| Video Graphics Specifications |
| Creator : | IBM |
| Year Introduced : | 1981 |
| Video Standard : | MDA - Monochrome Display Adapter |
| Horizontal Frequency : | 18.4 kHz |
| Vertical Frequency : | 50 Hz |
| Video RAM : | 4K |
| Maximum Colors : | 1 |
| Maximum Resolution : | 720x350 |
| Starting Address : | B0000 |
| Connector Type : | DB9 |
| Video Signals : | 2 TTL |
| Status : | Obsolete |
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| Monochrome Display Adapter |
The monochrome display adapter (MDA) was the the first display adapter available. It is designed to work with a monochrome transistor-transistor logic (TTL) monitor. It is a text-only system that cannot display graphics or color. The MDA uses a 9 x 14 dot character box that provides clean sharp characters. Because most of the software packages developed today, even word processing and spreadsheets, use graphics to some extent, the MDA is generally considered obsolete.
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| DB-9 pins for MDA |
|---|
| Pin | Description |
|---|
| 1 | Signal ground |
| 2 | Signal ground |
| 3 | Not used |
| 4 | Not used |
| 5 | Not used |
| 6 | Signal intensity |
| 7 | Video signal |
| 8 | Horizontal sync |
| 9 | Vertical sync |
| C A U T I O N |
| Never run your monitor out of spec. If your display is screwed up, there's a good chance that the frequencies are out, so turn off the monitor! |
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