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'''Digital Visual Interface''' ('''DVI''') is a [[video display interface]] developed by the [[Digital Display Working Group]] (DDWG).
DVI devices manufactured as DVI-I have support for analog connections, and are compatible with the analog [[VGA]] interface<ref name="2000 Press Release">{{cite news|url=http://www.ddwg.org/articles.asp?id=22|title=Digital Visual Interface adoption accelerates as industry prepares for next wave of DVI-compliant products|date=February 16, 2000|publisher=DDWG, copy preserved by [[Internet Archive]]|access-date=29 March 2012|url-status=bot: unknown|archive-url=https://web.archive.org/web/20070828233809/http://www.ddwg.org/articles.asp?id=22|archive-date=28 August 2007}}</ref> by including VGA pins, while DVI-D devices are digital-only. This compatibility, along with other advantages, led to its widespread acceptance over competing digital display standards [[Plug and Display]] (P&D) and [[VESA Digital Flat Panel|Digital Flat Panel]] (DFP).<ref name="Competing standards">{{cite web|url=http://www.tomshardware.com/reviews/tft-guide-part-3,117.html|title=TFT Guide Part 3 - Digital Interfaces|last=Eiden|first=Hermann|date=July 7, 1999|publisher=TomsHardware.com|access-date=29 March 2012}}</ref>
==History==
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===TMDS===
Digital video [[pixel]] data is transported using multiple TMDS [[twisted pair]]s.
====Single link====
A ''single link'' DVI connection has four TMDS pairs. Three data pairs carry their designated 8-bit RGB component (red, green, or blue) of the video signal for a total of 24 bits per [[pixel]]. The fourth pair carries the TMDS clock. The binary data is encoded using [[8b/10b encoding]]. DVI does not use [[packet (information technology)|packetization]], but rather transmits the pixel data as if it were a [[rasterized]] analog video signal. As such, the complete frame is ''drawn'' during each vertical refresh period.
====Dual link====
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===DDC===
Like modern analog [[VGA connector]]s, the DVI connector includes pins for the [[display data channel]] (DDC), which allows the graphics adapter to read the monitor's [[extended display identification data]] (EDID). When a source and display using the DDC2 revision are connected, the source first queries the display's capabilities by reading the monitor EDID block over an [[Inter-Integrated Circuit|I²C]] link.
===Cable length===
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In addition to digital, some DVI connectors also have pins that pass an analog signal, which can be used to connect an analog monitor. The analog pins are the four that surround the flat blade on a DVI-I or DVI-A connector. A [[Video Graphics Array|VGA]] monitor, for example, can be connected to a video source with DVI-I through the use of a passive adapter. Since the analog pins are directly compatible with VGA signaling, passive adapters are simple and cheap to produce, providing a cost-effective solution to support VGA on DVI. The long flat pin on a DVI-I connector is wider than the same pin on a DVI-D connector, so even if the four analog pins were manually removed, it still wouldn't be possible to connect a male DVI-I to a female DVI-D. It is possible, however, to join a male DVI-D connector with a female DVI-I connector.<ref name="A+ Study Guide book">{{cite book|last1=Docter|first1=Quentin|last2=Dulaney|first2=Emmett|last3=Skandier|first3=Toby|title=CompTIA A+ Complete Deluxe Study Guide: Exams 220-801 and 220-802|year=2012|publisher=John Wiley & Sons, Inc.|___location=Indianapolis, Indiana|isbn=978-1118324066}}</ref>
DVI is the only widespread video standard that includes analog and digital transmission in the same connector.<ref>{{cite book |last=Kruegle |first=Herman |title=CCTV Surveillance: Analog and Digital Video Practices And Technology |publisher=Butterworth-Heinemann |isbn=0-7506-7768-6 |page=268 |chapter=8 |chapter-url=https://books.google.com/books?id=DaQY8CrmqFcC&q=DVI+is+the+only+widespread+video+standard+that+includes+analog+and+digital+transmission+options+in+the+same+connector.&pg=PA268 |year=2006 }}</ref>
Some [[DVD player]]s, [[High-definition television|HDTV]] sets, and [[video projector]]s have DVI connectors that transmit an encrypted signal for copy protection using the [[High-bandwidth Digital Content Protection]] (HDCP) protocol. Computers can be connected to HDTV sets over DVI, but the graphics card must support HDCP to play content protected by [[digital rights management]] (DRM).
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** [[WQUXGA]] ({{resx|3840|2400}}) @ 30 Hz with CVT-RB blanking (2 pixels per 146 MHz TMDS clock)
[[Generalized Timing Formula]] (GTF) is a [[VESA]] standard which can easily be calculated with the [[Linux]] gtf utility.
====Digital data encoding====
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====Display power management====
The DVI specification includes signaling for reducing power consumption.
===Analog===
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==DVI and HDMI compatibility==
[[HDMI]] is a newer digital audio/video interface developed and promoted by the consumer [[electronics industry]]. DVI and HDMI have the same electrical specifications for their TMDS and VESA/DDC twisted pairs.
* HDMI lacks VGA compatibility and does not include analog signals.
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* HDMI sources differentiate between legacy DVI displays and HDMI-capable displays by reading the display's [[EDID]] block.
To promote interoperability between DVI-D and HDMI devices, HDMI source components and displays support DVI-D signalling.
Some DVI-D sources use non-standard extensions to output HDMI signals including audio (e.g. [[Radeon R600|ATI 3000-series]] and [[GeForce 200 Series|NVIDIA GTX 200-series]]).<ref name="HDMI2006SpecsAppC">{{cite news |title=HDMI Specification 1.3a Appendix C |publisher=HDMI Licensing, LLC. |url=http://www.hdmi.org |format=PDF |date=2006-11-10 |access-date=2009-11-18}}</ref> Some multimedia displays use a DVI to HDMI adapter to input the HDMI signal with audio. Exact capabilities vary by video card specifications.
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