Choosing the Best Bar Code Symbology

The type of bar code used is a major factor in the performance of the entire m-ticketing system. There are several symbologies you can choose from. Each has important attributes that need to be considered before being employed in an m-ticketing application. Note that each bar code shown below contains the same amount of data and is shown in true size.

Linear Bar Codes

Linear bar codes are not ideal for m-ticketing applications for several reasons. First, linear bar codes quickly grow large as you add data - considering the typically small display size of a mobile device, this severely limits the amount of information that can be included in the code. In addition, the start and stop areas of the bar code that indicate where the information is contained are located on the outer edges, leading to scanning problems since electronic displays are generally dimmer at the edges. Finally, the error correction of linear codes is far less than that of 2D codes, leading to greater potential for misreads or unreadable data.

PDF417

Portable Data File 417 (PDF417) is a stacked linear bar code with built-in redundancy and error correction. The start and stop areas of this bar code are on the outer edges, as are the necessary white spaces surrounding the boundaries of the bar code - this can lead to potential problems when reading from digital displays because these are generally dimmer at the edges. In addition, the way PDF417 is built up makes it very dif. cult to display correctly on an electronic display.

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