UNIT – IV
Input Devices: Keyboard, Mouse, joystick, MICR, OCR, Barcoding, Speech
Output Devices: Printers, Plotter, VDU, Graphic Display Devices.
INPUT DEVICES
The computer will be of no use unless it is able to communicate with the outsideworld.
Input/Output devices are required for users to communicate with the computer.
In simple terms, input devices bring information INTO the computer and outputd evices bring
information OUT of a computer system. These input/output devices are also known as
peripherals since they surround the CPU and memory of a computer system. Input devices
are hardware devices that allow data to be entered into a computer.
The computer will be of no use if it is not communicating with the external world. Thus, a
computer must have a system to receive information from the outside world and must be able
to communicate results to the external world. Thus, a computer consists of input/output
devices. Input and output devices can also be written as I/O devices.
Input and output devices of a computer system are the devices that connect you to computer.
Input devices let you to transfer data and user command into the computer system. I/O
devices are used to interact with the computer system. For example, you can type in data by
using a keyboard, or you can input data in picture form by using a scanner in computer
system.
An input device presents data to the processing unit in a machine-readable form.Although the
keyboard is a common input device for a small computer, a systemmay also support various
other input devices such as Optical CharacterRecognition (OCR), Magnetic Ink Character
Recognition (MICR), mark sense reader, etc.
Manual Input devices: Data is input into the computer by hand. Manual input devices
require humans to do most of the work needed to get data into the system. (eg.) Keyboard,
Mouse, Tracker ball, Joystick, graphics tablet, digital camera, Webcam, microphone, touch
screen, chip and pin
Direct Input devices (automatic input devices): Data is input into the computer directly by
a machine or device. Direct input devices do not require much human interaction to get their
data into a computer system. (eg.) Barcode scanner, Magnetic stripe reader, OMR reader,
OCR reader, biometric scanner, Sensor.
1 | III UNIT: NME -1: INFORMATION TECHNOLOGY
,KEY BOARD
The keyboard is the most common and widely used input device. It is made up of buttons
called 'keys'. The keys are arranged into sections:
• Alphabet keys
• Function or F keys (F1, F2, F3)
• Numeric keys (one set above the alphabet keys and a numeric keypad on the right)
• Arrow keys
• Command keys (insert, delete, home, end, page up/down)
Keyboards are used to input Text, numbers and instructions into the computer. Most
keyboards use a QWERTY key layout. This name comes from the first six letters on the top
row of the alphabet keys.
Special keyboards called “Ergonomic keyboards” have built-in-hand-rest which prevents
health issues such as RSI (Repetitive Strain Injury).Ergonomic keyboards have natural shape
to reduce stress on wrist and hands.
A concept keyboard is a specialized keyboard with no pre-set keys. It relies on a touch
sensitive screen with the key or overlay displayed on the screen. Each key can be
programmed with a wide range of different functions. The overlay is often used as a quick
and easy way to input items with without needing to type anything or use a mouse. If you go
to a fast food restaurant, the assistant will normally be using a concept keyboard. Pictures and
icons can replace words and means that the assistant can quickly enter the order without
having to use a keyboard.
Numeric keypads are used for entering numbers into a computer system. Some numeric
keypads allow you to enter simple text and symbols. Numeric keypads are found in ATM
(Automatic Teller Machines), telephones and chip and pin device. Electronic point of sale
(EPOS) terminals has numeric keypads in case the barcode reader fails.
Uses of keyboard:
• Keyboards are used to enter text, numbers and instructions into applications like Word and
Excel.
• Keyboards can also be used to enter commands(keyboard shortcuts) into the computer
Advantages of keyboards:
1. Enable fast entry of data.
2. Most computers come with a keyboard supplied
3. People need very little training to use keyboard.
2 | III UNIT: NME -1: INFORMATION TECHNOLOGY
, Disadvantages of keyboards:
1. Keyboards are large and can take up a lot of desk space.
2. Keyboards are not suitable for creating diagrams.
3. Excessive use can lead to health problems such as repetitive strain injury (R.S.I.)
4. Entering data is slow compared to automatic methods. For example a barcode scanner will
input data into the computer almost instantly.
Alphanumeric Keypad
It consists of keys for English alphabets, 0 to 9 numbers, and special characters like +
− / * ( ) etc.
Function Keys
There are twelve function keys labeled F1, F2, F3… F12. The functions assigned to these
keys differ from one software package to another. These keys are also user programmable
keys.
Special-function Keys
These keys have special functions assigned to them and can be used only for those specific
purposes. Functions of some of the important keys are defined below.
Enter
It is similar to the ‘return’ key of the typewriter and is used to execute a command or
program.
Spacebar
It is used to enter a space at the current cursor location.
Backspace
This key is used to move the cursor one position to the left and also delete the character in
that position.
Delete
It is used to delete the character at the cursor position.
Insert
Insert key is used to toggle between insert and overwrite mode during data entry.
Shift
This key is used to type capital letters when pressed along with an alphabet key. Also used to
type the special characters located on the upper-side of a key that has two
Characters defined on the same key.
