The plug and socket that provides data transfer between an iPhone, iPad or iPod and a computer or sound system. Using a 30-pin, proprietary configuration, the Apple device contains the socket, and the cable or docking station has the plug. In 2012, the digital+analog 30-pin interface was changed to an all-digital 8-pin interface on certain new models (see Lightning connector). Digital and Analog The 30-pin Apple dock connector uses 27 digital lines for USB 2.0, USB 3.0 and DisplayPort interfaces, plus three lines for analog audio. However, all Apple devices have another analog output: the standard 3.5mm earphones jack, which is also commonly used to connect to a stereo system or a boom box that has analog inputs (see mini-phone connector).