ZBar iPhone App
There are many different kinds of barcodes. Each one is called a “symbology”. These are the specific symbologies currently supported by the ZBar app.
These linear symbologies are defined by GS1 specifically for labeling consumer products.
UPC-A is actually just another name for an EAN-13 barcode that starts with a leading zero (the country code for the US). If the zero is dropped, the resulting 12-digit product number is known as a GTIN-12.
EAN-8 is a shortened version of EAN-13 that only encodes 8 digits and uses specially allocated GTIN-8 product numbers.
These symbologies use simple bars to encode data in just one dimension. Note that, in many cases, it is impossible to know the intended use for these barcodes just by looking at the decoded data - it may be a package tracking number, a library book, a receipt or transaction number, just about anything!
Code 128, defined by ISO/IEC 15417, is a very dense, secure and flexible symbology that can encode any ASCII character. GS1-128 is a special variation of Code 128 that can be used for structured product data.
Code 93, defined by AIM-BC5, is less dense but somewhat more secure than Code 128. It is used by the health care industry and some postal systems.
Code 39, defined by ISO/IEC 16388, is still very popular despite inferior density and data security. This symbology can represent only numbers, capital letters and a few punctuation marks. It is used by the DoD, in the health care industry, for some tracking numbers and document automation systems, among others.
Interleaved 2 of 5, defined by ISO/IEC 16390, is an older symbology that can represent only numbers. It is still frequently used in various applications, even though other symbologies are usually a better choice.
GS1 DataBar, defined by ISO/IEC 24724, is also used to label consumer products. It is frequently found on produce and coupons. Formerly known as Reduced Space Symbology (RSS), this symbology offers very high density and data security. The base symbol encodes only a GTIN-14 product code, similar to EAN/UPC, while the “expanded” variant supports application identifiers (AIs) with additional product data.
These symbologies encode data in two dimensions - horizontally and vertically - allowing for much higher capacity. They also offer Error Checking and Correction (ECC) for very high data security; most symbols may be read even if sections are missing or damaged!