A monochrome monitor is a type of computer monitor in which computer text and images are displayed in varying tones of only one color, as opposed to a color monitor that can display text and images in multiple colors. They were very common in the early days of computing, from the 1960s through the 1980s, before color monitors became widely commercially available. They are still widely used in applications such as computerized cash register systems, owing to the age of many registers. Green screen was the common name for a monochrome monitor using a green "P1" phosphor screen; the term is often misused to refer to any block mode display terminal, regardless of color, e.g., IBM 3279, 3290.
An IBM computer with a green monochrome monitor
Early Nixdorf computer with an amber monitor
An open Schneider MM12 from 1988. It uses a GoldStar Type 310KGLA amber tube.
A computer monitor is an output device that displays information in pictorial or textual form. A discrete monitor comprises a visual display, support electronics, power supply, housing, electrical connectors, and external user controls.
Eizo ColorEdge monitor with screen hood
Hydraulic arm monitor stand, connected via VESA mount holes
A fixed 19-inch (48 cm), 4:3 rack mount LCD monitor
A 1U stowable clamshell 19-inch (48 cm), 4:3 rack mount LCD monitor with keyboard