Micro USB is a portable version of the USB 2.0 standard, which is smaller than the Mini USB interface used by some mobile phones. Micro-USB is the next-generation specification of Mini-USB. It was established in 2007 by the USB Implementers Forum (USB-IF) of the United States, the USB Standardization Organization. The formulation was completed on January 4th. Micro-USB supports OTG, and like Mini-USB, it is also 5pin. The definition of the Micro series includes the Micro-B series socket used by standard equipment; the Micro-AB socket used by OTG equipment; Micro-A and Micro-B plugs, as well as cables.