Terminals

Source: http://www.barcodeman.com/altek/mux/mxcept2a.png (accessed August 6, 2009)

How does it work?

Computer terminal enables a computer to receive and deliver data. It varies depending on the type of data that it handles. The early terminal has a typewriter keyboard for input and a typewriting printing element to access alphanumeric output. The more recent variations have stylus or pressure-sensitive panel for inputs and different television-like screens for outputs. These screens show lines that display alphanumeric or graphic images that are used by architects and engineers as design tools. The modern terminals are used by stores as checkout systems that produce printed receipts and use laser scanners to read the bar codes on packages, and automatic teller machines in banks.

Source: http://www.encyclopedia.com/topic/computer_terminal.aspx (accessed August 6, 2009)

Who are the leading providers of this device?

The said device could be purchased from:
1. Symbol Technologies , Inc.
Holtsville, New York

2. Research In Motion Limited
Waterloo, Ontario, Canada

3. Hewlett-Packard Company
Palo Alto, California

4. Fujitsu Limited
Tokyo, Japan

5. Psion Teklogix Inc
Mississauga, Ontario, Canada

Source: http://www.zoominfo.co (accessed August 4, 2009)

What are the different types of terminals?

1. Text terminal
Text terminal, which is otherwise known as terminal, is a computer interface that use text for entry and display. It cooperates with the terminal emulator to communicate with the modern graphical user interface.

2. Dumb terminal
Dumb terminal interpret a limited number of control codes (CR, LF etc.) but does not have the ability to process special escape sequences that perform functions such as clearing a line, clearing the screen, or controlling cursor position. It is sometimes called glass teletypes since it has the same limited functionality as does a mechanical teletype.

3. Graphic terminals
Graphical terminal, as the name implies, can display images as well as text on the screen. It is divided into vector-mode terminals and raster mode.

Source: http://en.wikipedia.org/wiki/Computer_terminal#Text_terminals (accessed August 4, 2009)

By Clara Obmerga

Terminals are used for entering and displaying data information from a computer or computing system. If the device has a significant local programmable data processing capability, it is called a "smart terminal" or fat client whereas when the terminal’s processing power is dependent on the host computer it is called a thin client. The device also allows the computer to connect some terminal server, usually a powerful computer, and do all work there, outside own memory and system resources. A personal computer can run software that emulates the function of a terminal, sometimes allowing concurrent use of local programs and access to a distant host system.

KINDS OF TERMINALS
Text terminals, also known as text console, is a serial computer interface for entering and displaying information, where the information is presented as a collection of pre-selected formed characters . There are different types of text terminals which include the system used to operate a computer. Modern computers have a built-in keyboard and display for the console. Some Unix-like operating systems such as Linux, FreeBSD and Mac OS X have virtual consoles to provide several text terminals on a single computer. Another type is the terminal emulator is a computer program that allows text terminals to coexist with modern graphical user interfaces such as the Win32 console. Special terminal emulators are those that are used with modems .
Dumb Terminals, also known as glass teletypes, have limited functionality since they can only interpret a certain number of control codes and do not have the capacity to process special escape sequences that perform functions such as clearing a line, clearing the screen, or controlling cursor position. On the other hand, smart or intelligent terminals are those that also have the ability to process escape sequences, in particular the VT52, VT100 or ANSI escape sequences.

Graphical Terminals, which is the most used terminal today, have the ability to display images as well as text. They are divided into vector mode and raster mode terminals. Vector mode displays are no longer used because of the limited concurrent lines that can be displayed at one time. Today, all modern graphic displays are raster-mode which uses the picture scanning techniques used for television. Modern graphic terminals allow display of colored images and of different size, color and font of the text.

By PamSee