The devices that are used for direct data entry to the computer system are called source data-entry devices. The devices are also known as direct input devices. These devices provide quick and efficient way to input data into the computer.

Following is a list of commonly used source data entry devices:

Scanning Devices

Barcode Reader
Fax machine
Image scanner
Mark and character recognition devices such as;

MICR (Magnetic-Ink Character Recognition)
OMR (Optical Mark Recognition)
OCR (Optical Character Recognition)
Magnetic-Strip Card
Smart Card

1- Barcode Reader

Barcode is a unique identification code. It consists of light and dark vertical lines with spaces between them of different widths. Barcode is printed on most of the manufactured products. It represents the information about the product. Actually, the name of product, its price and other descriptions are coded as barcode. There are several bar-coding schemes or systems in use. The most popular and commonly used barcode is UPC (Universal Product Code).

Barcode reader is a special scanning device. It is used for reading (or decoding) barcode printed on the product or book. it uses laser beam to scan or read the barcode. It reads the barcode and translates it into digital signals. These signals are input to the computer for further processing. The most common type of bar code reader is the flatbed scanner. It is commonly used in super markets and departmental stores.

2- Fax machine

A fax machine is also known as facsimile transmission machine. It is used to send and receive information through telephone line. The fax machine at sending side scans information printed on paper. It converts the information into digital/analog signals and sends these signals over telephone line to a fax machine at receiving side. The fax machine at receiving side receives information in the form of digital/analog signals. It converts these signals into original form of the information and print on the paper.

Types of Fax Machine
There are two types of fax machines. These are:

Dedicated Fax Machine
Fax Modem

Dedicated Fax Machine
Dedicated fax machine is an independent normal fax machine. It can send and receive information to and from the other fax machines.
Fax Modem
Fax modem is a circuit board inside the system unit of the computer. It is used to send and receive information to and from the other computers. You can also send information directly to other fax machines. The fax modem is mostly used inside the computers to send and receive information on the Internet.

3- Image Scanner

Image scanner is also called graphic scanner. It reads text, drawing and photographs printed on the paper. It converts them into digital form and stores inside the computer for further processing.

Image scanner scans the image of information printed on paper with light. It breaks image into light and dark dots if image is black and white. In case of color image, it breaks the image into color dots. These dots are then converted into digital form. In this way, the image is stored into the computer. The technique of representing a graphic image as a matrix of dots is called raster graphics.

4- Mark and Character Recognition Devices

Mark and character recognition devices are input devices. They are used to scan (or read) information printed on the paper. These devices read the information and convert into digital signals. These signals are input to the computer for further processing. The commonly used mark and character recognition devices are described below.

(i)   MICR
      MICR stands for Magnetic-Ink Character Recognition. It is a special scanner. It reads the character printed with magnetic ink and converts them into digital signals. These signals are then input to the computer for further processing.

MICR devices are normally used in banks for processing cheques. On a cheque, the bank code, customer account number, and cheque number are printed with magnetic ink. The customer cheque is given to the MICR device. It reads the information printed on the cheque and sends to the computer for processing.

(ii) OMR
      OMR stands for Optical Marks Recognition. OMR device is used to read handwritten marks or symbols printed on the paper. It uses a light beam to scan the marks and converts them into digital signals. These signals are then input to the computer for further processing.

OMR devices is usually used in education field to check (or mark) the objective type answers of the questions. For example, it is used to check and process the test marks of SAT and GRE (Graduate Record Examination). The pre-printed answer sheet is given to the OMR device. It scans the answer sheet and sends the information to the computer. The computer automatically evaluates and calculates the result according to the program instructions.

(iii) OCR
      OCR stands for Optical Character Recognition. OCR device reads preprinted characters in a particular font and converts them into digital code. The characters printed on paper may be typewritten or handwritten. In case of handwritten, the characters must be of standard size. But in case of typewritten, the characters must have the special type font called an OCR font. The accepted OCR fonts are OCR-A (American standard) and OCR-B (European standard).

The OCR devices are commonly used to precess utility bills and price code printed on the products in departmental stores.

(iv) Magnetic-Strip Card
      A magnetic-strip card has a strip of magnetically encoded information on its back. Usually, the magnetic strip is used in personal identity card. This card is used for personal identification during driving, in the departmental stores, and at public places etc. This magnetic strip card is inserted into a card reader for reading information encoded on the strip.

(v) Smart Card
      Smart card looks like a credit card or ATM card. This card contains a thin microprocessor and memory chip that is embedded in it. The card is inserted into a card reader. The card reader reads information stored on the card. It can also store and update some basic information. A mobile SIM card and an ATM card are examples of smart card.

Audio/Video Devices

Audio input devices
Video input devices
Digital Camera

1- Audio Input Device

Audio input is the process of entering any sounds into the computer. It may include speech, and music etc. The device that is used to enter/record sound (audio input) into computer is called audio input device. Microphone is most commonly used as an audio input device. The main purpose of audio input device is to provide digital input for multimedia computers.

Audio input is in the form of analog signals. It must be converted into digital form before storing it into the computer. For this purpose, there is a special circuit board inside the computer. This circuit board is known as audio board. Audio input device is connected to the audio board. The audio board converts the analog signals of sound into digital form and stores it for further processing. The audio board can also convert digital signals into sound (analog signals).

2- Video Input Device

The process of entering video data into a computer is called video input. Video input consists of motion pictures or movie films. The devices that are used to enter video input into computer are called video input devices. Mostly these devices are used for recording movie films and video images. VCR and video camera are examples of video input devices.

Video input is in the form of analog signals. It must be converted into digital form before storing it into the computer. For this purpose, there is a special circuit board inside the computer. This circuit board is known as video-capture card. Video input device is connected to the video capture card. This card converts the video signals into digital signals that a computer can use.

There are two types of video capture cards.

Frame-Grabber Video Card
Full-Motion Video Card

(i) Frame-Grabber Video Card
     Frame-Grabber Video Card can convert video signals into digital signals only a single frame at a time. A frame represents an image or picture of film at a specific event.

(ii) Full-Motion Video Card
      Full-Motion Video Card is also known as adapter. It can convert video signals into digital signals at the rate of up to 30 frames per seconds. It gives the effect of a continuously flowing motion picture.

3- Digital Camera

A digital camera is an input device. It takes pictures and stores them in digital form. It does not use traditional camera film. It uses a light-sensitive processor chip to capture photographic images in digital form. These images are stored on a small diskette inserted in the camera or on flash memory chip. The stored pictures or photographic images can then be loaded in the computer from the disk (or flash memory chip) for further processing.

Source Data Entry Devices - Categories of Source Data Entry Devices