With Apple widely believed to be planning to drop the headphone socket in the iPhone 7 in favor of Lightning-connected and wireless headphones, a patent application published today describes how a single set of headphones could switch smoothly between wired and wireless modes without any interruption of playback.
There’s of course nothing new in headphones that support both wired and wireless use – many Bluetooth headphones come supplied with a plug-in audio cable that allow them to fall back to wired use if they run low on battery power or you just want the higher quality a wired connection typically delivers.
But switching between wired and wireless use typically has a couple of issues, and Apple’s patent aims to solve both of them …
First, the phone may not automatically connect to the correct Bluetooth device if there are several known connections within range. Second, even if the phone does choose the correct device, it still takes a few seconds to establish the link and begin playing.
To address the first issue, Apple proposes that the headphones are coded in some way (the patent is a little vague on the details) so that the phone knows that the wireless device is the same as the wired one, and it should continue transmitting audio to it.
The method can include determining that the user device connected via the wired connection is the same user device as is connected via the wireless connection.
To tackle the second, Apple wants to include a data buffer in the circuitry of the headphones, allowing audio to continue to play from that buffer during the handover.
The processor can seamlessly transition speaker control between data received via the wireless transceiver and data received via the second contact. In some embodiments, the data buffer can be sized to operate the headphone for a predetermined amount of time without the receipt of additional data via the wireless transceiver or the second contact. This length of time can be greater than the length of time required to transition between storing data from the wireless transceiver into the buffer to storing data from the connector into the buffer.
The headphones would also keep track of the exact point at which one audio source ends and the second begins, so that the whole process is completely transparent to the user – you’ll just plug in or unplug and the audio will continue as if nothing had happened.
Finally, the patent describes how a single cable can supply both audio and power, which would allow the headphones to be charged from an iPhone. This may raise concerns from some about the battery-life of the phone, but certainly the complete tech package the patent describes sounds very cool.