Universal Serial Bus
Specification
Compaq
Hewlett-Packard
Intel
Lucent
Microsoft
NEC
Philips
Revision 2.0
April 27, 2000
Universal Serial Bus Specification Revision 2.0
ii
Scope of this Revision
The 2.0 revision of the specification is intended for product design. Every attempt has been made to ensure a
consistent and implementable specification. Implementations should ensure compliance with this revision.
Revision History
Revision Issue Date Comments
0.7 November 11, 1994 Supersedes 0.6e.
0.8 December 30, 1994 Revisions to Chapters 3-8, 10, and 11. Added
appendixes.
0.9 April 13, 1995 Revisions to all the chapters.
0.99 August 25, 1995 Revisions to all the chapters.
1.0 FDR November 13, 1995 Revisions to Chapters 1, 2, 5-11.
1.0 January 15, 1996 Edits to Chapters 5, 6, 7, 8, 9, 10, and 11 for
consistency.
1.1 September 23, 1998 Updates to all chapters to fix problems identified.
2.0 (draft 0.79) October 5, 1999 Revisions to chapters 5, 7, 8, 9, 11 to add high
speed.
2.0 (draft 0.9) December 21, 1999 Revisions to all chapters to add high speed.
2.0 April 27, 2000 Revisions for high-speed mode.
Universal Serial Bus Specification
Copyright © 2000, Compaq Computer Corporation,
Hewlett-Packard Company, Intel Corporation, Lucent Technologies Inc,
Microsoft Corporation, NEC Corporation, Koninklijke Philips Electronics N.V.
All rights reserved.
INTELLECTUAL PROPERTY DISCLAIMER
THIS SPECIFICATION IS PROVIDED TO YOU “AS IS” WITH NO WARRANTIES WHATSOEVER,
INCLUDING ANY WARRANTY OF MERCHANTABILITY, NON-INFRINGEMENT, OR FITNESS FOR
ANY PARTICULAR PURPOSE. THE AUTHORS OF THIS SPECIFICATION DISCLAIM ALL LIABILITY,
INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PROPRIETARY RIGHTS, RELATING TO USE
OR IMPLEMENTATION OF INFORMATION IN THIS SPECIFICATION. THE PROVISION OF THIS
SPECIFICATION TO YOU DOES NOT PROVIDE YOU WITH ANY LICENSE, EXPRESS OR IMPLIED,
BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS.
All product names are trademarks, registered trademarks, or servicemarks of their respective owners.
Please send comments via electronic mail to techsup@usb.org
For industry information, refer to the USB Implementers Forum web page at http://www.usb.org
Universal Serial Bus Specification Revision 2.0
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Acknowledgement of USB 2.0 Technical Contribution
The authors of this specification would like to recognize the following people who participated in the USB
2.0 Promoter Group technical working groups. We would also like to thank others in the USB 2.0
Promoter companies and throughout the industry who contributed to the development of this specification.
Hub Working Group
John Garney Intel Corporation (Chair/Editor)
Ken Stufflebeam Compaq Computer Corporation
David Wooten Compaq Computer Corporation
Matt Nieberger Hewlett-Packard Company
John Howard Intel Corporation
Venkat Iyer Intel Corporation
Steve McGowan Intel Corporation
Geert Knapen Royal Philips Electronics
Zong Liang Wu Royal Philips Electronics
Jim Clee Lucent Technologies Inc
Jim Guziak Lucent Technologies Inc
Dave Thompson Lucent Technologies Inc
John Fuller Microsoft Corporation
Nathan Sherman Microsoft Corporation
Mark Williams Microsoft Corporation
Nobuo Furuya NEC Corporation
Toshimi Sakurai NEC Corporation
Moto Sato NEC Corporation
Katsuya Suzuki NEC Corporation
Electrical Working Group
Jon Lueker Intel Corporation (Chair/Editor)
David Wooten Compaq Computer Corporation
Matt Nieberger Hewlett-Packard Company
Larry Taugher Hewlett-Packard Company
Venkat Iyer Intel Corporation
Steve McGowan Intel Corporation
Mike Pennell Intel Corporation
Todd West Intel Corporation
Gerrit den Besten Royal Philips Electronics
Marq Kole Royal Philips Electronics
Zong Liang Wu Royal Philips Electronics
Jim Clee Lucent Technologies Inc
Jim Guziak Lucent Technologies Inc
Par Parikh Lucent Technologies Inc
Dave Thompson Lucent Technologies Inc
Ed Giaimo Microsoft Corporation
Mark Williams Microsoft Corporation
Toshihiko Ohtani NEC Corporation
Kugao Ouchi NEC Corporation
Katsuya Suzuki NEC Corporation
Toshio Tasaki NEC Corporation
Universal Serial Bus Specification Revision 2.0
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Universal Serial Bus Specification Revision 2.0
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Contents
CHAPTER 1 INTRODUCTION
1.1 Motivation.............................................................................................................................................. 1
1.2 Objective of the Specification............................................................................................................... 1
1.3 Scope of the Document.......................................................................................................................... 2
1.4 USB Product Compliance ..................................................................................................................... 2
1.5 Document Organization........................................................................................................................ 2
CHAPTER 2 TERMS AND ABBREVIATIONS
CHAPTER 3 BACKGROUND
3.1 Goals for the Universal Serial Bus ..................................................................................................... 11
3.2 Taxonomy of Application Space......................................................................................................... 12
3.3 Feature List.......................................................................................................................................... 13
CHAPTER 4 ARCHITECTURAL OVERVIEW
4.1 USB System Description ..................................................................................................................... 15
4.1.1 Bus Topology................................................................................................................................. 16
4.2 Physical Interface ................................................................................................................................ 17
4.2.1 Electrical......................................................................................................................................... 17
4.2.2 Mechanical ..................................................................................................................................... 18
4.3 Power.................................................................................................................................................... 18
4.3.1 Power Distribution ......................................................................................................................... 18
4.3.2 Power Management........................................................................................................................ 18
4.4 Bus Protocol......................................................................................................................................... 18
4.5 Robustness............................................................................................................................................ 19
4.5.1 Error Detection............................................................................................................................... 19
4.5.2 Error Handling................................................................................................................................ 19
4.6 System Configuration.......................................................................................................................... 19
4.6.1 Attachment of USB Devices........................................................................................................... 20
4.6.2 Removal of USB Devices............................................................................................................... 20
4.6.3 Bus Enumeration............................................................................................................................ 20
