With the Intercom hotkey, you can send Intercom messages with a push of a key on your keyboard. Once the Intercom hotkey is defined, users with administrator and Intercom privileges can use this keyboard shortcut to send announcements. See How to Access the Intercom - CO.
Your System manager has to define the hotkey on the Intercom tab of the System module, which performs the same action as the Push-to-Talk button on the user interface.