I need to read bar codes but I'm confused about readers.
There seem to be these pen type things that are relatively inexpensive,
or gun scanners that cost a lot more. What are the differences and
what's best for me ?
What type of bar code reader to use for a given application is dependent
upon a number of considerations:
in which reading will take place.
The nature of the
host computer if applicable, e.g. desktop PC or hand held computer,
and whether portable or fixed position.
The required throughput
or volume of reads required.
The quality of the
codes being read and their proximity to other codes.
The level of training/capability
of the likely users.
In 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 bar code reader described below are available in variants
to output the bar code data using any of the main types of output
format: wand (emulation), RS232 or keyboard wedge. Note that the
output format must normally be specified when the reader device
is ordered and the internal reader electronics usually vary between
the different output methods.
outputs the bar code as an analogue
signal which requires decoding prior to being input to the host
computer system. This is the simplest type of interface and relies
on the wand being attached to a device that can do the decoding.
Some "non-wand" scanners can sometimes be configured to
send their output in the same undecoded format - a "wand emulation"
output bar code readers include decoder systems,
outputting the bar code data as an RS232 signal.
output bar code 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
enabling the scanned data to be read in as if typed at the key-board,
so in most cases a USB scanner is functionally similar to a keyboard
wedge interface scanner.
Cordless or wireless
operate in a similar manner
to either the RS232 or keyboard wedge readers but without a cable
connection. They use a short range radio to transmit the scanned
code back to the host. Scanners in this category come in two general
types. First are scanners that have a "send only" radio
that sends the scan to the receiver. The problem with these is that
if, for some reason, the radio signal does not get through (maybe
the user has unknowingly moved out of range of the receiver), then
the user has no way of knowing this and could be sending scans literally
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 cost more than the send-only units, but experience has
shown that it really is worth paying the extra for the certainty
that the data has been successfully transmitted.
There are three general bar code reading types, however there are
even variations of product type within these.