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In many computer installations, the most common form of terminal is the visual display unit (VDU). State and explain key features of a VDU terminal....

      

In many computer installations, the most common form of terminal is the visual display unit (VDU). State and explain key features of a VDU terminal.

  

Answers


gregory
Key features of a VDU terminal:
1.The VDU is really 2 devices: A keyboard and a screen display. The keyboard is for data input
while the screen display is for output of data.
2.Data is fed in via a keyboard which is like a typewriter keyboard, and is both passed into the
computer and displayed on the screen. The VDU can also receive and display messages from
the computer.
3.VDUs are mainly used by connecting them directly to the computer. This mode is known as
on-line data entry.
4.VDUs lack the processing capabilities of PCs and thus they are referred to as
dumbterminals.
5.VDUs were used in the past in conjunction with some other special purpose data entry
system in order to prepare data on a fast and reliable input medium. The most popular
example was the key-to-floppy-disk or key-to-diskette system. These were basically
microcomputer-based systems that took in data from the VDU and stored it on floppy disk.
6.When the VDU is used to provide a graphics display capacity e.g. for management
information systems applications, some or all of the following control devices may be
incorporated in addition to the high-definition colour monitor:
o Mouse or trackball devices
These use the rolling motion of a ball (a mouse by being rolled on a flat surface, a
trackball by being moved manually) to act as a cursor control or to move data about
the screen quickly.
o Voice Data Entry (VDE)
These employ a modified VDU and microphone to accept vocal input. The simplest
speech recognition systems may be programmed to recognize a limited number of key
words.
o Light pen and touch screen inputs
These use the VDU screen as part of the input medium. A light pen connected to the
terminal is placed against the screen, and a light sensitive device recognizes the position
by X and Y coordinates. A touch screen uses an inlaid screen to accept input through
the act of physically touching the screen.
gregorymasila answered the question on November 23, 2017 at 12:34


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