The Complete History of USB: One Port Revolution

When you think about powerful inventions or innovations in the history of computers, what comes to mind? Windows, Mac, iPod. There is one interface that most people do not think of – the Universal Serial Bus (USB). Do you even know the history of USB? We are about to find out. 

Universal Serial Bus is an input/output bus that is used to transfer data at greater speeds than older parallel and serial interfaces. This interface has several benefits over previous bus systems. It is a widely supported standard, which simplifies buying external devices.

It is the most successful PC interface. PCs, smartphones, tablets, and other devices have USB ports that can connect to everything from audio and video devices, drives, printers, cameras and keyboards among others.

A USB cabling system creates its own independent bus, and USB devices are hot swappable. A Universal Serial Bus device can be disconnected and another one swapped into the system without restarting your personal computer.

Advantages of USB

  • Ease of Use

The major design goal for the Universal Serial Bus was ease of use. It features one interface for many devices, which is versatile enough for any standard peripheral function and devices with specialized functions.

A typical PC would have more than one port for supporting multiple devices. In fact, you can even use a USB hub to add more ports. Universal Serial Bus is hot swappable. You can connect as well as disconnect a device whenever you want without restarting your computer.

The interface has automatic configuration. When you connect a USB device to your PC, the OS will detect the device and load the suitable software driver. Basically, you do not have to reboot the system in order to use a device for the first time.

There is no power supply required. The USB interface is integrated with power supply and ground lines that provide a nominal voltage from the PC or hub. A connected device draws its power from the bus instead of using a dedicated supply.

  • Multiple Speeds

Universal Serial Bus supports five speeds: SuperSpeedPlus (10 Gbps), SuperSpeed (5 Gbps), high speed (480 Mbps), full speed (12 Mbps), and low speed (1.5 Mbps). In PCs, USB 3.1 host controllers support all the five speeds. USB 3.0 host controllers support all but SuperSpeedPlus. On the other hand, USB 2.0 supports high, full, and low speeds.

The bus speed defines the rate that information travels on the bus. Other than application data, the bus has to carry status, control and error-checking info, and multiple devices can share a bus.

  • Reliable & Power Saving

The hardware and protocols used make Universal Serial Bus interface highly reliable. The hardware qualifications for USB drivers, receivers as well as cables guarantee an electrically quiet standard that removes noise that could lead to data errors.

The Universal Serial Bus protocols enable detecting errors in received data as well asinforming the sender so it can retransmit. The hardware conducts the detecting, informing and retransmitting without software or user support.

Protocols and power saving circuits reduce the power consumption of a USB device, and at the same time keeping the device ready to communicate when needed. Reduced power consumption will definitely save you money.

Evolution of USB

The invention of USB replaced and/or consolidated many earlier types of interface. Parallel ports, serial ports and many separate power supplies. The creation of Universal Serial Bus interface began in 1994, supported by seven companies.

The companies include: Compaq, IBM, DEC, Microsoft, Nortel, NEC, and Intel. The idea behind it was to allow the removal of serial and parallel ports, and use a simple universal connector. Today, the developers and maintainers of the USB standard form the USB Implementers Forum.

  • USB 1.0

USB 1.0

USB 1.0 was the first release at the beginning of 1996. It provided specified data rates of 1.5 megabits per second at low bandwidth and 12 megabits per second at full bandwidth. This interface doesn’t allow for pass-through monitors or extension cables.

  • USB 1.1

USB 1.1 followed in 1998 and it corrected problems that had become apparent in 1.0, especially in hubs. In addition to fixing issues, this interface became widely accepted and implemented by computer manufacturers.

This version had a maximum data rate of up to 12 megabits per second. This may not be enough as far as current standards are concerned. However, at the time of its release, USB 1.1 allowed computer and device companies to replace a large number of connector and port types.

  • USB 2.0

This standard arrived in 2001, and it features a higher data rate of 480 megabits per second (theoretical), which is forty times faster compared to 1.1 standard. The Universal Serial bus 2.0 was launched as a specification.

The 2.0 standard is backward compatible with the previous one. Therefore, if you have the ideal connectors, it will be easy for you to plug a 1.1 device into a 2.0 port on your PC and the device will function properly. However, the data rate will be limited to 1.1 maximum speed.

