Identification and Control Equipment (I) - Bar Code

Series of vertical bars and spaces representing numbers and other symbols; it is affixed to postal mail, retail store items and identification cards in order to identify a particular location, person or product number. The symbol usually consists of five parts: a quiet zone, a start character, data characters which include an optional check character, a stop character, and another quiet zone. Although there is no particular standard bar code, there are several different bar code standards (symbologies) serving different industries, geographic needs or uses. The most common bar code standards are; Code 39 (Code 3 of 9), serving in Identification, inventory, and tracking shipments; Interleaved 2 of 5, serving the shipping and warehouse industries; and Uniform Product Code (UPC) serving the Retail stores in sales checkout, inventory and such.

History traces back to its first patent for a bar code type product (US Patent #2,612,994), which was issued to inventors Joseph Woodland and Bernard Silver on October 7, 1952. This bar code was made up of a series of concentric circles described as a "bull's eye" symbol, and over time, has converted into today’s UPC bar code.

Bar code consists of information, called barcode data, or also point-of-sale (POS) data. It is automatically gathered as a consumer's purchases and place through a check-out. Massive volumes of such data is gathered every day by the POS terminals and processed before being very useful for marketing purposes, such as planning on pricing a particular product, or initiation of sales campaigns.

Barcode Reader

Bar code is read by a barcode reader, which is a stationary or hand-held input gadget used in capturing and reading information contained in it. Also called a price scanner or POS scanner, a barcode reader uses a laser beam sensitive to the reflections from the line and space thickness and variation before translating the reflected light into digital data transferred to a computer for immediate action or storage. A barcode reader consists of a scanner, a built-in or external decoder and a cable which is used to connect the reader with a computer.

Consisting of five basic types, the simplest barcode reader is the pen wand, which contains no moving parts. It is known for its durability and low cost. On the other hand, it can be challenging to the user, as it has to stay in direct contact with the bar code, held at a certain angle, and moved over the bar code at a certain speed.

Another type is the slot scanner which remains stationary when the item with the bar code on it is pulled by hand through the slot. It is normally used to scan bar codes on identification cards.

Also, there is the type of bar code reader, the CCD scanner, having a better read-range than the pen wand and is often used in retail stores. Normally, a CCD scanner has a "pistol" type interface and has to be held at most 2.5cm from the bar code. Although several readings are taken to reduce the possibility of errors every time the bar code is scanned, it cannot translate a bar code that is wider than its input face.

Furthermore, there is another type called the camera reader, or image scanner. It uses a small video camera capturing an image of the bar code before using sophisticated digital image processing techniques to translate the bar code. The camera reader can read a bar code from about 7.5cm to 23cm away and commonly costs less than a laser scanner.

Lastly, a laser scanner, either stationary or hand-held, does not have to be close to the bar code to do translate it. Regardless of orientation, it uses a system of mirrors and lenses allowing the scanner to translate the bar code, and can easily translate a bar code up to 61cm away. A laser scanning may perform up to 500 scans per second to reduce the possibility of errors. A specialized long-range laser scanner is capable of reading a bar code up to 0.9m away.