USB

Universal Serial Bus (USB) is an that establishes specifications for cables and connectors and protocols for connection, communication and power supply () between computers and peripherals.
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The USB specification was co-created at Intel by in collaboration with , , IBM, Microsoft, , and . First formally released as USB 1.0 on January 15, 1996, the USB standards are currently maintained by the (USB-IF). There have been four major generations of USB specifications: USB 1.x, USB 2.0, USB 3.x and USB4.
==Version history==
Name 	Released 	Maximum transfer rate 	Note
 USB 0.7 	 	 	Pre-release
 USB 0.8 	1994-12 	 	Pre-release
 USB 0.9 	1995-04-13	Full Speed (12 Mbit/s) 	Pre-release
 USB 0.99	1995-08 	 	Pre-release
   	1995-11 	 	Release Candidate
 USB 1.0 	1996-01-15	Low Speed (1.5 Mbit/s)Full Speed (12 Mbit/s)	
 USB 1.1 	1998-08 	Low Speed (1.5 Mbit/s)Full Speed (12 Mbit/s)	
 USB 2.0 	2000-04 	High Speed (480 Mbit/s) 	
 USB 3.0 	2008-11 	Superspeed (5 Gbit/s) 	Also referred to as USB 3.1 Gen 1 and USB 3.2 Gen 1 × 1
 USB 3.1 	2013-07 	Superspeed+ (10 Gbit/s) 	Includes new USB 3.1 Gen 2, also named USB 3.2 Gen 2 × 1 in later specifications
 USB 3.2 	2017-08 	Superspeed+ dual‑lane (20 Gbit/s) 	Includes new Gen 1 × 2 and Gen 2 × 2 multi-lane modes
 USB4 	2019-08 	Dual‑lane (40 Gbit/s) 	Includes new Gen 3 × 1 and Gen 3 × 2 modes and introduces USB4 routing for tunnelling of USB3.x, DisplayPort 1.4a and PCI Express traffic and host-to-host transfers, based on the Thunderbolt 3 protocol
===USB 1.x===
USB 1.1 was introduced with the iMac G3 in 1998. At the time, it was considered a shock to the classic Mac OS user base because it replaced several legacy connectors, such as ADB, GeoPort, and SCSI. However, Apple Computer's adoption of the standard drove the rest of the PC industry to quickly embrace it.#1 Temporal Loop - Birth of the iMac by Thomas Hormby, The Mac Observer. 2007-05-25. Archived 2007-05-29. Support was built into Mac OS 8.1 and later, but third party PCI cards required a USB Card Support extension. Support for USB drives required a USB Storage Support extension.
===USB 2.0===
USB 2.0 was introduced with the updated Aluminum PowerBook G4, new Power Mac G5, and 3rd generation iPod in 2003. Support was built into Mac OS X 10.2.7 "Jaguar" and later. The Classic environment can recognize USB 2.0 drives through Mac OS X, but booting in Mac OS 9 itself will fall back to USB 1.1 speeds.USB 2.0 in macos9 by supernova777, Mac OS 9 Lives. 2014-09-15.
===USB 3.x===
USB 3.0 was introduced with the updated MacBook Air and MacBook Pro in mid-2012. Support was built into Mac OS X 10.7.3 "Lion" and later. The first iOS device to support USB 3 through its Lightning port was the iPad Pro in 2015. Unlike PC manufacturers which label their USB 3 ports blue, Apple does not designate their computer ports by color. Access to the System Information application can identify the port type.Does my Computer have USB 2.0 or USB 3.0 Ports? by Josh, Tether Talk. 2014-10-21.
===USB4===
USB4 specifies the inclusion of Thunderbolt 3 to the USB-C form factor.USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB by Anton Shilov, AnandTech. 2019-03-04. It was introduced by Apple in November 2020 in new MacBook Air, 13-inch MacBook Pro, and Mac mini models based around the Apple M1 processor.Apple unleashes M1, Apple Inc. 2020-11-10.
==Form factors==
USB connectors came in many formats to accommodate desktop, portable, and mobile equipment. This is distinct from USB version and some connector types were modified to add support for newer versions of USB. Most have been deprecated from future usage (with the exception of USB-C) to reduce confusion in new devices.