  • USB 3.0

USB 3.0

In 2008, the Universal Serial Bus interface got another huge speed increase of up to 5 gigabits per second. This version had a lower power consumption along with increased power output. It was also backward compatible with USB 2.0. The first computers and devices with 3.0 ports (SuperSpeed) came out in 2010.

  • USB 3.1

This version was released on July 2013 by the USB group. This specifications replaced the SuperSpeed 3.0 with 10 gigabits per second. This minimized line coding overhead to about 3 percent. In this case the encoding scheme was changed to 128b/132b.

The 3.1 standard is compatible with 2.0 and 3.0 versions. The main advantage of USB 3.1 is the enormous speed increase of 10 gigabits per second. Apart from the speed, there are no major changes when compared to 3.0 as far as connection types are concerned.

USB Connections

There are several USB types, including some that have been added while the specification progressed. The original USB specification detailed Type-A and Type-B plugs and receptacles.

Type A

These USB connections were initially referred to as Standard-A connectors. They’re rectangular and flat in shape. The data connectors are recessed in the plug as compared to the outside power connectors.

This allows power to connect first, preventing data errors by allowing the device to power up first and then transfer data. Type-A connections are the most popular and widely used connectors. They’re mainly supported by USB 1.1, 2.0, and 3.0.

Type A connectors are popular with most computer-like devices, including all kinds of computers, such as tablets, netbooks, laptops, and desktops. These connections are also found on smart TVs, streaming players, and video game consoles.

Micro USB

This is a miniaturized version of the USB interface is engineered for connecting mobile and compact devices, including digital cameras, photo printers, GPS devices, MP3 players, and smartphones.

Micro USB connectors are available in three forms: micro USB 3, micro B, and micro A. Micro B and USB 3 are much alike, but USB 3 has an extra pin group. All micro USB versions are hot-swappable and plug and play. 

Type B

Officially known as Standard-B connectors, Type B connections have a squared shape with a large square overhang or a slight rounding on the top. However, the shape depends entirely on the version of the Universal Serial Bus.

Type B connections are supported in every version of Universal Serial Bus interface, including USB 1.1, USB 2.0, and USB 3.0. There is another Type B connection referred to as Powered-B that is only supported by USB 3.0.

Type B connections are most popular with larger devices, such as scanners and printers. These connectors are also found on external storage devices, such as hard drive enclosures, floppy drives, and optical drives.

Mini USB

This version of USB interface is mostly found on digital cameras. The endpoints of mini USB are smaller compared to the endpoints of regular USB cables. While both micro and mini USB function the same way, majority of electronic devices use micro USB technology.

Type C

The A and B type connectors are now old history. The new connector is called USB type C. So, what does USB-C gives us that type A and B connectors cannot. First of all the USB C is small; therefore, there is no need of mini USB or micro USB connectors.

The type C connector can be used on everything from an Android smartphone all the way up to a server. Secondly, USB type C is rated at 100 W, which means the USB cable can be used to charge more than just a tablet or a smartphone.

Thirdly, the USB-C cable is reversible. Therefore, it does not matter which way around you connect the cable. No more trying to plug in a cable and find out that it was supposed to be the other way around.

Finally, the USB-C cables have a USB type C plug at both ends. There are no longer be a type-A socket plug and a type-B socket plug. They’re truly interchangeable.

USB in the Future

The future of Universal Serial Bus interface is USB-C. It is becoming a new standard connector for transmitting both data and power. Micro USB which is more frequently used on Android and other devices is now aging.

Comparing USB-C to micro USB, USB C is oval shaped while micro USB is more of a trapezoid shaped. The oval shape of USB-C allows you to flip it horizontally and it will still go into the charging port.

The USB 3.1 version on USB-C can offer 10 gigabytes per second. There is also the new Thunderbolt 3 (Intel’s invention), which now offers 40 gigabytes per second. There is no doubt that USB-C is the future of USB, but there’s also the new Thunderbolt 3.


The history of USB has come a long way, and there is no doubt that the future of USB is going to be better than the present.Essentially, it was designed to be plug and play. Just plug in the peripheral and it should work, provided the software is installed to support it. 

As we have seen the USB cable varies mostly based on the USB peripheral connector on the external device end. The USB standard specifies three broad types of connectors (type-A, type-B, and type-C). Type-C being the most recent and the future of USB.

The aim of USB type C is to make charging and data transfer more efficient. In fact, it is reversible; so you can plug any end into your smartphone. The transfer speeds are enormous as seen with the USB 3.1 on USB-C.

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