Copyright © 2023 USB Promoter Group. All rights reserved.
Universal Serial Bus 4 (USB4®)
Specification
Apple Inc.
HP Inc.
Intel Corporation
Microsoft Corporation
Renesas Corporation
STMicroelectronics
Texas Instruments
Version 2.0 with Errata and ECN through June 29, 2023
October 2022June 2023
Version 2.0 - ii - Universal Serial Bus 4
June 2023 Specification
Copyright © 2023 USB Promoter Group. All rights reserved.
Release History
Version
Comments
Issue Date
1.0
First release
August 2019
1.0 with Errata and ECN through
May 4, 2020
Includes errata and ECN through May 4,
2020 as part of the specification text.
June 2020
1.0 with Errata and ECN through
October 15, 2020
Includes errata and ECN through October
15, 2020 as part of the specification text.
October 2020
1.0 with Errata and ECN through
May 19, 2021
Includes errata and ECN through May 19,
2021 as part of the specification text.
May 2021
2.0
Adds support for Gen 4 (80G) speeds and
Asymmetric Link operation. Also includes
various optimizations for performance
including USB3 Gen T Tunneling, support
for DP 2.1, and an enhanced Time
Synchronization mechanism.
October 2022
2.0 with Errata and ECN through
June 29, 2023
Includes errata and ECN through June 29,
2023 as part of the specification text.
June 2023
Version 2.0 - iii - Universal Serial Bus 4
June 2023 Specification
Copyright © 2023 USB Promoter Group. All rights reserved.
NOTE: Adopters may only use this USB specification to implement USB or third party
functionality as expressly described in this Specification; all other uses are prohibited.
LIMITED COPYRIGHT LICENSE: The Promoters grant a conditional copyright license under the
copyrights embodied in this USB Specification to use and reproduce the Specification for the
sole purpose of, and solely to the extent necessary for, evaluating whether to implement
the Specification in products that would comply with the specification. Without limiting the
foregoing, use of the Specification for the purpose of filing or modifying any patent
application to target the Specification or USB compliant products is not authorized. Except
for this express copyright license, no other rights or licenses are granted, including without
limitation any patent licenses. In order to obtain any additional intellectual property
licenses or licensing commitments associated with the Specification a party must execute
the USB Adopters Agreement. NOTE: By using the Specification, you accept these license
terms on your own behalf and, in the case where you are doing this as an employee, on
behalf of your employer.
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
FOR INFRINGEMENT OF ANY PROPRIETARY RIGHTS, RELATING TO THE 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.
Please send comments to techsup@usb.org.
For industry information, refer to the USB Implementers Forum web page at
http://www.usb.org.
USB Type-C
®
, USB-C
®
, USB 2.0 Type-C™, and USB4
®
are trademarks of the Universal Serial Bus
Implementers Forum (USB-IF). DisplayPort™ is a trademark of VESA. All product names are
trademarks, registered trademarks, or service marks of their respective owners.
Thunderbolt™ is a trademark of Intel Corporation. You may only use the Thunderbolt™
trademark or logo in conjunction with products designed to this specification that complete
proper certification and executing a Thunderbolt™ trademark license – see usb.org/compliance
for further information.
Copyright © 2023, USB Promoter Group (Apple Inc., HP Inc., Intel Corporation, Microsoft
Corporation, Renesas Corporation, STMicroelectronics, and Texas Instruments).
Version 2.0 - iv - Universal Serial Bus 4
June 2023 Specification
Copyright © 2023 USB Promoter Group. All rights reserved.
Acknowledgement of Technical Contribution
The authors of this specification would like to recognize the following peo ple who participated
in the USB4 Specification technical work group.
