A toggle key is any key on the keyboard that can switch between two states. The Num Lock, Caps Lock, and Scroll Lock keys are toggle keys. Most toggle keys have an associated light emitting diode (LED) on the keyboard that lights when the toggle key is active. To assist users with visual impairments, you can customize the keyboard to emit an audible notification when a user presses a toggle key. For example, when you press Num Lock, you can determine whether the key is toggled or not toggled by the sound.
To enable accessible toggle keys, select the Enable Toggle Keys option. When you activate the Num Lock, Caps Lock, or Scroll Lock keys, the system beeps once. When you deactivate a toggle key, the system beeps twice.