Universal Bus connection is a standard used to define communication protocols between the bus cables and connectors in computers and electronic devices. It was designed to standardize the communication and power supply of computer peripherals including keyboards, mouse, portable devices and disk drives to personal computers.
The first USB design was USB 1.0 which gave a data transfer rate of 1.5 Mbit/s for the Low speed and 12 Mbits/s for the full speed. The second generation called the USB 2.0 had a 480 Mb/s data rate transfer specification.
USB3.0 delivers data rates of up to 5Gbit/s with decreased power consumption, more power output and backward compatibility with previous versions. It incorporates a parallel high speed bus known as the SuperSpeed. USB 3.0 uses full duplex communication as well as payload throughput of up to 4 Gbits/s. USB 3.0 has a low-power optimum power variant transmitting capabilities that allow it to give 150mA and 900Mm A respectively; in the same breath, it transmits data at super high speeds. In addition, it has a battery charging specification that can handle 1.5 A for ports that can handle 5 A current source without concurrent data transmission.
USB uses an asymmetrical topology comprising of host, multitude of downstream USB ports and numerous peripheral devices interlinked in a n-tier star topology. The number of ties can be increased to a maximum of five. USB host can execute many host controllers with each host controller capable of giving more than one USB ports. A maximum of 127 devices can be linked to a single host controller while hubs are used to link devices.
Reference
Atiquzzaman, M. (2012). USB Technology. Journal of Networkingand Computer Applications .
James-Yves Roger, J.-Y. R.-S. (2008). Technologies for the information society:developments and opportunities. ABA journal .
Mueller, S. (2002). USB. Upgrading and repairing PCs Journal .
