Scanners are able to detect the type of symbology being scanned because each symbology has a unique start and stop bar at the beginning and end of the symbol or it has its own unique pattern. Listed below are the most common scanners used.
This scanner is a wand or light pen type scanner. It is the most cost effective type of scanner. These are contact scanners, meaning the tip of the scanner must touch the bar code to read it. Some of the typical problems that are encountered in using this type are scanning to slowly or in a non-continuous or jerky motion, failure to scan the entire symbol, and scanning past the end of the quiet zone.
Laser scanners are available as hand held guns or as mounted units. The laser scans the symbol about 40 time per second, greatly increasing the chances of a correct read. The scanning range is about 4 to 6 inches. The convenience of the laser will usually offset the additional cost of the laser scanner. There are applications where using a contact type scanner is preferred such as scanning a sheet of bar code symbols.
This scanner is priced between a LED scanner and a laser scanner. It is the easiest to train to operate. The scanning range is anywhere from contact to about 3 inches from the symbol. It works on the same concept as taking a picture, cover the bar code with the scanner and press a button. A problem occurs when the bar code is wider than the scan head. This should be determined when the bar code is being produced.