The Universal Serial Bus (USB) port is perhaps the most commonly used and easily recognizable PC connectivity standard found on modern hardware. But as universal as the rectangular port and its various data transfer standards are, things have changed with the introduction of USB Type-C.
The smaller, reversible, oval Type-C connector is positioned to become the go-to port for both commercial and industrial computers, making the dream of a legitimately universal connection standard, at least in part, a reality. But like any tech change, there’s plenty of room for confusion with USB Type-C. Clarity isn’t helped by the USB 3.0/3.1/3.2 and now USB4 transfer standards. So what exactly is USB Type-C? How is it better than its predecessors, Type-A, and Type-B?
Watch our Tech Edge video on the topic, or keep reading to find out.
What is USB Type-A?
The most common and familiar USB connector shape is USB Type-A, which is currently used on the vast majority of computer equipment and peripherals. It is also used on many other devices, including those that utilize its Mini-A and Micro-A variants (see image above). Gaining popularity in the mid 90’s, standard USB Type-A connectors are rectangular and have a distinct top and bottom. This requires them to be oriented properly in order to be plugged in.
What is USB Type-B?
The more square shaped USB Type-B is somewhat less common but is electrically identical to USB Type-A connectors. USB Type-B connectors are frequently used on printers, though they can also be found on some monitors and USB hubs. The Mini-B and Micro-B connectors, like their Type-A counterparts, are found on a wide range of electronics, from tablets and handheld GPS devices to cell phones.
What Is USB Type-C?
Type-C refers to the physical shape of the newest USB connector. (The USB Type-C connector shouldn’t be confused with the USB 3.1 or USB 3.2 standards.).
The USB Type-C connector is smaller than both Type-A and Type-B, oval-shaped, symmetrical, and reversible, meaning there is no “wrong way” to plug it in. This eliminates one of the most common complaints about USB Type-A. This newest USB connector is intended to replace the other existing USB form factors and provide a future-proof, fully-featured option for hardware designers to standardize on. USB Type-C ports are becoming more and more common on mobile devices and consumer hardware. On the other hand, the industrial PC (IPC) market is just beginning to dabble with integrating USB Type-C ports into the latest generation of commercial devices.
Finally, we should note that while USB Type-A and USB Type-B have traditionally been written using the word “type” as shown, USB Type-C is increasingly being written as simply USB-C.
It’s also important to note that the USB Type-C charging port will be mandated in the EU starting in 2024. This new law is a part of a broader EU effort to make products more sustainable, to reduce electronic waste, and make consumers’ lives easier. The first stage applies to small electronics like cell phones, digital cameras, and more. Medium electronics, such as laptops, have until 2026 to implement USB-C for charging.
Breaking Down USB Data Transfer Rates
It’s important to make the distinction between a given USB port form factor (like Type-A or Type-C) and the data transfer rates and power delivery available over that port. The standards that dictate the performance of USB are instead expressed as a numerical value, like USB 2.0, 3.1, 3.2 or 4.
The USB 1.0 specification (introduced in 1996) offered a maximum data transfer rate of 12 Mbps (Megabits per second). USB 2.0 maxes out at 480Mbps. USB 3.0, 3.1 and 3.2 are a little more confusing. What is the difference between USB 3.2 Gen 1 vs Gen 2 and USB 3.2 Gen 2×2? What about USB4? Let’s break it down:
USB 3.2 Gen 1 used to be called USB 3.0 and offers a transfer rate of 5 Gbps, which is about 10 times faster than the USB 2.0 standard.
USB 3.2 Gen 2, released in July 2013, used to be called USB 3.1 and offers a transfer rate of 10 Gbps over the existing USB-A and USB-C connectors – twice the rate of USB 3.2 Gen 1.
USB 3.2 Gen 2×2, released in September 2017, is available only for USB Type-C connectors using two-lane operation. It offers 20 Gbps transfer speeds.
USB4 was announced in March 2019. It
leverages the Thunderbolt 3 protocol and offers transfer speeds of 40 Gbps. (Note that the correct specification name is USB4
as defined by the USB developers. It is often identified as
USB 4 with a space.)
USB 3.2 Language Usage Guidelines
USB Implementers Forum (USB-IF), the group that oversees USB standards development, has made efforts to introduce more human-friendly terms for these varying data transfer standards. The USB-IF calls USB 2.0 USB Hi-Speed. The version 3 variations are referred to as USB SuperSpeed 5Gbps, USB SuperSpeed 10Gbps, and USB SuperSpeed 20Gbps. It should also be noted that when the 3rd generation standards were announced, many USB 3.0 and USB 3.1 products were already available. If a port is labeled as USB 3.0, you can assume that data transfer speeds will top out at 5 Gbps.
