A patent published in September 2010 revealed that Apple was working on a new headphone design that would allow for much smaller inputs on iPhones and iPod Touches., but in the end the iPad 2 was the first to use it, since in addition to being very thin, the new device has a curved back.
This also happened in the original iPhone, which led to the fact that you could only use Apple headphones, in the new iPad you can use any headset despite the fact that when you connect it a large part of it stays out of the hole.
The patent mentioned used a system based on pins that, with a retractable part, were extended to create contact with the connected headset.. This technology allows Apple to create much thinner devices.
via |Mac stories
