What is USB (Universal Serial Bus)?

USB (Universal Serial Bus)

USB stands for Universal Serial Bus, which sounds impressive and complicated but doesn’t tell you much about what USB is.

A more accurate description of the technology would say that USB is a standard—a universal standard connecting computers and devices.

The power behind those connections comes from different technologies.

Still, the real benefit of the system is that devices are interoperable without any special software or drivers being installed on either end of the connection.

The specifics of how data gets transferred over a USB cable vary based on its speed (and, therefore, its version number), but all versions work by sending data as a continuous series of electronic pulses along a single pathway.

This type of data transfer method, where information travels in one direction along a single channel, is called serial communication—hence “serial bus” in our definition above.

In addition to carrying data between two devices, USB can send power across that connection, too.

For example, charging your phone or powering an external hard drive, so you don’t have to worry about batteries running out at an inconvenient time (or worry about whether your wireless router will let you connect them).

What are USB Devices?

USB devices are the things you plug into the USB port, e.g., a scanner, digital camera, mouse, keyboard or touchscreen, etc.

You would plug in a flash drive if you want to transfer files from one computer to another via that device.

USB devices can be used for many different purposes, including transferring data between computers and uploading pictures from your digital camera.

How Do USB Devices Work?

You can plug any USB device into a computer or other USB-enabled device.

You can also connect multiple USB devices through a USB hub.

USB devices have four wires used in both connections: two wires for power and two wires for data.

The power cables are responsible for charging the device. In contrast, the data cables allow information to be sent between the computer and the device.

USB Port vs. USB Device

What is a USB Port?

Before answering this question, let’s differentiate between a USB port and a USB device. It’s easy to confuse these two things, so I want to ensure you don’t get them mixed up!

The USB port is always on the computer itself. This means that it will be there even if you haven’t plugged any devices into your PC yet—the port is part of the computer and can’t be removed from it.

What is a USB Device?

What is a USB Device?

On the other hand, a USB device can be removed from your computer by simply unplugging it from the port.

Examples of USB devices people commonly plug into their PCs are mice and keyboards (yes, even wireless ones), printers, scanners, and external hard drives.

Types of USB

Types of USB


Most USB ports on computers, laptops, smartphones, and tablets are rectangular Type-A. You typically use it to connect a peripheral device like a camera or external hard drive to your computer.

You’ll also see a Type-A port on game consoles and DVD players. Some printers have a Type-A port for connecting external flash drives or other peripherals.


You might have used a USB B port if you’ve ever tried to connect a printer or scanner to your computer. The ports are square and feature two side-by-side USB connections.

You’ll often see the word printer or scanner on these devices since they’re frequently used for printers or scanners!

Mini USB

Let’s talk about Mini USB ports. Before the micro USB standard was created, these were the classic port that you find on older phones and cameras. More modern alternatives are slowly phasing out the mini USB port.

However, it’s still in use on some devices—and is also included on almost every Arduino (a popular programmable micro-controller).

Mini USB has a slightly smaller connector than a regular old USB A or B but comes in two flavors: one with five pins and one with four pins (power and ground only). This version is sometimes called mini-B.

The big difference between the two ports?

Mini-A is not reversible. It’ll only fit into your computer or charger one way; One upside to this design is that it makes it easy to tell which way you’re supposed to plug it in.

Micro USB

Micro USB connectors, which primarily support smartphones and tablets, are designed for smaller devices. They are also faster than Mini USB connectors – they can transfer data at 480 Mbps, compared to Mini USB’s 12 Mbps.

Like their larger cousins, Micro USB connectors are designed to be reversible and make it easy to plug in a device without switching the cable over and trying again.


The most notable feature of USB-C is that it has a reversible connector. This was a necessity in the modern world, where people carry several different devices that all need to be charged and connected to each other.

Before USB-C, you constantly plugged your charging cable upside down and then fiddled around with it until you got it right. USB-A connections were also notorious for being slow at data transfer—it would take forever to sync your phone with your computer.

Plus, if you had a device that needed a lot of power—like an external hard drive—you had to make sure the port was using enough electricity, or the device wouldn’t work correctly.

USB-C fixes all three of those problems. It can transfer data much more quickly than USB-A could ever dream of doing, so syncing your phone should take less time now (and don’t even get me started on how much longer it used to take when we didn’t have USB—you’d have to use serial cables!).

More importantly, though, the reversible connector means no more trying every angle before you get it right!

And finally: The faster speed also means this port can provide power up to 100 watts at 20 volts. That’s enough energy for something as big as an external monitor or a laptop!


The newest USB port on the market is USB 3. This USB port, also known as SuperSpeed USB, takes advantage of the quicker transfer rates available in USB 2.0 and can transfer data at speeds up to 5 Gbps.

USB 3 ports are also backward compatible.

A device with a USB 3 port will be able to communicate with any other device using either USB 1 or 2 ports, but the device using the older technology will not be able to take advantage of the additional speed offered by a device using a SuperSpeed USB port.


So, what have we learned?

A USB or Universal Serial Bus cable is a data connection port that has replaced many older ways of connecting to printers, scanners, and other devices.

There are several kinds of USB cables available for different purposes and devices. While the original USB cable was two meters long, some newer versions can be longer. The original version used to connect only with printers and scanners.

However, you can now use them to connect cell phones to computers and mice, and speakers. Some even allow you to charge your phone from your computer or laptop. There are many new uses for these cables being developed all the time.

If you’re considering purchasing a printer, scanner, or other devices, before you do so, make sure it’s compatible with one of these cables so you’ll be able to connect it quickly when it arrives or save yourself some money by not having to purchase an adapter separately!

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