universal power supplies

Universal Serial Bus (USB) is a serial bus standard to interface devices. It was designed for computers such as PCs and the Apple Macintosh, but its popularity has prompted it to also become commonplace on video game consoles, PDAs, cellphones; and even devices such as televisions and home stereo equipment (e. g. Find, compare and buy products from thousands of trusted retailers. , mp3 players), and portable memory devices.

The radio spectrum-based USB implementation is known as Wireless USB.

Overview

A USB system has an asymmetric design, consisting of a host controller and multiple daisy-chained devices. Additional USB hubs may be included in the chain, allowing branching into a tree structure, subject to a limit of 5 levels of branching per controller. No more than 127 devices, including the bus devices, may be connected to a single host controller. Compliance Testing - REO-USACOM. Modern computers often have several host controllers, allowing a very large number of USB devices to be connected. USB cables do not need to be terminated.

Because of the capability of daisy-chaining USB devices, early USB announcements predicted that each USB device would include a USB port to allow for long chains of devices. In this model, computers would not need many USB ports, and computers shipped at this time typically had only two.