Ports are more confusing than they should be. With all the different USB standards out there, it’s easy to get overwhelmed by the number of options. USB-A and USB-C are the two most common forms of USB, and knowing the differences between the two is essential for understanding what all your devices and peripherals can do.
What is USB-A?
USB Type-A connections refer to the physical design of the USB port. Every USB connection comprises a port in the host device, a connecting cable, and a receptor device. USB-A is a traditional USB host port design and one of the easiest to recognize on devices.
It’s a horizontal port with the bottom portion dedicated to pin connectors. This arrangement creates the infamous, one-sided USB connection that only works with the cable perfectly inserted, no matter how many times you have to try.
Interestingly, there is no USB-B host port. The USB-B design is the receptor port on the device you are connecting to the host computer. Type B connections are also easy to recognize because of their square shape with rounded corners on one side, almost like the shape of a tiny house. USB-B is mainly for external peripherals, with a USB-A connection on one end and a USB-B connection. There are USB-B to USB-B cables, but they’re rarely used.
Note that there are also subsets of this design, like USB Mini-A and USB Micro-A, with different port designs, but these aren’t as important for our current discussion.
What is USB-C, and how does it differ?
USB-C is a newer port design officially announced in 2014, although it took several years for the ports to reach widespread consumer devices, as we see today. Designed to solve many of the old USB-A port problems, USB-C was an entirely new type of USB port. Critical features of USB-C include:
- A slimmer design that fits into a port no matter which direction it’s flipped, designed to replace A, B, mini, and micro connections all at once.
- A 100-watt, 20-volt connection is far more powerful than the older port and can handily power even larger devices.
- Potential for much higher transfer speeds than USB-A.
- Support for power delivery to charge up devices on either end (with the right cables) and charge larger devices.
- Support for video delivery at much higher quality, including transmitting 4K video to a screen.
- Support for alternate modes that allow for lots of different adapters for specific connections like HDMI or VG — or older types of USB connections.
- Potential compatibility with Thunderbolt 3 connections means a USB-C port can double as a Thunderbolt 3 port with extra hardware.
So, USB-C is a better connection?
With the right data standard (see below), USB-C is much faster and more versatile than USB-A. In time, you can expect USB-C connections to replace all older USB-A connections and other ports. This switchover will, however, probably take years.
For now, USB-A shows up alongside USB-C in many computers, primarily to deal with compatibility issues. People still have older smartphones, beloved controllers, receivers, TVs, keyboards, and many peripherals that require a USB-A/B connection.
Most people don’t want to buy an adapter to make USB-C backward-compatible with all their stuff. As the use of these older devices fades, USB-C will become the go-to port that everyone knows to look for — and we already see this happening in some sectors.
Where does USB 3.1 fit into this?
USB 3.0 or 3.1 refers to specific data protocols for USB connections: Instead of describing the physical port, this refers to the data formats the port can handle. A notable change came with USB 3.0, which required a modification of the USB-A and USB-B designs to gain more capabilities and faster speeds. USB-A cables that support USB 3.0 and above come with a blue pin protector instead of the standard gray one.
USB 3.1 is typically divided into USB 3.1 Gen 1 and USB 3.1 Gen 2 and offers many of the data improvements that USB-C supports, including speeds up to 10Gbps and new charging capabilities.
To make matters more confusing, USB-A and USB-C ports can support various standards, anywhere from USB 2.0 to USB 3.1 Gen 2. Even worse, not everyone uses the same names for these protocols, so USB 3.1 Gen 1 is also called USB 3.0. The goods news is that USB 3.1 is backward-compatible with all other USB connections, although USB-C ports may require an adapter. You also must make sure that your USB cables and devices support 3.1 data capabilities when possible.
Have a headache yet? Let’s simplify things with a few crucial points to remember:
- USB-A and USB-C can have various data standards, up to USB 3.1, which dictates their data capabilities.
- USB 3.1 is backward-compatible with other standards, although it may require adapters, making it an excellent standard to look for.
- Only a USB-C connection can use the full potential of USB 3.1 Gen 2.
- Cables and devices must also support the USB data standard — if you get a port with USB 3.1, your cable and your connected device must also support 3.1 to take full advantage of it.
- Buckle up: USB 3.2 standards are already well on their way and will make things even more confusing, with several varieties and each with their own name.