USB Basics: Types, Speed and Why It Is So Popular

USB stands for Universal Serial Bus. USB standards are like blueprints that companies use to make cables and connectors. A unified standard ensures that your devices communicate easily.  It doesn’t matter which company made your devices.

USB cables were first introduced in 1996. At that time, you could not expect any old keyboard to work for your computer. So, a group of technology and electronics companies partnered to make a standard connection. This group is called the USB-IF and it still exists today.

Connector Types

USB connections are broken down into types A, B, and C. Type-A and Type-B are broken down further into mini-USB and micro-USB subcategories. The mini-A and mini-B were discontinued after the introduction of the micro-USB because the micro-USB was half the size of the mini variations but just as capable.


You have probably noticed that most desktops feature a lot of Type-A connections. They are flat and have a small colored portion called a receptacle, which is usually white, black, or blue. The Type-A connection is the most common USB connection for connecting peripherals to your computer. Keyboards, mice, external hard drives, thumb drives, and phone chargers all commonly use a Type-A connection.


Type-B connections have a square boxy shape. Larger devices, like printers or scanners, have Type-B ports. However, a computer no longer needs to be connected through a USB. Nowadays, some printers use a Type-C port, but most printers use WiFi or BlueTooth to connect to computers.

USB Types


Micro-USB, or micro-B, connections were the main connection used in the first smartphones. They also had an OTG function that allowed them to have an adapter that connected other USB connector types. Although micro-USB connections were extremely common, it was replaced by Type-C, and micro-B ports are mostly found in devices released before 2015.


The USB-IF plans to have the Type-C connection replace the other connections in time. The Type-C connector has far more connector pins than the other versions. These pins have a lot of different functions and it would be very complicated to explain all of them. Simply put, the extra pins allow the Type-C connection to transfer data and charge devices faster than the other types of connections. Eventually, all devices will be connected through a Type-C port, if they need to be connected at all.

To get additional information about USB connectors and their uses, click here

USB Speed Standards

All the different connector types have similar data transfer speeds. If you are concerned about data speeds you need to pay attention to which generation of USB you are using.

USB Speed

USB 1.0 & 1.1

USB 1.0 was released in 1996 and had data transfer speeds of 1.5Mbps. The USB 1.1 featured transfer speeds of 12Mbps. Both of these units feature white and later black receptacles in the USB-A port.

USB 2.0

USB connections using the 2.0 standards are usually black but can also be white. These USB connections can provide data transfer speeds of up to 480Mbps. The USB-IF called this feature High Speed.

USB 3.0, USB 3.1, & USB 3.2

The USB 3.0 standard was introduced in 2011. These USB connections are usually blue and feature speeds up to 5Gbps this was called SuperSpeed. Three years later the standards were updated to 3.1 standards which featured 10Gbs which was called SuperSpeed+. The USB 3.1 standards are generally teal-colored.  USB 3.2 is the last planned USB-A port and with a USB 3.2 port, you could transfer data at 20Gbps.

There are other colors that are featured in USB 3.x connections. For example, Orange and Red connections are called “Sleep-and-Charge” ports. They allow a phone, or other similar devices, to charge while plugged into a desktop even if the desktop is turned off.

If you want to read more about the differences between the USB 3.x connections, click here.


USB 4 is unique in many ways. The official name for this generation of USB is USB 4, without space in between the “B” and the “4.” However, people still generally type USB 4 when searching for information, so that is the way we will write it. There will only be Type-C versions of USB 4. Additionally, USB 4 connectors will also be compatible with Thunderbolt 3 and 4.

The USB 4 specifications can provide transfer speeds of up to 40Gbps. DisplayPort Alternate Mode will also be compatible with USB 4 for transmitting video. Previously, USB connections weren’t particularly useful for video transmission. This will allow USB 4 connections to transmit uncompressed 8K video.

Why Is USB So Common?

One Standard for Connectors

The initial goal of the USB-IF was to create a universal standard that all companies would follow. This would allow devices to easily communicate with each other despite having different manufacturers.

Thunderbolt cables can transmit information just as fast as USB cables, but they aren’t as commonplace. This is because, for the most part, only Apple computers have a port for Thunderbolt. This was the type of problem that the USB was created to avoid. Having a single connection standard ensures that your cables will still be useful if you get a new computer. 

USB so popular

Easy Configure

USB connections are often able to download the drivers they need automatically. This means that most of the time a person doesn’t need to do anything to use a USB. This is commonly referred to as “plug-and-play.”

Fast Transfer Rates

USB connections have consistently had the fastest data transfer rates compared to other standards. The major exception to this is that when Thunderbolt 3 was released, it was twice as fast as the USB 3.0 standard. USB 4 cables have matched the  40Gbps speed of Thunderbolt 4 which means Thunderbolt and USB now have the same data transfer speed.

Hot Swappable 

USB connections are all hot-swappable. This means that devices can be added or removed without turning off the computer. Most of the parts of your computer can only be replaced when your computer is turned off, like a hard drive or the CPU.

If you have ever used an external hard drive, then you’ll know that you can remove it without turning off your computer. The USB became popular because of its ability to hot-swap. Devices that have a USB connection are more user-friendly.

5 Frequently Asked Questions About USB

What Is the Function of USB OTG?

OTG stands for on-the-go. USB OTG is used to allow you to connect peripherals like printers and keyboards to your mobile devices like tablets and phones. USB OTG features a micro-USB. However, since Type-C has replaced micro-USB in most ways it is not as useful as it used to be. Most new devices don’t feature micro-USB ports.

USB Power Delivery?

The power delivery for USB connections depends on the connection type. The max power delivery for a micro USB is 60W and the max power delivery for a Type-C connection is 100W. The max wattage you can have while charging will also depend on the device and the charging brick.

Cell phones will not charge at a wattage for which they are not designed. So, even if you have a 100W Type-C cable and a 100W charging brick a cellphone will not charge at 100W. Not all USB connections are the same either. For instance, a Huawei charger will not charge a Google Pixel at all.

USB C Cable

Is USB 3.1 Backward Compatible?

USB cables are all backward compatible as long as they have the same connection type.  Still, it is important to remember that technology like USB only works as well as its weakest link.

If a USB 3.1 cable is plugged into a USB 2.0 port, you should expect USB 2.0 transfer speeds. The transfer speeds or charging speeds will be the same as the slowest element of the connection, whether that be the cable or port.

Is USB-C the Same as Thunderbolt?

USB-C and Thunderbolt are not the same. Intel developed a standard to compete with USB called Thunderbolt. If you are an Apple customer, you are familiar with these connections already.

Despite their similar size and shapes, Thunderbolt is not compatible with the USB 3.x. But, Thunderbolt 3 and 4 are compatible with USB 4. While USB 4 and Thunderbolt 4 are very similar, there are some differences.

Thunderbolt 3 and 4 connections are preferable over USB 4, particularly if you have an Intel processor. Both USB 4 and Thunderbolt 4 can transmit 8K uncompressed video. But, Thunderbolt 4 is able to dual-display 4K video as well.

Thunderbolt 4 is also guaranteed to send data at 40Gbps, but USB 4 has a version that transmits at 20Gbps. For most people, these features are not terribly important. Still, if they are important to you, you should consider this when shopping.

Is There a Maximum USB Cable Length?

Yes, after a certain distance the performance of your USB connection will suffer. The maximum distance for USB 3.x devices is not included in the specifications. But, if you want the cable to be longer than three meters, you should use a USB repeater. This will refresh the signal so it doesn’t lose its quality.

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