Chassis Plans CCIR-17, Техническое описание

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Chassis Plans CCIR-17 Technical Reference Appendix D – DVI-D versus DVI-I
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Appendix D – DVI-D versus DVI-I Connectors
The Digital Visual Interface (DVI) is a video interface standard designed to provide very high visual quality on
digital display devices such as flat panel LCD computer displays and digital projectors. It was developed by an
industry consortium, the Digital Display Working Group (DDWG). It is designed for carrying uncompressed
digital video data to a display. It is partially compatible with the High-Definition Multimedia Interface (HDMI)
standard in digital mode (DVI-D), and VGA in analog mode (DVI-A).
The LCD controllers offered with the CCI keyboards offer DVI-D and DVI-I, depending on which controller is
selected. This discussion is presented to help clarify the difference between the various flavors of DVI.
Overview
The DVI interface uses a digital protocol in which the desired illumination of pixels is transmitted as binary data.
When the display is driven at its native resolution, it will read each number and apply that brightness to the
appropriate pixel. In this way, each pixel in the output buffer of the source device corresponds directly to one
pixel in the display device, whereas with an analog signal the appearance of each pixel may be affected by its
adjacent pixels as well as by electrical noise and other forms of analog distortion.
Connectors
The DVI connector usually contains pins to pass the DVI-native digital video
signals. In the case of dual-link systems, additional pins are provided for the
second set of data signals.
As well as digital signals, the DVI connector includes pins providing the same
analog signals found on a VGA connector, allowing a VGA monitor to be
connected with a simple plug adapter. This feature was included in order to
make DVI universal, as it allows either type of monitor (analog or digital) to be
operated from the same connector.
The DVI connector on a device is therefore given one of four names,
depending on which signals it implements:
DVI-D (digital only)
DVI-I (integrated, digital & analog)
The connector also includes provision for a second data link for high
resolution displays, though many devices do not implement this. In those that
do, the connector is sometimes referred to as DVI-DL (dual link).
The long flat pin on a DVI-I connector is wider than the same pin on a DVI-D
connector, so it is not possible to connect a male DVI-I to a female DVI-D by
removing the 4 analog pins. It is possible, however, to connect a male DVI-D cable to a female DVI-I connector.
Many flat panel LCD monitors have only the DVI-D connection so that a DVI-D male to DVI-D male cable will
suffice when connecting the monitor to a computer's DVI-I female connector.
Essentially, DVI-D is the same as DVI-I with DVI-D missing the analog portion of the signals. A DVI-D connector
and monitor can connect to a DVI-I output and function. A DVI-I monitor can connect to a DVI-D output with the
caveat that no analog video will be available.