From Apple’s Thunderbolt page:
“Thunderbolt 3 offers a connection with state-of-the-art speed and versatility. Delivering twice the bandwidth of Thunderbolt 2, it consolidates data transfer, video output, and charging in a single, compact connector. And with the integration of USB-C, convenience is added to the speed of Thunderbolt to create a truly universal port.”
So, that’s Thunderbolt 3… and Thunderbolt 2… and USB-C? Huh?
Let’s break down some of these interfaces, starting with their shapes.
USB’s Type A connector is rectangular, 15.7mm wide by 7.5mm tall. It’s often difficult to tell which way is “up,” so it’s sometimes necessary to flip the plug to connect it correctly.
Universal Serial Bus (USB), first released in January 1996.
Many USB 3 plugs use color coding to distinguish them from older, slower 2.0 cables. Keep an eye out for a blue tip.
This connector is narrower than USB-A, at 7.5mm wide by 4.6mm tall. It has beveled edges at the bottom of the plug, making it a little easier to eyeball which way it needs to go into the port.
In addition to the plug’s shape, markings on the connector may indicate which standard the cable in question follows: Apple’s Mini DisplayPort; or Thunderbolt, co-developed by Intel and Apple. The easiest way to tell a Thunderbolt cable from a Mini DisplayPort cable is to look for the “bolt” symbol on the plug:
A Mini DisplayPort plug may not have any markings on it, or it may have the “display” logo on the plug:
Mini DisplayPort, first released in 2008; and Thunderbolt, first released in 2011.
Apple embraced Mini DisplayPort as their monitor connection of choice, starting with their late 2008 notebooks, and then into their 2009 desktops. The only latecomer of their notebooks was the 17″ MacBook Pro, which featured Mini DisplayPort in early 2009.
Thunderbolt, which provided the monitor connection as well as high-speed data rates for hard drives and multi-port docks, replaced Mini DisplayPort on Macs in early 2011. By late 2013, it was standard on all Macs except the 2015 MacBook (more on that model in a bit).
A computer’s Thunderbolt port is backward-compatible with Mini DisplayPort cables and displays, but not vice versa. For example, Apple’s now-retired 27″ LED Cinema Display (produced from 2010 to 2013) will work in either Mini DisplayPorts or Thunderbolt ports, but their almost identical-looking Thunderbolt Display (2011-2016) will only work in a Thunderbolt port.
Featuring twice the speed of its predecessor, Thunderbolt 2 came standard on the late 13” and 15” 2013 MacBook Pro Retina models; the late 2013 Mac Pro cylinder; the late 2014 Mac mini; and the 11” and 13” Early 2015 MacBook Air. The MacBook has never included Thunderbolt (again, more on that model in a moment).
So at this point, around 2013, we have two plug shapes, with two formats now capable of delivering 10 Gigabits per second, or more. USB 3 was backward-compatible with its previous versions, and Thunderbolt 2 was backward-compatible with Thunderbolt 1 and Mini DisplayPort.
And then, in 2014, the shape of things changed, yet again. Enter USB Type C.
NOTE: For the purposes of this post, I’m skipping past USB Type B, which is just the house-shaped plug often found at the other end of a standard USB cable. It’s the end that plugs into a printer, a desktop hard drive, or other peripherals.
This is the dream, realized. A symmetrical plug, with no “wrong” way to plug it in.
Apple did beat USB to the punch in 2012 with their proprietary, symmetrical Lightning connector, but that was only utilized by the iPods, iPads, and iPhone of the time, onward. It was never featured as an interface on any of Apple’s desktop or notebook computers.
And yes, “Thunderbolt” and “Lightning” is a confusing coincidence.
USB Type C is actually quite similar to Lightning at first glance. USB-C is 8.3mm wide by 2.5mm tall, and Lightning measures 6.7mm wide by 1.5mm tall.
Apple hasn’t indicated any plans yet to replace Lightning with USB-C.
USB-C first came on the scene in 2014, in the Nokia N1 tablet, initially released in China.
It provides the full data rates of USB 3.1 standard (SuperSpeed USB 10 Gbps), as well as the capability to charge mobile devices such as smartphones and tablets (such as the aforementioned Nokia N1).
While Apple sticks with Lightning for their iPhones and iPads for now, USB-C is becoming the go-to charging and data port for Android mobile devices from brands like LG, HTC, Asus, Lenovo; and it was the interface for the late, lamented, combustible Samsung Galaxy Note7 (but the general consensus is that the charging cable was not responsible for the fires: https://www.cnet.com/news/why-is-samsung-galaxy-note-7-exploding-overheating/)
Apple may be sticking to Lightning for iPhone and iPad for now, but they took a leap in April 2015 to USB-C as the sole port in their resurrected MacBook line.
It was the first Mac to use the same port for data and for charging—a controversial move, as this meant no other peripherals could be plugged in while the computer was charging…unless users connected an adapter, such as the USB-C Digital AV Multiport Adapter (sold separately, of course).
Intel launched Thunderbolt 3 in June 2015, incorporating the increasingly popular USB-C plug shape, and retiring the old “Mini DisplayPort” connector.
Much like how Thunderbolt 1 & 2 were backward-compatible with Mini DisplayPort; and how USB 3 Type A was backward-compatible with USB 2 and 1, Thunderbolt 3 is backward-compatible with USB-C devices (but not vice-versa).
So USB and Thunderbolt have now converged. The upshot is, all your USB and Thunderbolt devices will still work if you get a computer with Thunderbolt 3 ports… you’ll just have to buy new cables or adapters to plug them in. Alternatively, you could invest in a dock, such as this 13-port solution from OWC. It’s pricey, but it allows you to use your current peripherals and their own cables, instead of having to adapt each one for the new port shape.
Because this is the shape of things, now… at least, until a new standard comes out.