public interface RemoteControl {
  boolean powerOnOff();                                                // Returns new state, on = true
  int volumeUp(int increment);                                         // Returns new volume level
  int volumeDown(int decrement);                                       // Returns new volume level
  void mute();                                                         // Mutes sound output
  int setChannel(int channel);                                         // Set the channel number and return it
  int channelUp();                                                     // Returns new channel number
  int channelDown();                                                   // Returns new channel number
}