What is USB ?
USB short for Universal Serial Bus, is an industry standard that defines cables, connectors for connection, communication, and power supply between computers and devices.
USB versions and data transfer speeds :
USB short for Universal Serial Bus, is an industry standard that defines cables, connectors for connection, communication, and power supply between computers and devices.
- USB was designed to standardize the connection of computer peripherals (including keyboards, pointing devices, digital cameras, printers, portable media players, disk drives and network adapters) to personal computers, both to communicate and to supply electric power.
- Before USB was invented, computers used to connect to peripherals like keyboards, mice, printers, scanners, cameras and so on, by using various types of ports and connections.
- For instance, before USB was adopted, keyboards and mice usually connected via PS/2 connectors or by using serial ports. Printers and scanners usually connected via parallel ports.
- We also needed a game port if we wanted to play games on our computer using a joystick or a game pad.
USB versions and data transfer speeds :
USB 1.0 and USB 1.1 : These are the first iterations of the USB interface, released in 1996 and 1998 respectively, and they were capable of data transfers of up to 1.5 Mbps, respectively 12 Mbps. At the time when they were developed, USB 1.0 was also known as Low Speed USB, while the USB 1.1 was known as Fast Speed USB.
USB 2.0 : It is also known as Hi-Speed USB, was released in April 2000 and it supports maximum theoretical data transfer speeds of up to 480 Mbps. In reality, the maximum effective throughput is limited to 280 Mbps or 35 MB/s. USB 2.0 is backward compatible with USB 1.0 and USB 1.1, meaning that you can use old devices with USB 1.x ports to connect to newer devices that have USB 2.0 ports.
USB 3.0 : It was released in November 2008 and it is also known as Super Speed USB. It can support theoretical data transfer speeds of up to 5 Gbps, but the real-life speeds we can get on it are around 3.2 Gbps or 400 MB/s.
USB 3.1 : It was released in July 2013 and is also known as Super Speed+ USB. It is capable of theoretical data transfers of 10 Gbps, double that of USB 3.0. In reality, the maximum achievable transfer speed is of 7.2 Gbps or 900 MB/s.
USB Types :
- USB Type A
USB Type-A is the original design for the USB standard with a flat and rectangular shape.Type-A ports are mostly in host devices, including desktop computers, laptops, game consoles, media players and so on.
- USB Type B
The Type-B connector is the other end of a standard USB cable that plugs into peripheral device (such as a printer, a phone, or an external hard drive). The Type-B connector and its respective port come in many different designs to accomodate to the size of the peripheral device. Up to now there are five popular designs for the USB Type-B's plugs and connectors
- USB Type C
Physically, the Type-C port and connector is about the same size as that of the Micro-B USB mentioned above. A Type-C port measures just 8.4mm by 2.6mm. This means it's small enough to work for even the smallest peripheral devices. With Type-C, both ends of the USB cable are the same, allowing for reversible plug orientation.
Type-C USB supports USB 3.1 with the top speed of 10Gbps and has much higher power output of up to 20V(100W) and 5A.
Example :