Tech Info - PC Monitor Connectors

The beginnings of this section on connection of monitors and video equipment to a 'common or garden' x86 type PCs.

• CGA Monitor using a DB9 style connector
• ECA Monitor using a DB9 style connector
• VGA Monitor using DB9 or 15 style connector

Note: The DB9 connector diagrams shown here reference the TIA/EIA - 574 standard which is not strictly correct as it defines both pin numbers and signals. In the context of this section we use it to define pin numbers only.

CGA Monitor (DB9)

DB9 Pin Name Function/Notes 1 GND Ground 2 GND Ground 3 RED Red Video 4 GREEN Green Video 5 BLUE Blue Video 6 Intensity Color Intensity 7 RESERVED Reserved 8 HSYNC Horizontal Sync. 9 VSYNC Vertical Sync.

EGA Monitor (DB9)

DB9 Pin Name Function/Notes 1 GND Ground 2 SRED Secondary Red Video 3 PRED Primary Red Video 4 PGREEN Primary Green Video 5 PBLUE Primary Blue Video 6 SGREEN Secondary Green Video 7 SBLUE Secondary Green Video 8 HSYNC Horizontal Sync. 9 VSYNC Vertical Sync.

VGA Monitor (DB15 & DB9)

The VGA connector can use a classic DB9 connector or (more commonly today) a DB15 style connector. The Female end of this connector is at the Host/PC. Interface defined by Video Electronic Standards Association (VESA)

DB15 Format

Pin No Name Function/Notes VESA DDC Notes 1 RED * Red Video     2 GREEN * Green Video     3 BLUE * Blue Video     4 ID2 Monitor ID Bit2     5 GND Vertical Sync.     6 RGND Red Ground (Return)     7 GGND Green Ground (Return)     8 BGND Blue Ground (Return)     9 NC No Connect     10 SGND Sync Ground (Return)     11 ID1 Monitor ID bit 1     12 ID0 Monitor ID bit 0 DDC Serial Data 13 HSYNC Horizontal (or Composite) Sync     14 VSYNC Vertical Sync     15 NC No Connect DDC Serial Clock

Notes:

1. Older Implementations used the ID0-2 bits (Pins 4, 12 and 13) to denote limited video characteristics (mono, color and resolution). Modern Plug n' Play monitors provide enhanced data using the VESA serial DDC interface (Pins 12 and 15).

DB9 Format

DB9 Pin Name Function/Notes 1 RED Red Video 2 GREEN Green Video 3 BLUE Blue Video 4 HSYNC Horizontal Sync. 5 VSYNC Vertical Sync. 6 RGND Red Ground (Return) 7 GGND Green Ground (Return) 8 BGND Blue Ground (Return) 9 SGND Sync Ground

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