USB is short for Universal Serial Bus. A USB is a plug-and-play interface that enables a computer to interact or communicate with other devices (Peripheral devices). There exists a wide range of USB-connected devices such as mice, keyboards, flash drives, and even music players. A USB may also be used to transfer power to other electronic devices, like tablets and smartphones. In January 1996, the first version of USB technology was invented and released to the market. It was named USB 1.0 and was quickly accepted by big industry players like Microsoft, Intel, and Compaq. Later on, over the years, the technology has improved systematically to USB 1.1, USB 2.0, USB 3.0, and currently USB 3.1. The fundamental difference between these new releases is the increase in transfer speeds.
After introducing USB 1.0 in 1996, the technology underwent many iterations intending to improve the technology. The main motive here was to increase transfer speeds to accommodate the new industry demands. Below are the transfer speed limits for the different iterations.
The USB 1.0 Low Speed had a maximum transfer rate of 1.5 Megabits per second (Mbps). It was quickly followed by USB 1.1 Full Speed, which had a limit of up to 12 Mbps, which translates to 1.5 Megabytes per second(MBps). USB 2.0 High Speed was later rolled out with a stunning 480 Mbps of transfer speed, which converts to about 60 MBps. Finally, USB 3.0 SuperSpeed has a data transfer rate of 5 Gigabits per second(Gbps), about 625 MBps.
There is a USB port and a USB cable that is plugged into the USB port. When we refer to the USB as a plug-and-play interface, we mean that a USB component/device does not require to be plugged into or unplugged from the computer before it is powered on. This feature is referred to as "hot-swappable" in that; any USB device can be connected or disconnected from the computer while the machine is running. In addition, the computer will register the connected USB device as another storage area and show all the files contained within it. This is a revolutionary feature since most of the other computer ports required the user to shut down the computer before connecting the peripheral devices.
The introduction of USB technology was also considered one of the best things that ever happened to the current personal computers. Several other plugs had been developed over the years to handle different types of data transfer, and each plug was specific to a peripheral device. For example, some of these plugs were meant to handle modems, some of the connections handled printers, while others were meant for keyboards and mice. The introduction of USB combined all these ports into one universal port that can handle printers, smartphones, and external drives. This compatibility was a key feature that made USB technology very appealing.
USB 2.0 is an interface (external interface) used on a computer and other digital devices for data transfer via a cable. The terminology "2.0" is used strategically to refer to the version or standard of the external interface. The USB 2.0 was released to the market in 2000. Although USB 3.0 was made the industry standard in 2008, it is designed to be backward compatible. Backward compatibility means that the technology is cross-compatible with older versions of the technology, such as USB 2.0. This makes the fundamental difference between USB 2.0 and 3.0 to be the data transfer rates.
Again, for a USB 2.0, there is a standard maximum approved length of cable. A USB 2.0 cable is about 5 meters (approximately 16 feet). This length is mathematically determined to ensure that signals travel efficiently through the cord. The 16 feet limitation is arrived at based on how fast a signal travels via the cable. If the signals take a bit too long, the connected devices will show that the connection is lost. As the case of USB 2.0 technology, any cable longer than 16 feet will exceed the time, and hence communication will be lost.
USB technology was an invention that revolutionized various sectors of the computer. As a result, a majority of industry players and native computer components unanimously adopted the USB technology. The common native components are keyboards, external hard drives, mice, networking hardware, and printers. Some other external devices that use the USB data ports are digital cameras, cable boxes, mobile phones, and other media players.
After several years of working with USB 2.0, the data transfer speeds that it offered started to limit the computing trends. So, in November 2008, USB 3.0 became the official new standard adopted by the industry. USB 3.0 was introduced with more pins incorporated in the new connections. The introduction of more pins enabled increased speeds earning the name "Super Speed." The technology allows for data transfer speeds of up to 5 Gbps. It is also designed to be backward compatible to accommodate older versions of USB 2.0 like "full-speed" and "hi-speed" rates.
USB 3.0 has different types of connectors. The “male” connector is referred to as the plug on a flash drive or USB 3.0 cable. The other "female" connector on the USB 3.0 extension cable, device, or computer port is the receptacle. The following are the different common connectors of USB 3.0
The USB 3.0 manages to realize a significant increase in speeds due to four more wires in the data cable totaling six wires. The technology, therefore, supports full-duplex communication. This type of communication means that it has the ability to send and receive data simultaneously. It is also power efficient.
As of the time of writing, the current standard USB in use is the USB 3.1, but it hasn't yet bet adopted by many devices. The latest MacBook Pro models use this new USB 3.1. There are confirmed plans to roll out USB 3.2 soon since its technical aspects have been tried and tested. Shockingly, while all these are happening, the USB Promoter Group has moved a step further to announce plans for USB4. Note that the naming system has changed, eliminating the space character between “USB” and the version number. In the same light, the group has decided to now rename USB 3.0 as USB 3.2 Gen 1, USB 3.1 USB, as USB 3.2 Gen 2. Here is more on USB4 from Gizmodo.
Despite USB 3.0 being backward compatible with previous USB technologies, to achieve the desired USB 3.0 speeds, one needs to use a compatible 3.0 device and cable. On the other hand, the USB interface is praised for changing the trend from several incompatible ports and plugs into a universal system. The universal system offers a single mode of connection for almost all peripheral devices.