Barcode Scanner Selection Criteria

A typical request is help in selecting a barcode scanner.  Here are some basic considerations for making the choice.

• Linear (1D) or 2D barcodes
• Code density-The size of the minimum bar width or element in the code
• Tethered or Cordless
• Distance from the scanner to the barcode
• Environment-Ruggedness Requirement
• Method of printing the codes

Some thoughts.

Linear codes can be read using Laser or Linear Imager scanners. These are single line raster scanners. They are available as hi-density, standard range and extended range versions to handle the range of code sizes and reading distances. The most economical are tethered by a cable to a workstation and require no special software or drivers as they emulate a keyboard. Multiple cable interfaces are available including USB, RS232 and PS/2.

Cordless versions behave the same way as the cable is replaced by a short distance radio, most typically a Bluetooth link good to about 10 meters although longer range radio versions are available. Some applications require scanners with aiming capability when there are multiple barcodes on a label or reading at long range, out to 40 feet. Others survive hostile environments and long drops to concrete.

Special scanners are available that can read poor contrast etched or dot peened codes

2D barcodes are matrix codes such as Datamatrix, QR, and Aztec or stacked linear codes such as PDF417 used on driver’s licenses. Readers for these codes utilize image capture technology. The scanner/reader takes a picture, captures the image and algorithmically processes the image to extract the data in the code.  The reading is inherently omnidirectional so the user need not orient the scanner with respect to the code  which is not the case with a laser or linear imager scanner.

Many of these scanner are excellent in reading codes from PDA and  cellphone screens which are highly reflective. As with linear only scanners there are versions for various densities and ranges. These Imager readers also read linear barcodes. It is always a good idea to provide sample codes for evaluation to ensure a good selection, please send us your codes for evaluation.

2D Barcodes are symbologies that are capable of storing more information than can normally be contained in a conventional linear barcode.

These include:

	AZTEC – Excellent for viewing on cell phones and PDA displays:
	QR Code – Marketing & Transportation applications:
	DATAMATRIX – a square symbology, of varying densities used extensively in part marking and document ID as a large number of characters can fit in a small space:
	PDF417 – can be printed at a variety of aspect ratios and densities. Used in transportation, manifests, and personal ID including state driver’s licenses.

2D Barcodes can serve as portable data files, enabling the user to access information such as lot processing, shipment manifest, and serial number/sku data remote from the network database.

Most 2d codes require an imager, which algorithmically processes the image. Imager scanners are effectively digital cameras with integrated processors and therefore can also capture images such as signatures. As with linear barcode scanners, they can interface as a keyboard or serial emulation device, via USB, PS/2 or serial connection