A button on a MIDI controller or sequencer that, when pressed, sends an all notes off message to all connected MIDI receivers. Doing so silences any stuck notes that may be occurring. Panic buttons are also provided by computer sequencer software as a clickable button in a window, or a key or combination of keys on the computer’s alpha keyboard to press. For most PC sequencer software, the ESC key is a panic button; for Mac software, it is usually the Command-period or Apple-period key combination.