eDog Whistle for iPhone is used in training of dogs and cats. With eDog Whistle, you can simply attract a dogs attention or stop his barking. It features adjustable sliders for active control of the frequency produced; bark detector and sound meter, and about seven styles sound pattern. You can try to adjust the frequency of the tone while your dog is sleeping; until your dogs ears perk up. Those frequencies that your dog is sensitive to can be used for training your dog. Different sound patterns can be used to trigger different responses. For example, two short bursts could mean stop and one long burst could mean lie down.