Apple Inc. – Promoter Company Employees
Majd Abu Tayeh
Nimrod Agmon
Lior Aloni
Brian Baek
Omer Bar-Lev
Ryan Bartling
Sariel Ben-Arye
Moshe Benyamini
Gopu Bhaskar
Ilan Bendor
Jonathan Brown
Carlos Calderon
Kok-Wui Cheong
David Conroy
Bill Cornelius
Scott Deandrea
Emerson Fang
William Ferry
Amit Flanter
Itay Franko
Radia Gantous
Alex Gerber
Lian Ghattas
Shay Glam
Mark Goikhman
Nir Guetta
Sumeet Gupta
Yair Hershkovitz
Derek Iwamoto
Scott Jackson
Husam Khashiboun
Ofir Klinger
Alan Kobayashi
Alexei Kosut
Christine Krause
Dmitri Krichevsky
Gilad Levi
Mitchell Lichtenberg
Alex Lopatinsky
Alex Lozovik
Sanjeev Maheshwari
Timoth McIntosh
Rachel Menes
Shlomi Mor
Shlomi Museri
Mona Omari
James Orr
Tal Ostro
Sridhar Pavithrapu
Arie Peled
Collin Pieper
Kaushik Poluri
Idan Reller
Jafar Savoj
Ori Scher
Reese Schreiber
Oleg Schtofenmaher
Niv Shevil
Etan Shirron
Ori Moshe Stern
Jose Tierno
Maxim Tsudik
Anatoly Uskach
Vishal Varma
Jeff Wilcox
Dan Wilson
Ohad Zalcman
HP Inc. – Promoter Company Employees
Rami Bathaniah
Roger Benson
Marcus Benzel
Alan Berkema
Kenneth Chan
Frank Chen
Phil Chen
Hosup Chung
Glen Dower
Mark Lessman
Nam Nguyen
Roger Pearson
Osaid Shamsi
Kenneth Smith
Chris Tabarez
Intel Corporation – Promoter Company Employees
Suzan Abbas
Khaled Almahallawy
Nausheen Ansari
Noam Arzy
Alexandre Audier
Binata Bhattacharyya
Nirmala Bailur
Marcin Behrendt
Dmitriy Berchanskiy
Brad Berlin
Meborach Bublil
Chew Chee Mun
Huimin Chen
Hengju Cheng
Salauddin Choudhury
John Crouter
Maxim Dan
Lior David
Oded David
Jhuda Dayan
Imre Deak
Yoni Dishon
Hem Doshi
Gil Fine
Version 2.0 - v - Universal Serial Bus 4
June 2023 Specification
Copyright © 2023 USB Promoter Group. All rights reserved.
Eran Galil
Saranya Gopal
Venkataramani
Gopalakrishnan
Raul Gutierrez
Michael Gouzenfeld
Ngek Leong Guok
Mickey Gutman
Benjamin Hacker
Yaniv Hayat
Uri Hermoni
Jack Huang
Jenny Huang
Alon Horn
Abdul Ismail
Abhilash K V
Ziv Kabiry
Vijaykumar Kadgi
Vijay Kasturi
Sergey Khaykin
Lev Kolomiets
Vladislav Kopzon
Efraim Kugman
Rolf Kuhnis
Edmond Lau
Uriel Lemberger
Xiang Li
Yun Ling
Guobin Liu
Balaji Manoharan
Liran Manor
Uma Medepalli
Assaf Mevorach
Hezi Naaman
Udaya Natarajan
Offir Naveh
Ohad Navon
Naod Negussie
Aruni Nelson
CheeLim Nge
Jim O’Reilly
Vrukesh Panse
Leonid Plaks
Duane Quiet
Vinay Raghav
Kannappan Rajaraman
Priyank Rathod
Rajaram Regupathy
Reuven Rozic
Ravindra Rudraraju
Oren Salomon
Brad Saunders
Leonid Shaposhnik
Ehud Shoor
Ari Sharon
Uri Soloveychik
Ravishankar
Subramanian
Shay Sudman
Einat Surijan
Eliahu Suued
Kai Svahn
Narayanan Thiagarajan
Pranav Tipnis
Aviel Uzan
Karthi Vadivelu
Alex Vekker
Tsion Vidal
Chen Vrubel
Stephanie Wallick
Tzewen Wang
Sarel Wechsler
Ady Weiss
Mika Westerberg
Nancy Yadav
Gal Yedidia
Vladimir Yudovich
Reza M. Zamani
Vitaly Zhivov
Microsoft Corporation – Promoter Company Employees
Randy Aull
Jim Belesiu
Ramamohan Reddy
Boreddy
Martin Borve
Anthony Chen
Jesse Chen
Matt Chung
Aacer Daken
Senthilnathan Duraisamy
Rajib Dutta
Mark Friend
Philip Froese
David Hargrove
Robbie Harris
Lily Huang
Kit Hui
Patrick Law
Mark Lin
Toby Nixon
Arjun Padmanabhan
Sorush Raeisian
Rahul Ramadas
Andrea Severson
Kiran Shastry
Nathan Sherman
James Sun
Ji Sun
Shyamal Varma
Vahid Vassey
Andrew Yang
Tieyong Yin
Renesas Corporation – Promoter Company Employees
Tam Do
Philip Leung
Kiichi Muto
Ziba Nami
