What are the differences between USB Rev1.1 and USB Rev2.0?

USB 2.0 is the upgraded version of USB 1.1 and features a new optional "High Speed" mode in addition to "Low Speed" and "Full Speed" modes supported by the Rev.1.1. The "High Speed" mode offers a data transfer rate of up to 480 Mbps, which shortens the operation time to use storage devices such as hard disc, CD-R/RW and MO at high speed compared with Rev.1.1. In addition, USB 2.0 is fully compatible with USB 1.1. It is important to note that the High Speed mode is realized only when all devices including a USB hub and cables are compliant with USB 2.0. If USB 1.1-complient devices are used in a circuit, the data transfer rate is automatically slowed down to the Low Speed mode or the Full Speed mode. USB 2.0-compatible OS drivers are as follows. - Windows XP...Service Pack 1 or later - Windows 2000...Service Pack 2 or later - Mac OS X...10.2.8 or later