Following are the ways monitors have interfaced with computers since the advent of IBM's PS/2 line in 1987.
Video Interfaces
CGA and EGA were the first PC interfaces. They were digital and lasted seven years until analog VGA followed. VGA was superseded by DVI, which was digital again. Then came HDMI and DisplayPort. See
CGA,
EGA,
VGA,
DVI,
HDMI and
DisplayPort.