说明：  本书规范了USB的工业标准。该规范介绍了USB的总线特点、协议内容、事务种类、总线管理、接口编程的设计，以及建立系统、制造外围设备所需的标准。
(The book industry standard specifications of the USB. The specification describes the characteristics of the USB bus, agreement, transaction types, bus management, interface programming, design, and building systems, manufacture of peripherals required standards.)