The U.S. Patent and Trademark Office published an Apple patent today that describes a hybrid analog/digital stereo headphone system capable of switching seamlessly between wired and wireless audio modes (via AppleInsider).
The patent for "Audio class-compliant charging accessories for wireless headphones and headsets" distinguishes the system from traditional headphones by its use of an electrical connector capable of transmitting both digital and analog signals, which would make it compatible with Apple's proprietary Lightning connector protocol.
The wired contacts in the connector utilize "differential signaling" that enable it to transfer power and audio data through a single cable without compromising sound quality, while the wireless component of the headphones comprises an internal battery, processor, memory, and antenna for communicating with a source device such as an iPhone.
Design details are sparse, but the patent notes that the hardware would fit into in-ear, on-ear and over-ear styles of headphones.
As with all Apple patents, the usual caveat applies in that the invention may not see the light of day in any future product. That said, the system it describes is consistent with rumors that Apple plans to ditch the headphone jack for the fall 2016 iPhone 7 in favor of a Lightning-equipped headphone accessory or Bluetooth-based wireless listening solution similar to the Bragi Dash headphones.