Visual Display Unit

hardware (VDU, or "video terminal", "video display

terminal", VDT, "display terminal") A device incorporating a

cathode ray tube (CRT) display, a keyboard and a serialport. A VDU usually also includes its own display

electronics which store the received data and convert it into

electrical waveforms to drive the CRT.

VDUs fall into two categories: dumb terminals and

intelligent terminals (sometimes called "programmable

terminals").

Early VDUs could only display characters in a single preset

font, and these were confined to being layed out in a

rectangular grid, reproducing the functionality of the

paper-based teletypes they were designed to replace.

Later models added graphics facilities but were still driven

via serial communications, typically with several VDUs

attached to a single multi-user computer. This contrasts with

the much faster single bitmap displays integrated into most

modern single-user personal computers and workstations.

The term "Display Screen Equipment" (DSE) is used almost

exclusively in connection with the health and safety issues

concerning VDUs.

Working with VDUs - UK Heath and Safety Executive.

(2002-11-09)