Reading Technologies
Choosing the right barcode reader means weighing the reading environment, host computer type, required throughput, code quality, and user skill level, alongside the reader's interface and physical reading technology.
I need to read barcodes but I'm confused about readers. There seem to be pen-type devices that are relatively inexpensive, and gun scanners that cost a lot more. What are the differences, and what's best for me?
The type of barcode reader to use for a given application depends on a number of considerations:
- The environment in which reading will take place.
- The nature of the host computer, if applicable -- e.g., desktop PC or handheld computer -- and whether it is portable or fixed in position.
- The required throughput, or volume of reads needed.
- The quality of the codes being read and their proximity to other codes.
- The level of training and capability of the likely users.
When selecting a scanner, you will usually need to consider two main features: the nature of the interface to the host device, and the physical reading technology used.
Most types of barcode reader described below are available in variants that output barcode data using one of the main output formats: wand (emulation), RS232, or keyboard wedge. Note that the output format must normally be specified when the reader is ordered, and the internal reader electronics usually vary between the different output methods.
Wand (Emulation) outputs the barcode as an analogue signal that requires decoding before being input into the host computer system. This is the simplest type of interface and relies on the wand being attached to a device that can perform the decoding. Some "non-wand" scanners can sometimes be configured to send their output in the same undecoded format -- a "wand emulation" mode.
RS232 output barcode readers include decoder systems, outputting the barcode data as an RS232 signal.
Keyboard wedge output barcode readers include a decoder and connect between the keyboard and the host PC. The coded data is sent to the host as key presses (the keyboard continues to operate normally).
USB (Universal Serial Bus) is an increasingly popular way to connect a scanner to more modern PCs equipped with USB ports. USB interface scanners are usually supplied with driver software that lets the scanned data be read in as if typed on the keyboard, so in most cases a USB scanner is functionally similar to a keyboard wedge interface scanner.
Cordless or wireless readers operate in a manner similar to RS232 or keyboard wedge readers, but without a cable connection. They use short-range radio to transmit the scanned code back to the host. Scanners in this category come in two general types. The first are scanners with a "send only" radio that transmits the scan to the receiver. The problem with these is that if, for some reason, the radio signal does not get through (perhaps the user has unknowingly moved out of range of the receiver), the user has no way of knowing this and could be sending scans into thin air. The second, better-quality category of wireless scanners can also receive a validation signal from the base station, so the scanner will not "beep" unless the scanned data has actually been received by the base station. This second category of devices obviously costs more than send-only units, but experience has shown that it is worth paying extra for the certainty that the data has been successfully transmitted.
There are three general barcode reading types, though there are further variations of product type within each.
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