Barcode reader

A barcode reader (or barcode scanner) is a computer peripheral for reading barcodes printed on various surfaces. Like a flatbed scanner, it generally consists of a light source, a lens and a photo conductor translating optical impulses into electrical ones. Additionally, nearly all barcode readers currently produced contain decoder circuitry analyzing the barcode's image data provided by the photo conductor and sending the barcode's content to the scanner's output port.

Many different types of barcode scanners are available. They can be distinguished as follows:

• By light source:

  LED scanners 

  also referred to as CCD scanners -- even though the CCD is in fact the photo imaging sensor, not the light source

  laser scanners 

  much more expensive than LED scanners but are generally capable of longer maximum scanning distances

• By housing:

  handheld scanner 

  with a handle and typically a trigger button for switching on the light source

  pen scanners (or wand scanners) 

  a pen-shaped scanner that is swiped across a barcode

  stationary scanners 

  wall- or table-mounted scanners that the barcode is passed under or beside. These are commonly found at the checkout counters of supermarkets and other retailers.

Most barcode readers use a PS/2 wedge cable for output: This cable is connected to the host computer's PS/2 keyboard port with its first end, to the keyboard with its second, and to the barcode reader with its third end. The barcode characters are then received by the host computer as if they came from its keyboard. Many readers can be also equipped with an RS-232 output port so that the decoded characters arrive at the computer via one of its RS-232 connectors. USB is supported by many newer scanners, in many cases a choice of USB interface types (HID, CDC) are provided.

Today's barcode scanners handle all popular barcode symbologies like EAN/UPC, Code 39 or Code 128. A special type of barcode reader is the area imager reader or 2D reader that typically uses LED illumination and a CCD or CMOS imager that operates much like a digital camera. These are necessary for decoding two-dimensional matrix codes such as Datamatrix, QR Code, Aztec Code and MaxiCode in addition to linear and stacked symbologies.

See also

• Barcode

External links

• Barcode reader manufacturers
  • Metrologic Instruments
  • Symbol Technologies
  • Intermec
  • Handheld Products
  • DataLogic