TFT Guide Part 3 - Digital Interfaces

Comparison And Summary

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StandardP&DPlug&DisplayDFPDigital Flat PanelDVIDigital Visual Interface
OwnerVESA (V ideo E lectronics S tandards O rganization)DFP Group (D igital F lat P anel Group) and later VESADDWG (D igital D isplay W orking G roup)
Revision / Date1.0 / Jun 06, 19971.0 / Feb 14, 19991.0 / Apr 02, 1999
Workgroup leaderVESACompaqIntel
CompatibilityOwn standardP&D compatible (adapter possible)P&D and DFP compatible (adapter possible)
Transfer protocolTMDS (PanelLink)TMDS (PanelLink)TMDS (PanelLink)
Max. pixel rate (Dot Clock)165 MHz x 1165 MHz x 1165 MHz x 2
Max. number of channels3 channels (single link)3 channels (single link)6 channels (dual link)
Color depths12 or 24 bit12 or 24 bit12 or 24 bit
Max. ResolutionSXGA (1280 x 1024)SXGA (1280 x 1024)HDTV (1920 x 1080)
Optional transfer of other signals possible using the same connectorAnalog VESA video, USB, IEEE 1394-1995No, only digital videoAnalog VESA video
Digital ConnectorP&D-D (30 pin)MDR20 (20 pin)DVI-V (24 pin)
Analog/Digital combination connectorP&D-A/D (30 + 4 pin)NoDVI-I (24 + 4 pin)
Connector width40.6 mm33.4 mm37.0 mm

Table 2: Comparison of the three most important digital interfaces.

If you compare P&D, DFP and DVI carefully, the conclusion is fairly simple: The expensive Plug&Display standard is practically obsolete and DFP limits the resolution to 1280 x 1024 pixels and only allows the connection of digital TFT displays. This means that monitors with analog VGA connectors can't be connected because a digital-analog connector is far too complicated). Matrox, ATI and Number Nine have already announced products with DVI connectors. DVI uses not only the same protocol as P&D and DFP, it is also electrically compatible. This means that adapters are possible to use all three digital standards, although the maximum resolution may not exceed 1280 x 1024 pixels. This would require a second link (dual link ), which, of course, only DVI incorporates. Graphic board manufacturer Number Nine has eccectively demonstrated the inherent level of 'interconnectivity' with its SR9 card that is based on a Savage4 chip from S3 . The user can select which of the three connections - P&D, DFP or DVI - he wishes to use as an optional extra. In our opinion, the future belongs to the Digital Visual Interface (DVI) interface. DVI not only allows high resolutions, it also enables the connection of analog devices (using an adapter if necessary). Beyond that, DVI has enough support from the industry to prevail on a long-term basis.