(VDU, or "video terminal", "video display terminal", VDT, "display terminal") A device incorporating a cathode ray tube
(CRT) display, a keyboard and a serial port
. 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
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 (http://hse.gov.uk/pubns/indg36.pdf).