Electronic device circuitry for communicating with accessories

摘要: Electronic devices and accessories such as headsets for electronic are provided. A microphone may be included in an accessory to capture sound associated device. Buttons other user interfaces the accessories. An have audio plug that connects a mating jack device, thereby establishing wired communications link between The device include power supply circuitry applying bias voltages accessory. adjust settings related operating modes. User input information conveyed using ultrasonic tone transmission. also gather from voltage detector coupled lines path.