USB – Universal Serial Bus

A USB port is a standard cable connection interface for personal computers and consumer electronics devices.

USB ports allow USB devices to be connected to each other with and transfer digital data over USB cables. They can also supply electric power across the cable to devices that need it.

Who invented USB?

The development of USB began in 1994.

Compaq, IBM, DEC, Intel, Microsoft, NEC, and Nortel joined hands together for the development of USB

Ajay Bhatt co-invented USB in 1995 who was the leader of the team which was formed by these seven companies.

One day he was sick of printer plugs as they were not easy to handle and decided to invent something which would be easy to use. Hence he and his team came up with the invention of USB while working at Intel.

The first specification for the USB version 1.0 was introduced in 1996

Types of USB Connectors

Here are the most common types of USB connectors.

  • Type-A: The standard flat, rectangular interface that you find on one end of nearly every USB cable. Most computers have multiple USB-A ports for connecting peripherals. You’ll find them on game consoles, TVs, and other devices too. This cable only inserts in one way.
  • Type-B: An almost square connector, mostly used for printers and other powered devices that connect to a computer. They’re not very common these days, as most devices have moved onto a smaller connection.
  • Mini-USB: A smaller connector type that was standard for mobile devices before micro-USB. While not as common today, you’ll still see these on some cameras, the PlayStation 3 controller, MP3 players, and similar.
  • Micro-USB: The current standard (though slowly declining in popularity) for mobile and portable devices, which is even smaller than mini-USB. While you’ll still find micro-USB on all sorts of smartphones, tablets, USB battery packs, and game controllers, some have moved onto USB-C.
  • Type-C: The newest USB standard, this is a reversible cable that promises higher transfer rates and more power than previous USB types. It’s also capable of juggling multiple functions. You’ll see it on many new laptops and smartphones, including the MacBook, Pixel phones, and Nintendo Switch Pro Controller. We discuss USB-C more below.
  • Lightning: This isn’t a true USB standard, but is Apple’s proprietary connector for the iPhone, iPad, AirPods, and more. It’s a similar size to USB-C and comes standard on Apple devices released since September 2012. Older Apple devices use the much larger 30-pin proprietary connector.

In most cases, you’ll find USB cables have one standard type-A end and one type-B end of some sort. The type-A end powers the device, while the type-B end receives power. This is to prevent potential damage that would be caused by connecting two computers via USB-A,

for example.

The Mini and Micro connectors are considered smaller forms of type-B, even though “type-B” is usually not in their name.

In general, the cables you’ll use the most, and therefore need to replace, are micro-USB, USB-C, and Lightning.

USB Speed Standards

The three main iterations of USB’s speed are:

  • USB 1.x was the original standard and is ancient by modern benchmarks. You’re very unlikely to find devices using this standard nowadays.
  • USB 2.0 introduced many modern USB norms, including support for Mini and Micro cables, USB OTG (see below), and more. It’s the slowest speed of USB still used today. You’ll find it used on cheap flash drives, devices like mice and keyboards, and similar. Most computers also include a few USB 2.0 ports.
  • USB 3.x is the current standard for USB speeds. It’s much faster than USB 2.0 and thus recommended for devices like external hard drives. You can typically identify a USB 3.x port or connector by its blue coloring. Many USB 3.0 ports also have an SS symbol (which stands for SuperSpeed). Most new computers have at least one USB 3 port, and good-quality flash drives use this standard.

 You can use a USB 2.0 device in a USB 3 port, or a USB 3 device in a USB 2.0 port, but neither setup provides the extra speed benefit.

The below chart shows what connector types are compatible with which standards. Notice that micro-USB devices that support USB 3.x have a different plug. You’ll frequently see this on external hard drives.


USB-C is an emerging standard that has lots of promise. It’s smaller, reversible, and fast. USB-C can both receive and provide a lot more power than previous versions of USB. In fact, Apple’s MacBook line only has a single USB-C port, with the new MacBook Pros packing several-C ports.

Aside from data transfer, USB-C can also power devices, output display to a monitor, and more. Unlike USB-A, cables with USB-C connectors on both ends are standard and allow full utilization of its powers. However, USB-C to USB-A cables is also common, allowing for compatibility with older devices.

Your phone or tablet might use USB-C instead of micro-USB. Some laptops and tablets feature a USB-C port; the Nintendo Switch uses it for power too. Since USB-C hasn’t been adopted everywhere yet, you might need to buy some USB-C to USB-A adapters to ease the transition.

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