PC Video Monitor Buses


This is a subdivision of common PC Video Monitor buses. Video Buses designed to operate with Personal Computers [PC's] are listed here. This page lists all the types of video interfaces which operate over a cable, from the Personal Computer [PC] to a Monitor. Video interface Bus types that operate over a back plane are listed on their own pages. Types of Video interfaces that operate over the MotherBoard include the AGP Bus, PCI Bus, PCI Express Bus, the ISA/AT Bus and the Versa Local Bus. Video connections which may only be found on an Apple computer are listed on the Apple Monitor page. A few SGI pinout table links are also included. The SGI links are listed at the bottom of the page, but all links point to pinout tables. Back to the main Interface Bus page.

CGA [Color Graphics Adapter]: The CGA standard [1981] supports several different modes; the highest quality text mode is 80x25 characters in 16 colors. The monitors are digital with a composite signal which is at TTL logic levels; Hs, Vs, and RGBI all at TTL logic levels. This is an OBSOLETE bus. The cable uses a 9-Pin D connector. The pinout follows:
Pin 1: GND, Pin 2: GND, Pin 3: Red, Pin 4: Green, Pin 5: Blue, Pin 6: Intensity, Pin 7: NC, Pin 8: Horizontal Sync, Pin 9: Vertical Sync. GND = Ground, NC = No Connect

DFP [Digital Flat Panel] connector pinout and signal names. The DFP specification was released in 1999 and was intended as an interim standard between the VGA interface and the P and D connector.

DISM [Digital Interface Standards for Monitors] released as JEIDA-59-1999. DISM accepts all three competing technologies, TMDS, LVDS and GVIF, as its standard data-transfer formats.
The group of proposed standards includes 6 different digital interfaces with 14, 20, 26 and 36-pin [MDR] connectors.

DisplayPort : Could be the replacement to both the DVI and VGA interfaces on the PC [released in 2007].

DVI [Digital Visual Interface]: A digital rather then an analog interface which is better then any analog only interface listed on this page.

EGA [Enhanced Graphics Adapter]: This EGA standard [1984] offered improved resolutions and more colors than CGA. EGA allowed graphical output up to 16 colors (chosen from a palette of 64) at screen resolutions of 640x350, or 80x25 text with 16 colors, all at a refresh rate of 60 Hz. The monitors have a digital interface. OBSOLETE bus. The link provides the Pin out for the connector. The cable uses a 9-Pin D connector.

EVC [Enhanced Video Connector] connector pin-out and signal names

FPDI [Flat Panel Display Interface] describes the electrical layer, logical layer, and connector interface between flat panel displays and display controllers in an integrated environment.
Also FPDI-1, used with VGA and SVGA [800 x 600]. Followed by FPDI-2

MDA [Monochrome Display Adapter]: established by IBM as part of the original Personal Computer [PC]. MDA is a monochrome-only, text-only standard, allowing text display at 80x25 characters.
This bus is OBSOLETE. The cable uses a 9-Pin D connector. The pinout follows:
Pin 1: GND, Pin 2: GND, Pin 3: NC, Pin 4: NC, Pin 5: NC, Pin 6: Intensity, Pin 7: Mono Video, Pin 8: Horizontal Sync, Pin 9: Vertical Sync. GND = Ground, NC = No Connect

MCGA [Multicolor Graphics Array]: Video interface found on PS/2 computers over a 9-pin D connector. This is an OBSOLETE bus.

OpenLDI [Open LVDS Display Interface]: was released in 1999 and was based on the LVDS interface using a 36-pin MDR connector. Open LDI included USB and DDC/EDID support. OpenLDI was used on laptops and connected the LCD monitor to the main board.
Refer to the OpenLDI Pin Out as found on an SGI computer.

PGA [Professional Graphics Adapter]: The PGA standard appeared in 1984 as an analog interface. This is an OBSOLETE bus. The cable uses a 9-Pin D connector. The pinout follows:
Pin 1: Red, Pin 2: Green, Pin 3: Blue, Pin 4: Composite Sync, Pin 5: Mode Control, Pin 6: red Ground, Pin 7: Green Ground, Pin 8: Blue Ground, Pin 9: Ground

P&D [Plug and Display Interface] describes the Physical, Electrical layer and Logical layer, and connector interface between Monitors and display controllers. This interface combines a number of different electrical interfaces into one system, to include USB and/or a IEEE 1394, I2C, and Analog video signals. Cable length is not defined.

UDI {The Unified Display Interface [UDI] was a standard for high-speed, high-resolution digital displays. It started as a replacement to the DVI connection on PCs and as a complement to HDMI connections for A/V interfaces. However after the release of the first few revisions [2005/2006] of the standard [before any products were developed] support for the standard was dropped [2007]. UDI was a lower cost version of the DVI/HDMI video interfaces. After the initial standard was released in 2005 and upgraded in 2006, support for the interface was dropped in 2007 in favor of the DisplayPort interface. It would appear that support was transferred to the DisplayPort Interface. No products were ever produced using the UDI specification and as of 2010 appears to be unsupported.}

VGA [Video Graphics Array]: VGA [1987] is a superset of EGA, incorporating all EGA modes. Older displays sent digital signals to the monitor, while VGA (and later) send analog signals.
This change was necessary to allow for more color precision. Resolution of 640 x 480.

SVGA [Super VGA] offers more colors and resolutions, but really does not exist as a single standard. The primary standard refers to the BIOS, and how the computer talks to the monitor. VESA Display Data Channel [DDC] is a VESA standard that defines how to read certain pins in a standard SVGA monitor to query the monitor's capabilities. Resolution of 800 x 600.

Video Resolutions
Interface Detail Resolution
WQXGA: Wide Quad eXtended Graphics Array 2560 x 1600
QXGA Extended Graphics Array 2048 x 1536
WUXGA: Wide UXGA 1920 x 1200
UXGA Ultra Extended Graphics Array] 1600 x 1200
XSXGA: - 1680 x 1050
WXGA Wide Extended Graphics Array 1366 x 768
SXGA Super Extended Graphics Array 1280 x 1024
XGA: Extended Graphics Array 1024 x 768

VMChannel [VESA Media Channel] describes a hardware interface for desktop multimedia systems. The VMChannel is a multiple master, multiple drop, clock synchronous interface designed for concurrent pixel data streams. VMChannel enables the real time flow of uncompressed multimedia pixels in a bidirectional fashion between multiple video adapters.

VAFC; VESA Advanced Feature Connector. A point-to-point interface between a display adaptor and video board. 32-bits at 150MBps over an 80-pin cable.

VFC; VGA Feature Connector. A point-to-point interface between two video boards. 8-bits at 40MBps over an 26-pin cable via a card edge connector.

VSIS; Video Signal Standard, from VESA

XGA [Extended Graphics Array]: IBM introduced [1990] the XGA interface as a successor to its 8514/A display. Resolution of 1024 x 760.
The cable uses a 15-Pin HD connector [High density].

13W3 interface normally found with Sun Computers.
The term really refers to a style of connector.

SGI Bus [Silicon Graphics Inc] produced work-stations, a few pinout tables are listed on this page.
9-Pin Digital Video
DB-15 Video Interface
Flat Panel Digital Video & SGI O2Cam Video Interface Pinout

All of the different interface Video bus pages listed above deal with layer 1 [Physical, Electrical and Mechanical Layer] of the OSI protocol stack.
Many pages also reference layer 2; the Data Link Layer [which provide bit/byte stuffing, checksum, Protocols..].

Additional Listings: Video Cable Manufacturers, or Video Style Connectors

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Modified 2/26/12
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