USB A – Visual Differences
Transfer speed differences are very important to understand when you’re connecting devices via USB. Since there is such a large jump in speed capabilities between generations, some manufacturers currently distinguish Type-A USB 3.2 Gen 1 ports with blue inserts. That is particularly true when they appear on the same device as USB 2.0 ports. Alternatively, the USB SuperSpeed logo or its “SS” abbreviation may be used to identify USB 3.2 ports, particularly when all USB ports on a given device are USB 3.2 (as on the CL100).
It should be noted, however, that while the data transfer rates of USB 3.2 Gen 2 and Gen 2×2 are impressive, many devices aren’t yet capable of reading or writing at those speeds. Actual speeds will be based on the host and destination devices as well as the capabilities of the USB cable being used (which we’ll dive into shortly).
The Power Capabilities of USB 3.2
Even early versions of the USB standard were designed to power connected peripherals, and as the technology has matured, the charging and powering capabilities of USB have also evolved. Both USB 3.2 Gen 1 and Gen 2 support the USB Power Delivery Specification (USB PD), with Gen 2 offering up to 20 volts of power at 5 amps for a potential total of 100 watts through supported hardware. This is a major leap forward from the previous USB 2.0 standard which was capable of providing 2.5 watts of power.
USB and Industrial Computers
Again, while USB Type-C and USB 3.2 are sometimes used interchangeably, they are not one in the same. Both USB Type-A and USB Type-C connectors are used to facilitate USB 3.2 Gen 1 and Gen 2 connections, and USB Type-C is also used to facilitate the USB 3.2 Gen 2×2 connection.
We expect that the majority of industrial computers will continue to feature both USB Type-A and USB Type-C connectors as well as support for multiple data transfer speeds and power handling for the foreseeable future. It rests on manufacturers to appropriately label USB ports going forward to help avoid confusion.
USB Cable Compatibility & Capabilities
One final variable to consider when trying to utilize USB 3.2 transfer rates and power output to their fullest potential is the USB cable. In the case of data transfer, all three parts of the data equation have to be compatible with transfer rate. That includes the source (your computer), the USB cable, and the destination device (a hard drive or other system). For example, cables that support USB 3.2 Gen 2 and transfer data at up to 10 Gbit/s are constructed with anywhere between 15 and 18 wires. USB 2.0 cables, on the other hand, contain only 5 or 6 wires.
Cables with More Wires Offer More Features
The additional wires in USB 3.2 cables enable ultra fast data transfer as well as the dramatic increase in power output capabilities. They also provide additional features. For example, USB 3.2 connections can also offer DisplayPort capabilities, provided the hardware and cable are compatible. This makes 4k video output, data transfer, power output, and even power input possible over a single cable. With these new capabilities, creating a new standard port (USB Type-C) means that at some point soon, the vast majority of connections could require significantly fewer cables.
Conclusion: What You Need to Know About USB Type-C and USB 3.1 and 3.2
The launch of USB Type-C and the corresponding release of USB 3.1 Gen 2 (now calledUSB 3.2) offer some very exciting possibilities for today’s computing devices. However, they’ve also created their fair share of confusion. Here are the key takeaways:
USB Type-C is NOT the same thing as USB 3.2
USB Type-C ONLY describes the physical connector
USB 3.2 ONLY describes the capabilities of the port
A Type-C connector does not automatically indicate that a USB port will support USB 3.2 Gen 2 or USB 3.2 Gen 2×2 data transfer speeds (10 Gbps or 20 Gbps)
The term “USB 3.1” or “USB 3.2”
may
be used to describe ports that support either 5 Gbps data transfer (USB 3.2 Gen 1) or 10 Gbps data transfer (USB 3.2 Gen 2)
The appropriate cables and compatible hardware are required to maximize the data transfer speeds, power output, and additional features (like 4k video)
USB 3.2 is fully backwards compatible with previous versions, but USB Type-C is not strictly backwards compatible due to the new port form factor, although adapters are readily available
We completely agree that this is confusing! If you still have questions, or would like to chat with one of our Solution Specialists about an upcoming project involving any of the USB standards or connectors covered here, don’t hesitate to reach out.
This blog was originally posted on July 21st, 2020. It was updated for content on April 19th, 2022.
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