The Color Graphics Adapter (CGA), originally also called the Color / Graphics Adapter or IBM Color / Graphics Monitor Adapter, introduced in 1981, was IBM ’s first color graphics card, and the first color computer display standard for the IBM PC.
CGA Monitor
The standard IBM CGA graphics card was equipped with 16 kilobytes of video memory, and could be connected either to a NTSC-compatible monitor or television via an RCA jack, or to a dedicated 4-bit “RGBI” interface CRT monitor, such as the IBM 5153 color display.
Built around the Motorola MC6845 display controller, the CGA card featured several graphics and text modes. The highest resolution of any mode was 640×200, and the highest color depth supported was 4-bit (16 colors).
CGA Connector
9pin CGA
| Pin | Function |
| 1 | Ground |
| 2 | Ground |
| 3 | Red |
| 4 | Green |
| 5 | Blue |
| 6 | Intensity |
| 7 | Reserved |
| 8 | Horizontal Sync |
| 9 | Vertical Sync |
CGA Signal
| Type | Digital, TTL |
| Resolution | 640h × 200v, 320h × 200v |
| H-freq | 15.75 kHz |
| V-freq | 60 Hz |
| Colors | 16 |
