THE UNIVERSAL INTERFACE: USB STANDARDS AND PLUG TYPES

March 09, 2022

Whether it’s a camera, tablet, video game console, or external hard drive – USB is now the universal interface for connecting different devices and peripherals together, charging them, or transferring data. But USB interfaces are not created equal. Read on for an overview of the different standards and connector types.

When you want to hook up different devices or peripherals to transfer data, you typically do so via USB (which stands for Universal Serial Bus). We’re now at version 4.0 of the USB specification, but this doesn’t mean that all the preceding versions have been shelved. It’s not easy keeping track of the various USB standards and connector types, so it’s well worth taking a look at the different versions on offer before investing in a USB cable or adapter.

Brief look back: USB began life with teething problems

The whole idea behind USB was to bring simplicity to the chaos. Back in the ’90s, PCs had a host of different ports. It felt like you had to connect every peripheral to your computer with a different type of cable. So, a group of several companies, including IBM and Intel, set themselves the aim of creating a universal standard.

USB 1.0 was released in 1996. What looked promising, though, failed to catch on at the first attempt. That’s because the operating systems at the time, most notably Windows 95 and NT, didn’t support the new interface. USB 1.0 also had to contend with Apple’s Firewire alternative – something USB 1.0 literally couldn’t keep pace with due to its tortoise-like 12Mbit/s data transfer speed. Two years passed before USB 1.1 was released. Even though this revision offered a range of improvements, it wasn’t any faster. This meant that USB still had to sit out making its big breakthrough as a universal interface – something that didn’t happen until the early 2000s with the launch of USB 2.0.

Overview of current USB standards

USB 2.0: Even though it’s now over 20 years old, the USB 2.0 standard is still widely used today – including in charging cables for video game console controllers. That’s because in these scenarios you don’t need a faster, and therefore more expensive, version. USB 2.0’s supported data transfer speed maxes out at 480Mbit/s.

USB 3.0: The USB 3.0 standard hit the market in 2008. It provides for a data transfer speed of up to 5Gbit/s – a huge leap forward.

USB 3.1: At this point, things get a bit more complicated as there are two types of USB 3.1: Gen 1 and Gen 2. The former is nothing more than USB 3.0, which was simply renamed following the new version’s release in 2013. In the case of the latter, though, Gen 2 truly represents a significant improvement when it comes to data transfer speeds. At 10Gbit/s, it’s twice as fast as USB 3.0/USB 3.1 Gen 1.

USB 3.2: USB 3.2 was introduced in 2017. Once again, data transfer speeds doubled from 10 to 20Mbit/s. Likewise, the generations were renamed again. USB 3.1 Gen 1 (formerly USB 3.0) became USB 3.2 Gen 1, while USB 3.1 Gen 2 became USB 3.2 Gen 2. The newest, fastest version of this standard is called USB 3.2 Gen 2x2. Everything clear so far?

USB 4.0: USB4 was released in 2019, with the latest generation truly representing a break with the past. While it was easy to lose track of the previous versions due to their name changes and visually identical connectors, USB4 is in a class of its own. At 40Gbit/s, this USB standard offers double the data transfer speed of its direct predecessor. Plus, USB4 is the joint successor to USB 3.2 and Thunderbolt 3 – with USB4 based on the latter’s specification. KabelDirekt's USB 4.0 cables can also be used on Thunderbolt 3 and 4 ports.

Our USB 4.0 cables can also transmit video data in DisplayPort legacy mode - whether Full HD, 2× 4K or 8K.

Multiple standards, multiple connector types

There’s still a bit of ground still to cover on the topic of USB because USB connectors are also classified by the plug type. USB Type-A connectors are the most common type. You’ll find them everywhere, with practically every computer offering USB Type-A ports for you to hook up your mouse and keyboard. In this regard, you really need to keep in mind the standard that’s used. While you can basically plug a USB 2.0 cable into a USB 3.x port or a USB 3.x cable into a USB 2.0 port, you’ll only achieve the full speed if both the port and the cable support the same standard.

You’ll only find USB Type-B and Mini-B used on older devices and equipment. Some of you may still recall seeing USB Type-B on your older printer, while others will recognise the Mini-B version used on the PlayStation 3 controller. It’s still pretty common to find Micro-USB cables – which were considered the standard in the smartphone sector for a long time – in use today. These were initially followed by USB 3.0 Micro-B plugs, with an additional 5 pins stacked to the side, for external hard drives and other equipment where faster USB 3.0 data transfer speeds are required.

Meanwhile, the USB Type-C connection type has established itself to such an extent that USB 3.2 Gen 2x2 and USB4 are only supported by USB Type-C. There are no USB-A cables that support either of these specifications, which is why many PCs still have to do without USB4. That said, motherboards with suitable ports are already available.


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