Universal serial bus (USB) technologies allow the rapid transfer of data from one computing device to another. The USB standard was designed through a cooperative effort by seven of the largest companies in the computing and electronics industry to standardize data transfer formats and allow for more uniformity in the connections and interfaces used to link devices to computers and to each other. USB connections were designed to replace some of the serial and parallel connections previously used in computing hardware and continue to evolve to meet the needs of manufacturers and consumers in the expanding electronics marketplace. USB devices typically feature plug-and-play functionality; this means that they can be connected and disconnected from the computing device without requiring a shutdown of the system. In some cases, USB computer connections can also serve to charge devices using the on-board power source of the computer system.
USB version 1
The initial release of the USB standard in November of 1995 had significant flaws and was not immediately adopted by consumers and electronics manufacturers. It called for data rates of 1.5 megabits per second for low bandwidth applications and 12 megabits per second for full bandwidth usage. It was not until the release of USB version 1.1 almost three years later that USB technologies became widely accepted, available and popular in the U.S. The first USB devices were mostly limited to portable disk drives and user input devices like keyboards and joysticks, but as the USB format became more popular a wider range of devices began implementing this industry standard.
USB version 2
The second iteration of the USB standard was introduced in April 2000 and represented a major advance in speed and sophistication. A new, higher level of bandwidth was supported that was exponentially faster than before at 480 megabits per second. Referred to as hi-speed USB, this upgrade allowed data transfers of up to 60 megabytes per second and paved the way for higher speed file transfers; it also introduced a number of new connector formats including Mini-A, Mini-B and Micro-USB cables and connectors. Because USB 2.0 provided higher speed and increased bandwidth functionality, it became practical to use USB connections for printers, DVD burners and players, MP3 players and other digital storage devices, expanding the market for these versatile connections.
USB version 3
Released in November of 2008, USB 3.0 is the fastest and most advanced standard for data transfer and can manage speeds of up to 625 megabytes. The standard is designed to be both backwards compatible with USB 2.0 and to allow upgrades for newer advances in USB technology. Along with the increase in speed, USB 3.0 consumes less power than previous versions, making it a green-friendly computing solution. USB 3.0 devices include high-definition video systems including webcams, video recorders, cameras and Blu-Ray players and drives. These high-end electronic devices perform better with USB 3.0 than the previous version and take advantage of the higher bandwidth and lightning-fast speed of the USB 3.0 interface.
A variety of physical connectors are used in order to allow devices to interface using the USB protocols. These connections are defined as male or female; generally the male interfaces are used on the connecting wires while the female connectors are integrated into the electronic devices, but this is not always the case. Interface types include:
- Standard-A – Along with the Standard-B connector, this connector type was introduced with the release of USB 1.1 and continues to be the most common type of USB plug on the market. It is designed to fit into a computer or hub port and to transfer data and electricity simultaneously, allowing devices to charge while in use.
- Standard-B – Commonly used for printer or digital camera connections, this connecting plug also provides power and data transfer simultaneously, but usually fits into a device port rather than a computer port.
- Mini-A and Mini-B – The advent of cellular phones and devices and their increasing popularity led to the introduction of the Mini-A and Mini-B USB connectors to fit these smaller devices.
- Four-prong Mini – Designed specifically for mini-USB digital cameras and other devices, these specialized USB connectors have mostly been abandoned in favor of the newer Micro-USB interfaces.
- Micro-USB – Available in A, B, and AB varieties, Micro-USB connections are fast becoming the industry standard and are compatible with a wide range of newer digital and personal computing and communications devices.
The future of USB
While USB 4.0 has yet to be announced, experts have speculated that the next generation of USB connections may use fiber-optic technologies to provide even more speed and greater transfer capabilities for business and personal use. Regardless, the USB standard has served the electronics industry well and is likely to remain in place for years to come.