USB是PC體系中的一套全新的工業標準，它支持單個主機與多個外接設備同時進行數據交換。

首先會介紹USB的結構和特點，包括總線特徵、協議定義、傳輸方式和電源管理等等。這部分內容會使USB開發者和用戶對USB有一整體的認識。-USB PC system is the new set of industry standards, It supports a single server with a number of external equipment to exchange data simultaneously. USB will first introduce the structure and features, including bus features, the agreement definition, means of transmission and power management. Make this part of USB developers and users to have a USB overall awareness.