===USB-A===
USB Type-A, also known as USB-A, is the ubiquitous USB connector format used in many desktop systems. It was first introduced by Apple Computer in the iMac G3 with support for USB version 1.1. The same connector could be used with Apple devices that supported USB 2, starting in 2003. With the introduction of support for USB 3 in Apple devices in 2012, the connector was modified with 5 additional pins to increase throughput. USB-A cables and ports with USB 3 support look externally similar to older versions, and were often identified with a blue color or "Superspeed" logo. However, Apple has never identified their USB port versions in this manner. Subsets of the USB-A connector have also been introduced for smaller devices, such as Mini-A and Micro-A, though none of these were ever adopted by Apple.USB-A vs. USB-C: What’s the difference? by Tyler Lacoma, Digital Trends. 2020-11-20. As of 2021, Apple has retired the USB-A connector from most of its product line, with the exception of the Mac mini, Intel-based iMac, and Mac Pro.Mac mini vs. Mac Pro: The affordable alternative by Anthony Casella, iMore. 2019-06-22.
===USB-B===
USB Type-B, also known as USB-B, was never designed into any standalone Apple device, but was adopted by many peripherals such as printers and scanners. Subsets of the USB-B connector were introduced for smaller devices, such as Mini-B and Micro-B. Since 2011, Apple has included USB Micro-B adapters with iPhones (which use proprietary connectors) to comply with European Union regulations. A USB Micro-B port was also included on 2nd and 3rd-generation Apple TV models for use by authorized service providers only. Support for USB 3 forced the USB-B and Micro-B connectors to be enlarged to accommodate additional pins. As a result, newer "Superspeed" USB-B cables can only be used on USB 3 devices; older USB-B cables are backwards compatible and can also be used on USB 3 devices, but at slower USB 2 speeds.Apple releases Micro USB adapter for iPhone by Dieter Bohn, The Verge. 2011-10-04.Identify your Apple TV model, Apple Inc. 2019-03-25.
===USB-C===
USB Type-C, also known as USB-C, was introduced with the MacBook with Retina Display in 2015. Support was built into OS X 10.10.2 "Yosemite". The connector type is also used for Thunderbolt 3, but can also be used for USB 3.x signals without Thunderbolt, causing confusion among some users.About the Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter, Apple Inc. 2019-12-11. Apple's adoption of USB-C led to memes about the need for adapter dongles for physical compatibility with earlier USB devices.No Jack City... by Joshua Fruhlinger and Andrew Thompson, Ceros Originals. 2018-08-24.Apple, the company once mocked dongles, is in love with them now by Selene Kyle, The TechNews, Medium. 2016-11-07. However, the entire Mac product line has adopted this connector since then. The USB-C connector also supports USB4, introduced in 2020 with Apple devices based on the Apple M1 processor.
==Power delivery==
USB is specified to deliver power at various levels. This has become a common method of charging mobile devices. Standard USB 1.x and 2.0 ports can output up to 500 mA at 5 volts (2.5 watts) while USB 3.1 can output up to 3 amps.What are the Maximum Power Output and Data Transfer Rates for the USB Standards?, Cadence PCB Solutions. 2020-06-08. USB-C ports can output up to 5 amps at 20 volts (100 watts).
In October 2022, the passed legislation to require that new mobile devices sold in the European Union are to support USB-C as a common charging standard by the end of 2024.Apple will be forced to switch iPhone to USB-C by 2024 by David Price, Macworld. 2022-10-04.
===Vulnerability===
Though standard USB devices are supposed to negotiate power output levels, rogue devices known as "USB Killers" are known to exploit this by using s to absorb delivered power and then return it in 110 or 220 volt bursts until the host device or USB controller is destroyed. Some versions are commercially sold for the purpose of electrical "testing".The USB Killer, version 2.0 by Brian Benchoff, Hackaday. 2015-10-10.USB Killer now lets you fry most Lightning and USB-C devices for $55 by Sebastian Anthony, Ars Technica. 2017-02-17. However, graduate student Vishwanath Akuthota was jailed and fined for damaging or destroying over 50,000 in computer equipment (including iMacs) at the with such a USB Killer stick.Idiot admits destroying scores of college PCs using USB Killer gizmo, filming himself doing it by Kieren McCarthy, The Register. 2019-04-18.
==References==
==See also==
*Mini DisplayPort
==External links==
*USB Implementers Forum official website
**USB Document Library
*About USB on Mac computers at Apple Support
**About USB-C on Mac
**Adapters for the Thunderbolt 3 or USB-C port on your Mac or iPad Pro
**Use external storage devices with Mac
*USB & Firewire Capable Macs at EveryMac
*
*USB at the Beats by Dre Wiki
* and at Wikipedia
===Articles===
*Does My Apple Device Support USB 3.0? by Tom Nelson at Lifewire (2020-02-17)
*USB4 development complete, here’s what it means for Mac users by Chance Miller at 9to5Mac (2019-09-03)
Category:Acronyms
Category:Connectors
Category:Intel products