3 | III UNIT: NME -1: INFORMATION TECHNOLOGY
Input Devices: Keyboard, Mouse, joystick, MICR, OCR, Barcoding, Speech
Output Devices: Printers, Plotter, VDU, Graphic Display Devices.
INPUT DEVICES
The computer will be of no use unless it is able to communicate with the outsideworld.
Input/Output devices are required for users to communicate with the computer.
In simple terms, input devices bring information INTO the computer and outputd evices bring
information OUT of a computer system. These input/output devices are also known as
peripherals since they surround the CPU and memory of a computer system. Input devices
are hardware devices that allow data to be entered into a computer.
The computer will be of no use if it is not communicating with the external world. Thus, a
computer must have a system to receive information from the outside world and must be able
to communicate results to the external world. Thus, a computer consists of input/output
devices. Input and output devices can also be written as I/O devices.
Input and output devices of a computer system are the devices that connect you to computer.
Input devices let you to transfer data and user command into the computer system. I/O
devices are used to interact with the computer system. For example, you can type in data by
using a keyboard, or you can input data in picture form by using a scanner in computer
system.
An input device presents data to the processing unit in a machine-readable form.Although the
keyboard is a common input device for a small computer, a systemmay also support various
other input devices such as Optical CharacterRecognition (OCR), Magnetic Ink Character
Recognition (MICR), mark sense reader, etc.
Manual Input devices: Data is input into the computer by hand. Manual input devices
require humans to do most of the work needed to get data into the system. (eg.) Keyboard,
Mouse, Tracker ball, Joystick, graphics tablet, digital camera, Webcam, microphone, touch
screen, chip and pin
Direct Input devices (automatic input devices): Data is input into the computer directly by
a machine or device. Direct input devices do not require much human interaction to get their
data into a computer system. (eg.) Barcode scanner, Magnetic stripe reader, OMR reader,
OCR reader, biometric scanner, Sensor.
1 | III UNIT: NME -1: INFORMATION TECHNOLOGY
,KEY BOARD
The keyboard is the most common and widely used input device. It is made up of buttons
called 'keys'. The keys are arranged into sections:
• Alphabet keys
• Function or F keys (F1, F2, F3)
• Numeric keys (one set above the alphabet keys and a numeric keypad on the right)
• Arrow keys
• Command keys (insert, delete, home, end, page up/down)
Keyboards are used to input Text, numbers and instructions into the computer. Most
keyboards use a QWERTY key layout. This name comes from the first six letters on the top
row of the alphabet keys.
Special keyboards called “Ergonomic keyboards” have built-in-hand-rest which prevents
health issues such as RSI (Repetitive Strain Injury).Ergonomic keyboards have natural shape
to reduce stress on wrist and hands.
A concept keyboard is a specialized keyboard with no pre-set keys. It relies on a touch
sensitive screen with the key or overlay displayed on the screen. Each key can be
programmed with a wide range of different functions. The overlay is often used as a quick
and easy way to input items with without needing to type anything or use a mouse. If you go
to a fast food restaurant, the assistant will normally be using a concept keyboard. Pictures and
icons can replace words and means that the assistant can quickly enter the order without
having to use a keyboard.
Numeric keypads are used for entering numbers into a computer system. Some numeric
keypads allow you to enter simple text and symbols. Numeric keypads are found in ATM
(Automatic Teller Machines), telephones and chip and pin device. Electronic point of sale
(EPOS) terminals has numeric keypads in case the barcode reader fails.
Uses of keyboard:
• Keyboards are used to enter text, numbers and instructions into applications like Word and
Excel.
• Keyboards can also be used to enter commands(keyboard shortcuts) into the computer
Advantages of keyboards:
1. Enable fast entry of data.
2. Most computers come with a keyboard supplied
3. People need very little training to use keyboard.
2 | III UNIT: NME -1: INFORMATION TECHNOLOGY
, Disadvantages of keyboards:
1. Keyboards are large and can take up a lot of desk space.
2. Keyboards are not suitable for creating diagrams.
3. Excessive use can lead to health problems such as repetitive strain injury (R.S.I.)
4. Entering data is slow compared to automatic methods. For example a barcode scanner will
input data into the computer almost instantly.
Alphanumeric Keypad
It consists of keys for English alphabets, 0 to 9 numbers, and special characters like +
− / * ( ) etc.
Function Keys
There are twelve function keys labeled F1, F2, F3… F12. The functions assigned to these
keys differ from one software package to another. These keys are also user programmable
keys.
Special-function Keys
These keys have special functions assigned to them and can be used only for those specific
purposes. Functions of some of the important keys are defined below.
Enter
It is similar to the ‘return’ key of the typewriter and is used to execute a command or
program.
Spacebar
It is used to enter a space at the current cursor location.
Backspace
This key is used to move the cursor one position to the left and also delete the character in
that position.
Delete
It is used to delete the character at the cursor position.
Insert
Insert key is used to toggle between insert and overwrite mode during data entry.
Shift
This key is used to type capital letters when pressed along with an alphabet key. Also used to
type the special characters located on the upper-side of a key that has two
Characters defined on the same key.
3 | III UNIT: NME -1: INFORMATION TECHNOLOGY
