https://www.wired.com/story/some-cheap-wired-headphones-are-actually-using-bluetooth/
Some Cheap Wired Headphones Are Actually Using Bluetooth
> But Apple also has strict certification called MFi ... companies have to pay for the privilege of being a genuine Apple accessory ... This has led to earbuds that use roundabout ways of connecting to Apple’s proprietary port. Namely, by requiring a Bluetooth connection ...
No me lo acabo de creer, pero curioso.