USB, an abbreviation of Universal Serial BUS (Universal Serial BUS), which is abbreviated as "pass-through", is an external BUS standard, which is used to standardize the connection and communication between computers and external devices. It is the interface technology that applies to PC domain. USB interface supports plug and play and hot plug function. USB was jointly proposed by Intel, compaq, IBM, Microsoft and other companies in late 1994.
Until recently, however, it was widely used. The USB version has been developing for many years and has now been developed as a 3.0 version, becoming the standard extension interface in computers. At present, the main board is mainly USB1.1 and USB2.0, which can be well compatible with each USB version. USB with a 4 pin (see standard of 8 needle) as a standard plug, plug the Daisy chain form can connect all of the peripherals, up to 127 external devices can be connected, and not loss of bandwidth. USB requires the support of the host hardware, operating system and peripherals to work. The motherboard is generally using the chipset of supports USB function, also install a USB socket on the main board, and, except for the back of the socket on the motherboard have a USB pin reserved, can through the attachment received in front of the chassis as the front USB interface for use. The USB interface can also be connected to the two machines via a dedicated USB cable, and more interfaces can be extended through the Hub. USB has the transmission speed (USB1.1 is 12 MBPS, USB2.0 is 480 megabits per second, start is 5 Gbps), easy to use, support hot plug, flexible connection, independent power supply etc, and can connect the mouse, keyboard, printer, scanner, camera, USB flash disk, MP3 players, mobile phones, digital cameras, mobile hard disk, floppy disk, USB external light card, ADSL Modem, Cable Modem, etc., almost all the external devices.
The USB interface can be used to connect up to 127 peripherals such as mouse, modem and keyboard. Since its launch in 1996, USB has successfully replaced serial ports and parallel ports, and has become one of the must-have interfaces for personal computers and a host of smart devices today.