Barcodes are read with barcode scanners, which use light sensors to detect the patterns of black and white bars in the barcode. The scanner translates these patterns into a digital code that is used to look up information in a database.
Barcodes are read by optical devices.
With a barcode scanner.
data that can read barcodes
data that can read barcodes
http://www.wikihow.com/Read-12-Digit-UPC-Barcodes
1D has vertical bars that are read horizontally, 2D has small squares that are read simultaneously both horizontally and vertically. 2D barcodes can store much more information than 1D barcodes can.
it calculates the checkdigit based on the number read. if the check digit calculated matches with the one read then barcodes has been read correctly.
they did not need one, as the devices to read the barcodes had not been invented yet.
No, the widths of both the black lines and white lines represent a different combination of numbers that the company was assigned and added based on the type of product. See Method 2 for details on how to read barcodes: wikihow(.)com/Read-12-Digit-UPC-Barcodes
Scanners cannot hold too many codes in it. Scanners cannot read barcodes which are torn off or damaged.
there are no barcodes in space only earth has barcodes
Yes, years ago I broke both the UPC and Postal barcode systems with no prior knowledge of their encoding systems and for a while after breaking them could read them visually (however I'm out of practice now and would have to refresh myself on both). The 2D codes are much more difficult to read, but in principle a person could read them too.