If using pearled barley, add 1 cup pearled barley, 2 cups cold water and a pinch of salt to the rice cooker.
If using brown barley, add 1 cup brown barley, 2 1/2 cups water and a pinch of salt to the rice cooker and let soak overnight, or at least one hour before cooking if you're pressed for time.
Turn the rice cooker on and let the barley cook until the rice cooker turns off automatically.
Let the barley rest for 15 minutes.
Fluff the barley with a fork and serve, or use in your favorite recipes.