A reader wanted some help understanding types of USB :
“As I start shopping to replace my aging desktop with a laptop, I find I don’t know enough about USB ports. I hear about USB 1, USB 2, USB 3, and now USB 3.1. I understand the newer ones are faster.
Are they compatible? Do you need special ports for the newer services? special software? And what really is the difference between them? If you move to the newer ones, do you have to pitch the older ones? Any enlightenment would be appreciated!”
USB stands for Universal Serial Bus. The standard was invented to come up with one way to connect devices to computers instead of each type of device requiring a different type of port. USB connections are capable of not only transferring data, but powering and charging devices.
USB 1, 2, and 3 connections look pretty much identical externally. If you look closely, though, the color of plastic visible inside the device lets you know which generation it is.
USB 1 is usually white, 2 is black, 3 is blue.
USB 1 made its appearance 23 years ago followed by USB 2 in 2000. USB 2 is 40 times faster than USB 1. USB 2 devices were backward compatible with USB 1 ports, but you didn’t get the same speed.
USB 3 and then 3.1 in 2014, and 3.2 in 2017.  To compare speed rates, USB 1 has a transfer rate of 480 Mb per second while USB 3.2 can transfer up to 20 GB per second.  USB 3 is also capable of powering larger devices.
You can use a USB 3 device in a USB 3 port and a USB 2 device in a USB 3 port, but you won’t see the speed increase unless both devices are USB 3.
USB ports in your PC or plug are normally the type A connector that you see on a standard flash drive. The plugs on the other ends of cables have come in a variety of shapes over the years to fit cameras, printers, phones, and other peripherals. Mini-A, Mini-B, and Micro-A have fallen by the wayside with USB 3. You’ll normally see an A connection, the squarish B connection that often connects to audio devices and printers, and the Micro-B which is usually for phones and other small devices.
usb-connector chart.jpg
With USB 3.1 and 3.2, you will sometimes see the USB C connection. This an attempt to standardize the connections for all devices. USB C cables can transmit large quantities of data and are also capable of transmitting enough power to charge a laptop, doing away with the need for proprietary charging plugs. USB is compatible with USB 3.0 ports.  In many ways, USB C is attempting to do what USB was created for in the first place, come up with a truly universal port and plug.
If your new computer only offers a USB C connection, you will need a hub to use USB A devices and drives.  However, if having a super-light easily portable computer is a priority, it might be worth it. For a desktop, I’d want several USB 3.1 or 3.2 ports.  These ports should be compatible with USB 3 and 2 cables, drives, and devices. (Though if your devices are as old as USB 2, there’s no guarantee they’ll work. And remember, external drives and thumb drives don’t last forever. If you have one that’s 15 years old, it’s probably time to transfer your data to something newer or the cloud before it gives up the ghost).
And heads up, USB 4 is coming our way, you’ll likely see the first products at the end of 2020 and it will use the USB C connector. But don’t worry, USB 4 will be compatible with USB 3.