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 of standardized industry-standard USB. The specification describes the characteristics of USB bus, agreement, transaction type, bus management, interface design programming, as well as the establishment of systems, peripheral equipment manufacturing standards.)