What are the Different Versions of USB and How do They Work?

USB (Universal Serial Bus) ports are the small rectangular holes that can be found on either the front or back of a computer. They are used for connecting a wide variety of peripheral devices to the computer: digital cameras, MP3 players, keyboards, external drives, and printers. Over the past decade, they've become a standard way to connect devices to both PCs and Macs, so that every modern computer has USB ports. Of course, as with any other technology, there are constant innovations being made, and multiple versions of the USB port now exist.

The Basics: How Does USB Work? And What Is a USB Hub?

A USB connector basically consists of a rectangular plug and a cable with four wires inside. Two of the wires carry power from the main computer to the device. The other two wires carry data by using a binary system (the ones and zeros being indicated by differences in voltage between the two wires).

Although nearly every computer has multiple USB ports (which are the slots that the connectors plug into), many people use hubs to expand their computers’ USB capabilities. A USB hub works by functioning as a USB port multiplier. It has several ports and is able to funnel information from any devices plugged into those ports to the computer via one connector. A USB hub can be either bus-powered (which means that it gets its power from the computer) or self-powered (which means that it gets its power from an external source, like a battery or electrical outlet).

Of course, before USB hubs became commonplace, USB technology itself had to become commonplace.

USB 1.1: Where It All Began

The original version of USB technology, USB 1.1 (USB 1.0 didn't receive a wide release), was introduced in 1998. Before this time, whenever a new device (printer, external hard drive, keyboard, mouse) needed to be plugged into a computer, another port needed to be added to the main computer to accommodate the new plug. USB was developed as a joint project of several major computer companies. It was a type of connection designed to make it easier to add new devices to computer systems. In addition, they wanted to develop a way to connect devices that didn't require the user to re-start the computer every time a device was added or removed.

USB was not an immediate success. But over time, as computers became more prominent in both homes and offices, more users saw the advantages of a standardized connector. Of course, by the time USB 1.1 was widely accepted, it was time to improve it.

USB: It's as simple as 1.0, 2.0, 3.0!

USB 2.0: Pretty Much the Same as USB 1.1, Only Better

USB 2.0 was released in 2000. Its most obvious advantage over USB 1.1 was that it had a much faster processing speed. USB 1.1 could process data between 1.5 megabits per second (Mbit/s) and 12 megabits per second (making it twenty times faster than the system it had replaced). USB 2.0, by contrast, could process up to 480 Mbit/s.

Of course, one of the keys to the success of USB 2.0 was that it was compatible with USB 1.1 devices (and vice versa). Computer users didn't have to throw out USB 1.1 devices once they picked up a computer with USB 2.0 ports. Conversely, they didn't have to worry about USB 2.0 devices not being able to function with USB 1.1 computers. Of course, USB 1.1 devices wouldn't run any more quickly if hooked to a USB 2.0 computer and USB 2.0 devices would actually run more slowly when hooked to a USB 1.1 computer, but they were still compatible.

USB 3.0 and USB 3.1

By the time USB 3.0 was released, USB connectors were an industry standard for both Mac and PC systems. Like USB 2.0, the most obvious innovation of USB 3.0 was an increase in processing speed. Released in 2008, USB 3.0 had a processing speed of 5 gigabits per second (Gbit/s) or 5,120 megabits (1 gigabit = 1024 megabits) per second. USB 3.1, released in 2015, doubled this processing speed to 10 Gbit/s. As USB 3.1 became more popular, USB 3.0 began to be referred to as USB 3.1 Gen 1 (with USB 3.1 being referred to USB 3.1 Gen 2).

Types A, B, and C

USB is a technology that allows connections to be made between computers and devices. Every new version of USB has been reverse compatible, allowing a wide variety of devices to connect to a wide variety of computers. However, in addition to updates to the technology, there are also different shapes and styles of USB ports.

The plug and port connection that has become standard for most computers is known as Type A. Desktop and laptop computers with a USB port (whether it's a Mac or a PC or a 1.1, 2.0, 3.0, or 3.1) will generally have a Type A port. The devices that connect to the computer, on the other hand, have a variety of B ports (standard-B, mini-B, micro-B, micro-B USB 3.0, standard-B USB 3.0).

The A port is the same, but the B port is different. This is why you need a different cord to connect your phone, your printer, and your digital camera to your computer, even though all of them would plug into the same USB port on the computer.

The Type C port is an attempt to standardize USB connections on both devices and computers. The aim is to eventually have a Type C port on new computers and new devices. In the long-term, this would mean that you'd only need one cord to connect any device to your computer. In addition, Type A and Type B ports are designed with the idea that power would only travel one way (from the Type A port on the computer to the Type B port on the device). With a Type C connection, power would be able to travel either way. While this could allow a computer to charge itself off a phone or camera, the more practical application is that power banks can be designed with a Type C port, so they'll be able to plug into the computer the same as any other device; currently, most computers still have a separate port set aside for power sources.

The Type C port is an attempt to standardize USB connections on both devices and computers. The aim is to eventually have a Type C port on new computers and new devices. In the long-term, this would mean that you'd only need one cord to connect any device to your computer. In addition, Type A and Type B ports are designed with the idea that power would only travel one way (from the Type A port on the computer to the Type B port on the device). With a Type C connection, power would be able to travel either way. While this could allow a computer to charge itself off a phone or camera, the more practical application is that power banks can be designed with a Type C port, so that they'll be able to plug into the computer the same as any other device; currently, most computers still have a separate port set aside for power sources.

Should the Type C port system become a standard (and it has been gaining in popularity), then the future of computers will do away with the various adaptor cords. Eventually, computers and devices may simply have a series of Type C USB ports, with no need for any other type of port. We'll be able to download data, connect to printers, and power our computers with the same cords.

Plus, connecting devices like smart phones and digital cameras to one another will become much simpler and not require computers as go-betweens. Once such a standard is reached, USB 4.0, 5.0, and beyond will be truly universal!