USB interface is the expansion port on the motherboard for connecting various external devices. These expansion interfaces, can be printers, external Modem, scanners, flash drives, MP3 players, DC, DV, mobile disk, mobile phones, tablet and other external devices connected to your computer. Moreover, by extending the interface also enables the interconnection between computers.
Currently, the common interface to a serial interface expansion (Serial Port), Parallel Interface (Parallel Port), universal serial bus interface (USB), IEEE 1394 interface.
Universal Serial Bus (Universal Serial Bus) referred to as USB, is the computer, digital, flat panel TVs and other products side glazing applications, an interface specification. USB interface is a four-pin interface, where the middle two pins to transfer data, both sides of the two-pin power supply to peripherals.
USB is the abbreviation for Universal Serial Bus. It is not a new bus standard, but used in the PC field of interface technology. USB is the end of 1994 by Intel, Compaq, IBM, Microsoft and other companies jointly proposed. But until recently, it was widely applied. From November 11, 1994 published a USB V0.7 version later, USB version has gone through years of development, has now been developed for the 2.0 version, a standard extension to the current computer interfaces. The current board is mainly used USB1.1 and USB2.0, the USB version of the compatibility between the well. USB plug with a 4-pin plug as standard, using the daisy-chain can connect all the peripherals up to 127 can be connected to external devices, and no loss of bandwidth. USB requires the host hardware, operating systems and peripherals to support three aspects of the work. The current board is generally used to support USB function control chipsets, motherboards are also equipped with USB interface socket, and in addition to the backplane connector, the board also set aside a USB pin, you can connect the chassis front As a USB interface for easy use (note that the wiring to the motherboard manual carefully read the map and press connect, do not pick the wrong leaving equipment damage). And the USB interface can also be connected via a special USB cable to achieve double machine interconnection, and more can be expanded through the Hub interface. With a transmission speed USB (USB1.1 is 12Mbps, USB2.0 is 480Mbps), easy to use, hot-swappable, connect flexible, independent power supply, etc., can connect a mouse, keyboard, printer, scanner, camera, flash drives, MP3 players, mobile phones, digital cameras, mobile hard drive, external optical floppy, USB, LAN, ADSL Modem, Cable Modem, etc., almost all external devices.
USB has two standards, namely, USB1.1 and USB2.0.
USB1.1 is the more common USB specification, the high-speed mode of transmission rate of 12Mbps, low speed mode of transmission rate of 1.5Mbps. Note: where b is the Bit mean, 1MB / s (megabytes / sec) = 8MBPS (megabits / second), 12Mbps = 1.5MB / s. Currently, the main home for the low-end scanner USB interface type.
COMPAQ, Hewlett Packard, Intel, Lucent, Microsoft, NEC and PHILIPS these seven companies jointly developed a standard USB 2.0 interface. USB2.0 specification is evolved by the USB1.1 specification. Its transfer rate reached 480Mbps, converted into MB for 60MB / s, sufficient to meet most of the peripheral speed requirements. It increases the maximum benefit for users is that means that users can use external devices to the more efficient, but also has multi-speed peripherals can be connected to a USB 2.0 line, unlike the USB 1.1 era, because of the high bandwidth makes more devices without worrying about data transmission bottleneck effect occurs. USB 2.0 can use the same specifications as the original definition of the USB cable, connector specifications are also identical, as in the premise of high-speed USB 1.1 to maintain the excellent characteristics, but also to ensure backward compatibility.
USB 2.0 in the "Enhanced Host Controller Interface" (EHCI) and USB 1.1 defines a compatible framework. It can be used for USB 2.0 Drive USB 1.1 device driver. In other words, all support USB 1.1 devices can be directly used on USB 2.0 interface without having to worry about compatibility issues, and like the USB cable, plug, etc. accessories can also be used directly.
But the mainstream scanner interface technology still remain in the USB1.1, its 12Mbps transfer rate can not meet people's needs. Thus, some users will turn their attention to transmission speed, higher performance, support for USB 2.0/IEEE1394 interface scanner. Although at present not many such products, but different brands of scanners look great difference.
USB (Universal Serial Bus) network, computer products, digital media and home resources to share, is a trend of 3C integration. TV with streaming media capabilities to achieve MP3, camera, cameras, mobile hard disk, U disk and the contents of various memory card directly on the TV broadcast, so that information sharing. Streaming TV and regular TV, the biggest difference is that the latter can only watch TV, fixed content, and streaming media clearer TV can not only watch TV programs, can also play digital cameras, mobile hard drives and other digital devices the pictures, music, movies, the original can only be played on a PC content in a larger, clearer view on the flat-panel TVs, so the whole family to enjoy together. The streaming media capabilities to achieve these wonderful intermediary must rely on as the "USB" interface.
Sales of flat-panel TV market there are still some products in order to reduce the cost of using low-speed USB1.1 interface as a streaming media interface, and this interface can not meet the massive flow of media equipment, power and transmission needs. Currently home digital devices such as MP3 has the capacity to G transition, digital cameras have already begun to millions of pixels of the new generation, high-capacity streaming media files must rely on reliable high-speed interface to smooth presentations, so buy streaming TV, we must first determine whether The use of USB2.0 high speed interface replaced.
USB interface is located on the front panel USB extension interface. Currently, the use of a variety of external devices USB interface more and more, such as mobile hard drives, flash drives, digital cameras, etc., but in the use of these devices (especially the frequent use of mobile storage devices) every time they drill into the chassis back to use the onboard USB interface board is obviously inconvenient. Front USB ports give users in this area provide a good ease of use. Currently, the front chassis USB interface has almost become the standard configuration, there is no front USB port chassis has been very rare.
USB interface attached to the chassis to use the USB cable connected to the motherboard on the corresponding front USB pin (typically 8-pin, 9-pin or 10-pin, two USB pairs, each of which use 4-pin USB transmission signal and power) can be used on. When connecting the USB interface must first read the motherboard manual and chassis manual and its related content, it can not be connected the wrong way, or will cause damage to the USB device or motherboard.
In addition, when using the front USB port powered USB interface should pay attention to the problem of insufficient power in the use of larger USB devices, to use an external power supply or motherboard rear of the chassis directly using the USB interface board to avoid USB device is not used or damaged.