Transmission technology into the digital era, users and manufacturers are increasingly focusing on the quality requirements of the digital display, digital display interface standard combination of hardware graphics card, and therefore more subject to the attention of the progress of its development.USB2.0 yet mature, dominant video transmission interface IEEE1394a speed, but 400Mbps, can only transmit compressed digital video; Even USB2.0 transfer speed (480Mbps), unable to meet the ever-changing digital audio and video transmission needs.More important, in addition to controlling the message requires two-way outside most of digital video as long as the one-way transmission, however IEEE1394a is completely two-way design, so that is not easy to expand the transmission bandwidth, digital video output derivative application is therefore restricted. In view of this, the Video Electronics Standards Association VESA (Video Electronics Standards Organization) in June 1997 proposed P & D 1.0 (Plug & Display) of digital video specifications, but also in order to market the number of bits to interface have uniform standards, this openthe first digit display interface standard stage. P & G features combined the IEEE1394a with USB1.0 data transfer interface functions, the digital display features more diversified.Although the P & G capable of simultaneous transmission of analog and digital message, but is also due to P & D not only plays output digital video's role at the same time take on a USB or IEEE1394 as compatibility of both the external lines of the function, so that the price of P & D high, lead can not be in the marketsprung up everywhere. However, P & D of message transmission way TMDS (Transition Minimized Differential Signaling; frequency to 165MHz) Specifications are quite outstanding, the main function is to allow uncompressed digital video directly transmitted on the display, and can allow video message without any distortion, therefore continued to be in use in the future DFP, DVI and even HDMI stage. After DFPG (Digital Flat Panel Group) in February 1999, another DFP digital display interface standard, DFPG led by Compaq Digital Interface Specification Alliance, which ATI is the production of well-known manufacturers of DFP interface card withDFP interface specification standard graphics card ATI2 the Range Pro the LV Voodo the 3500 Number Nine SR9. In fact very similar, DFP and P & D specifications improved P & D, electrical specifications are almost the same.Except DFP is a purely digital rather than with analog message passing, as well as not to act as USB and IEEE1394a and other interface functions, the difference is that the price of DFP's relatively inexpensive market price than the P & D comes close to many, even VESA also used to use the DFP standard. DFP fatal, however, is that the message resolution is limited to SXGA (1280 × 1024); and only one RGB channel, can not ensure that the transmission quality; There can only be connected with the limitations of digital flat-panel displays, and thus it exists only on the market a short active, it would not be surprising. April 1999 DDWG (Digital Display Working Group) DVI 1.0 (Digital Visual Interface) specifications, where the DDWG is in September 1998 by Intel, Compaq, Fujitsu, HP, IBM, NEC and Silicon Image and other manufacturers arethe leading organizations in the Silicon Image follow the previous P & G message transmission TMDS-based, developed DVI PanelLink technology, can achieve high-performance digital display quality. The technology to filter out electronic noise impact of the transmission line and twisted pair transmission message will not be due to external electrical interference and sensitive.Display DVI connector and PC display DVI interface card connected directly between the transmission of digital messages, video images do not need to go through any conversion, so you can save time, accelerate the transmission speed, eliminate smearing phenomenon;digital message transmission does not weaken, showing the color will be more pure and realistic. Furthermore DVI has two groups of connection (link) makes its PanelLink technology can support VGA, UXGA (60 Hz single-link processing pixel format capability, resolution up to 1600 x 1200), HDTV (1920 x 1080),QXGA (dual-link processing the pixel formats capacity 60 Hz, resolution up to 2048 × 1536) digital video format; and clock speed in the 25-165MHz single-link transmission bandwidth up to 1.65 Gbps to dual-link bandwidth can exceed 2 Gbps. DVI abandon the P & D burden to take on many roles, also avoid DFP new incompatible overkill. DVI can transmit analog message can be equipped with the then traditional CRT; serves two RGB channel, completely pass digital messages, to ensure the quality of the digital transmission; PnP compliant with the advantages and DVI, and therefore able to efficiently meet the high-resolution with the demand for high-bandwidth transmission, DVI recent years has become the most widely used LCD Monitor Laptop digital Interface.With the mature plasma TV as well as the concept of the digital home, beginning in 2004, DVI digital display interface standard applications from your PC toward the kinds of consumer electronics products (such as DVD recorder, Set-top Box, D-VHS player, AV receiver ...... and so on). HDMI (High Definition Multimedia Interface; HDMI) recently hot by Hitachi, Panasonic, Philips, Sony, Thomson, Toshiba, Silicon Image vendors such as co-founder of a new generation of digital display interface standard, the motivation is to the DVI only send video messages, anddoes not contain the digital audio, the DVI research and development beginning is for the PC Monitor, therefore HDMI is specifically enhance support video audio transmission quality consumer electronics products.HDMI or root DVI-based development from a compatible DVI / HDCP interface, can transmit uncompressed high quality video, and also added the functionality to support multi-channel audio signals, bandwidth speeds of up to 5 Gbps. HDMI can support SXGA, UXGA, SDTV, HDTV and other digital video formats, as well as the CD, DVD-Audio, Dolby Digital / the DTS and other digital audio formats suitable for digital TV, DVD recorder, PVR, video conversion (Set-top Box ) and other audio-visual products.