Digital Visual Interface
Digital Visual Interface (DVI) is a video display interface developed by the Digital Display Working Group (DDWG). The digital interface is used to connect a video source, such as a video display controller, to a display device, such as a computer monitor. It was developed with the intention of creating an industry standard for the transfer of uncompressed digital video content.
"DVI" redirects here. For other uses, see DVI (disambiguation).Type
Digital computer video connector
April 1999
1999–present
Yes
Yes
DVI-D Single Link: 19
DVI-D Dual Link: 25
DVI-I Single Link: 23
DVI-I Dual Link: 29
DVI-A: 11
DVI-M1-DA: 35
(Single link) 3.96 Gbit/s
(Dual link) 7.92 Gbit/s
1
3 × transition minimized differential signaling data and clock
TMDS data 2−
TMDS data 2+
TMDS data 2/4 shield
TMDS data 4−
TMDS data 4+
DDC clock
DDC data
Analog vertical sync
TMDS data 1−
TMDS data 1+
TMDS data 1/3 shield
TMDS data 3−
TMDS data 3+
+5 V
Ground
Hot plug detect
TMDS data 0−
TMDS data 0+
TMDS data 0/5 shield
TMDS data 5−
TMDS data 5+
TMDS clock shield
TMDS clock+
TMDS clock−
Analog red
Analog green
Analog blue
Analog horizontal sync
Analog ground
DVI devices manufactured as DVI-I have support for analog connections, and are compatible with the analog VGA interface[1] 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 Digital Flat Panel (DFP).[2] Although DVI is predominantly associated with computers, it is sometimes used in other consumer electronics such as television sets and DVD players.
History[edit]
An earlier attempt to promulgate an updated standard to the analog VGA connector was made by the Video Electronics Standards Association (VESA) in 1994 and 1995, with the Enhanced Video Connector (EVC), which was intended to consolidate cables between the computer and monitor.[3][4] EVC used a 35-pin Molex MicroCross connector and carried analog video (input and output), analog stereo audio (input and output), and data (via USB and FireWire). At the same time, with the increasing availability of digital flat-panel displays, the priority shifted to digital video transmission, which would remove the extra analog/digital conversion steps required for VGA and EVC;[5]: 5–6 the EVC connector was reused by VESA,[6] which released the Plug & Display (P&D) standard in 1997.[3] P&D offered single-link TMDS digital video with, as an option, analog video output and data (USB and FireWire), using a 35-pin MicroCross connector similar to EVC; the analog audio and video input lines from EVC were repurposed to carry digital video for P&D.[5]: 4 [7]: §1.3.3
Because P&D was a physically large, expensive connector, a consortium of companies developed the DFP standard (1999), which was focused solely on digital video transmission using a 20-pin micro ribbon connector and omitted the analog video and data capabilities of P&D.[4]: 3 [5]: 4 DVI instead chose to strip just the data functions from P&D, using a 29-pin MicroCross connector to carry digital and analog video.[8] Critically, DVI allows dual-link TMDS signals,[9] meaning it supports higher resolutions than the single-link P&D and DFP connectors, which led to its successful adoption as an industry standard. Compatibility of DVI with P&D and DFP is accomplished typically through passive adapters that provide appropriate physical interfaces, as all three standards use the same DDC/EDID handshaking protocols and TMDS digital video signals.[10]: §1.3.7
DVI made its way into products starting in 1999. One of the first DVI monitors was Apple's original Cinema Display, which launched in 1999.
The DVI connector on a device is given one of three names, depending on which signals it implements:
Most DVI connector types—the exception is DVI-A—have pins that pass digital video signals. These come in two varieties: single link and dual link. Single link DVI employs a single transmitter with a TMDS clock up to 165 MHz that supports resolutions up to 1920 × 1200 at 60 Hz. Dual link DVI adds six pins, at the center of the connector, for a second transmitter increasing the bandwidth and supporting resolutions up to 2560 × 1600 at 60 Hz.[11] A connector with these additional pins is sometimes referred to as DVI-DL (dual link). Dual link should not be confused with dual display (also known as dual head), which is a configuration consisting of a single computer connected to two monitors, sometimes using a DMS-59 connector for two single link DVI connections.
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 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.[12]
DVI is the only widespread video standard that includes analog and digital transmission in the same connector.[13] Competing standards are exclusively digital: these include a system using low-voltage differential signaling (LVDS), known by its proprietary names FPD-Link (flat-panel display) and FLATLINK; and its successors, the LVDS Display Interface (LDI) and OpenLDI.
Some DVD players, HDTV sets, and video projectors 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).
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. However HDMI and DVI differ in several key ways.
To promote interoperability between DVI-D and HDMI devices, HDMI source components and displays support DVI-D signalling. For example, an HDMI display can be driven by a DVI-D source because HDMI and DVI-D both define an overlapping minimum set of supported resolutions and frame buffer formats.
Some DVI-D sources use non-standard extensions to output HDMI signals including audio (e.g. ATI 3000-series and NVIDIA GTX 200-series).[17] Some multimedia displays use a DVI to HDMI adapter to input the HDMI signal with audio. Exact capabilities vary by video card specifications.
In the reverse scenario, a DVI display that lacks optional support for HDCP might be unable to display protected content even though it is otherwise compatible with the HDMI source. Features specific to HDMI such as remote control, audio transport, xvYCC and deep color are not usable in devices that support only DVI signals. HDCP compatibility between source and destination devices is subject to manufacturer specifications for each device.
In December 2010, Intel, AMD, and several computer and display manufacturers announced they would stop supporting DVI-I, VGA and LVDS-technologies from 2013/2015, and instead speed up adoption of DisplayPort and HDMI.[18][19] They also stated: "Legacy interfaces such as VGA, DVI and LVDS have not kept pace, and newer standards such as DisplayPort and HDMI clearly provide the best connectivity options moving forward. In our opinion, DisplayPort 1.2 is the future interface for PC monitors, along with HDMI 1.4a for TV connectivity".