VGA is an analogue display technology which uses an HD-15 connector. This technology had a 256KB of video memory on board and it could display 16 colors at 640)(480, 640)(350, and 320×200 pixels. While using mode 13h of the VGA BIOS, 256 colors could display at 320×200 pixels. It became widely used and was popular for a long time.
In VGA-based graphics adapters, the monitors receive an analogue signal over the cable. But, in MDA, CGA, EGA, HDMI, and DVI-D, there is no analogue-to-digital conversion required. The VGA uses a dynamic palette of 256 colors, which has various shades and hues of an 18-bit palette of 262,114 colors. The VGA requires only 3 pins, one each for red, green, and blue modulated analogue color levels.