explained… Common types of USB
USB On-The-Go (OTG) devices got the even more esoteric Micro-AB socket, which removed the corner chamfers to accommodate both USB 3 Micro-B and the largely mythical Micro-A. OTG allowed role-swaps between computer and device, so a phone could supply data to and draw power from a Mac as an accessory, but then connect to a camera or keyboard as a host.
USB 3.0 killed FireWire, but its new rival was Thunderbolt, an Apple-influenced copper version of technology first demonstrated by Intel over optical fibre. After the USB Implementers Forum (USB-IF) declined to back it, Thunderbolt was shoehorned into Mini DisplayPort instead, creating a 10Gbps multi-purpose connector.
USB 3.1, arriving in 2014, matched Thunderbolt’s speed, but only in Gen 2 ports, branded SuperSpeed+. Thunderbolt retained the advantage of daisy-chaining, allowing up to six devices per port, versus USB’s one. Mobile hone Smaller devices remained resistant to standardisation, and in 2003 the iPod switched from FireWire not to a USB port, but Apple’s 30-pin Dock connector. Even so, the interface was USB-compatible, with a Type-A plug on the other end of the cable.
The same arrangement was used for the iPhone in 2007, but when it began to feel out of scale with modern devices, Apple replaced it (in 2012) with Lightning: as compact as Micro-B, yet reversible and with a simpler plug, like the tab in USB ports, and a hollow socket.
USB Type-C emerged from the USB-IF (now including Apple) two years later, similarly compact and reversible – finally scotching the joke that there were four ways to insert a USB plug, three of them wrong – but retaining the form of a tab inside a receptacle, with a hollow plug fitting concentrically. Most Type-C ports are USB 3.1 Gen 1 or 2, but just to complicate matters, Thunderbolt 3 jumped formats and became a superset of USB Type-C.
Every Thunderbolt 3 port will work with any USB Type-C cable and device, but not every USB Type-C port supports Thunderbolt 3 devices. All Thunderbolt 3 cables work with USB Type-C devices, and good-quality USB Type-C cables will work for Thunderbolt 3 devices, but you’ll only get Thunderbolt 3’s maximum 40Gbps with a 0.5m or shorter cable, unless you buy an ‘active’ Thunderbolt 3 cable with electronics that boost the signal.
40Gbps should satisfy most of us for a while, but with Apple now sitting on the USB-IF board, what comes next will be interesting.