USB’S full name is Universal Serial Bus. USB supports hot plug, namely the advantages of plug and play, hence it has become the most important interfaces of MP3. USB has two standards, namely, USB1.1 and USB2.0.

USB1.1 is the most commonly used USB specification, and its transmission rate of high-speed mode is 12Mbps, and its transmission rate of at low-speed modeis 1.5Mbps (b refers to Bit), 1MB / s (megabytes / sec) = 8MBbPS (trillion bits / sec), 12Mbps = 1.5MB / s. At present, the majority of MP3 apply to such interface type.

USB2.0 specification is evolved by the USB1.1 specification. Its transfer rate reached 480Mbps, and 60MB / s when converted into MB, which is sufficient to meet most of the peripheral rate of demand. "Enhanced Host Controller Interface" (EHCI) in the USB 2.0 defines a compatible framework with USB 1.1. It can use USB 2.0 to drive USB 1.1 device drivers. In other words, all devices supported USB 1.1 can be directly used on USB 2.0 interface without having to worry about compatibility issues, and accessories like USB cable, plugs, etc. can also be used directly.

Here are several common USB interfaces: