USB

Universal Serial Bus (USB) is an industry standard that establishes specifications for cables and connectors and protocols for connection, communication and power supply (interfacing) between computers and peripherals.

The USB specification was co-created at Intel by Ajay Bhatt in collaboration with Compaq, DEC, IBM, Microsoft, NEC, and Nortel. First released as USB 1.0 in January 1996, the USB standards are currently maintained by the USB Implementers Forum (USB-IF). There have been four generations of USB specifications: USB 1.x, USB 2.0, USB 3.x and USB4.

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. 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 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.

USB-C
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. Apple's adoption of USB-C led to memes about the need for adapter dongles for physical compatibility with earlier USB devices.

USB4
USB4 is based on Thunderbolt 3, but has not yet been released in a product from Apple.

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)