be downloaded in the releases section. Drag the application into the /Applications folder. Right click and select open to start.
- Hold alt ⌥option key to talk, and release to mute.
- Hold a non-primary mouse button or presentation clicker to talk, and release to mute.
- Click on the menu bar icon and select 'Disable PTT' to disable push to talk and leave the mic on all the time.
The mic icon indicator will be red if microphone is unmuted.
I did not sign the App. To enable exception for this app follow https://support.apple.com/kb/PH11436?locale=en_US If you want to be sure, just compile the project, Archive & export PushToTalk.app