An input device is a peripheral device that converts symbols that people understand into bits that computers can process. An input device includes a keyboard, a terminal, a touch screen, a mouse, a scanner, etc.

Keyboard Entry

In keyboard entry, a user types characters, numerics and special symbols using a keyboard. The input usually appears on a monitor. A keyboard entry might be the most common way to input data.

Keyboards

A keyboard is a device used to encode data by key depression, which enters information into a system. The keyboard converts alphabets and numbers, and other special symbols into electrical signals that processor can understand and process. These signals are sent to the computer's CPU. There are three different layouts.

• QWERTY: This is a standard keyboard layout. QWERTY indicates the arrangement of the upper left corner six letters in the first row of the alphabetic keys.

• AZERTY: This is a keyboard layout that is similar to the QWERTY layout and some European countries use this keyboard. This layout is slightly modified from the QWERTY keyboard.

• Dvorak: This is another keyboard layout modified greatly from a standard layout. The keyboard is devised to increase typing speed by placing frequently used keys more naturally. In the past, mechanical jams were a problem in typing. Thus, the standard keyboard layout was designed to limit typing speed. Interesting, huh?

Terminals

A terminal is an input/output device that usually includes a keyboard for input, a video display for output, and a communications link to send and receive information. There are three different types:

• Dumb Terminal: This is an input/output terminal that does not have a capability of processing. It only enters and receives data without processing.

• Smart Terminal: This terminal has some processing capability. It has a small memory. It performs some editing of data before sending them to a main computer.

• Intelligent Terminal: This is a terminal that has a full processing capability. The terminal has a processing unit, primary storage. It may or may not have local storage. Recently, most intelligent terminals have local disk. An intelligent terminal is actually a microcomputer with communications capability.

Direct input is a data entry form that does not use a keyboard to input data. Today, more data and instructions are entered a CPU of microcomputers directly using direct input devices used to provide a more natural user interface. These entry devices reduce users' typing errors. While direct input is an advanced fourth generation data entry form, voice input (speech input) is the mode of next generation input technology. There are many forms of direct input devices:

• Mouse
  
• Touch screen
  
• Light Pen
  
• Graphics Tablet
  
• Scanner
  
• Bar-code readers
  
• Magnetic Entry
  
• Voice-Input Devices

Mouse

An object used as a pointing and drawing device. The mouse usually has a ball and buttons and is connected to the system unit through serial port. As a mouse is rolled across the flat desktop in any direction, it locates the pointer correspondingly on the screen. Then it issues commands using the selection buttons on the mouse. Many portable microcomputers such as lap-tops use trackballs instead of mice.

Touch Screen

A touch screen is a monitor screen that allows users to interact with a computer system by touching an area of the display screen. The screen is covered with a clear plastic layer that has a matrix of cells. A user touches a graphic button that displays option on the screen. Touch screens are easy to use. Thus, many kiosks use touch screens as input forms.

Light Pen

A light pen is a light-sensitive pen-like device used by pointing it at the display surface. A user brings the light pen to the desired point on the screen and presses a button, causing it to identify the current location. It is used to select options from a menu or to draw images.

Digitizer Tablet

A digitizer tablet is also called a graphics tablet or just a digitizer. The digitizer is a drawing tablet used to sketch new images or trace old drawing or photograph. The user uses a pen-like device called a cursor to draw images. Designers and architects usually use digitizers. Light pen and digitizer technologies are used for pen-based computing.

Scanner

A scanner is a device that reads spatial pattern such as images, graphics and texts, and then generates digital signals of that pattern. Converted digital data may be processed by a computer, stored in a disk, printed by a printer or displayed on a monitor. Scanners are commonly used to capture graphic images that can then be placed in a page or on any document.

Scanners usually include optical character recognition (OCR) software so that scanners can read and capture texts directly through optical scanning.

Bar Code Readers

A bar code is a specialized code represented by sets of parallel bars of varying thickness and separation. This is used for fast identification of items with an optimal scanner. The optical scanner is called a bar code reader. The bar code reader is a photoelectric scanner that read the bar code.

Magnetic Data Entry

There are two technologies in magnetic data entry. A magnetic ink character recognition (MICR) technology reads iron oxide ink preprinted or encoded on checks, deposit slips or on documents. An MICR reader electronically captures data, by first magnetizing the magnetic ink characters and then sensing the signal.
Another form of magnetic data entry is the magnetic stripe technology that makes computers read credit cards. The dark magnetic stripe on the back of credit cards is the iron oxide coating. A magnetic stripe reader reads this magnetic stripe.

Voice Input Devices

Voice input devices are also called speech- recognition devices or voice-recognition systems. This device uses a voice recognition technology that converts a user's speech into a digital code. Spoken words are first digitized and then matched against a dictionary of patterns previously stored in the computer.
Speaker-dependent systems should be trained by taking actual user's word sample before using, but speaker-independent systems can recognize only limited vocabularies. The advantage of the voice input systems is that they enable users to keep their hands free for other tasks.

Pen-Based Computing

This computing technology recognizes handwriting and has software that recognizes and digitizes handwriting and handdrawing.

Kiosks

A stand alone information delivery system that often uses a touch screen as an input device. For example, kiosks are found in an airport for users to get information on car rentals, hotel reservations and travel information.

Track ball

An input device used in graphics applications and as a mouse alternative when no flat surface is available. It is a stationary unit that contains a rolling ball that is rotated with the fingers and, correspondingly, moves the cursor on the screen.

Recent Trends

A recent trend has been the use of microcomputers as terminals. As prices of microcomputers have dropped, companies have tended to buy intelligent terminals (microcomputers) instead of dumb terminals. It is because microcomputers can work exactly like dedicated terminals with the appropriate software and communications links.