In order to enable faster data transfer while maintaining compatibility with USB 1.x, the USB 2.0 specification includes the following 4 requirements:

  1. 480 Mbps bus operation for a dramatic improvement in bandwidth.
  2. Same cables and connectors as USB 1.x for physical compatibility.
  3. Support for both 12/1.5 Mbps data transfer and 480 Mbps data transfer.
  4. Measures to prevent 12/1.5 Mbps data transfers from occupying the bandwidth for 480 Mbps data transfers.

 

USB2.0 Basic Specifications