The United States Patent & Trademark Office (USPTO) has once again published details of a patent application that provides us with an insight into a potential Apple product. The patent filing - titled "Audio class-compliant charging accessories for wireless headphones and headsets" - outlines an intelligent hybrid headphone system that knows whether to switch to a wired or wireless connection based on the type of audio data it receives from a connected device. This transition between states would be automated, instant, and handled without fuss by the device's built-in "control circuitry".