GUIDE
TO BARCODE SCANNER TECHNOLOGY
A barcode is a symbol made up of a series of thick and thin
lines ('bars') with spaces in between. The barcode symbols
are usually printed onto labels or product packaging and depict
a numeric or alpha-numeric sequence. The bar code can be read
by a barcode scanner which scans the graphical lines, decodes
them into individual digits/characters and then transmits
the sequence.
The sequence of numeric or alpha-numeric characters is usually
also printed as text below the graphical lines, and can be
used to manually type the sequence where it cannot be scanned.
In the case of one-dimensional (1D) barcodes, the barcode
is simply a graphical representation of the printed text below
it. The barcode stores no other 'hidden' data other than the
characters that appear in the printed text. Depending on the
type of barcoding symbology used (see below), the barcode
represents information such as a product code, manufacturer
code, country of origin and type of goods.
The interpreted code(s) are then used subsequently by EPoS
and warehouse systems to lookup product information in a database
held on a till or computer, related to pricing, stock levels
and other product information.
Recently, two-dimensional barcodes have been introduced allowing
storage of more information. 2D barcodes store a matrix of
data in a 2-dimensional grid.
What is a Barcode Scanner?
A bar code scanner is a device that optically retrieves the
image of a bar code and converts it to its digital equivalent.
In order for a barcode scanner to obtain a "photograph"
of the barcode, it requires a source of light to illuminate
it. Generally, the source used is a LASER (Light Amplification
by Stimulated Emission of Radiation). A laser is chosen because
it can easily be focused over a long depth of field. Depth
of field refers to the distance throughout which a barcode
scanner is able to read codes. Another instance for the need
of depth of field is when the barcode scanner cannot possibly
contact the code due to protective material, such as glass,
or simply because of the proximity of the item itself.
Bar code scanner technology falls into several categories:-
CCD Barcode Scanners
These scan barcodes from a close distance (around 1-5cm)
and upto the width of the scanner head. For example, a 60mm
CCD barcode scanner will not be able to scan an 80-mm width
barcode. CCD scanners are affordable and suitable for low-volume
usage where good quality barcodes are being scanned.
Laser Barcode Scanners
Laser scanners are more sophisticated than CCD
scanners, being able to scan from longer distances and with
wider scanning widths. They can either be hand-held units
(with or without a counter-top stand) or fixed-mount units
which attach to the wall or flush into the counter.
Barcode Wands or Pens
Bar code pens, also known as light pens, are less frequently
used these days, but are still useful in specialist applications
(such as barcode verification) where their small size gives
them a distinct advantage. They are passed physically over
the barcode to read and decode it.
Linear Image Barcode Scanners
These are the new wave of CCD barcode scanners with the
ability to scan from longer distances and work in a variety
of lighting conditions. They provide laser-scanner like
benefits at a more affordable price.
2D Barcode Scanners
Two-dimensional scanners allow the higher-capacity 2d barcodes
to be scanned and decoded.
Image Scanners
These new wave of technological scanners allow small images
to be captured and transmitted in common graphic file format
(eg. JPG, GIF, BMP etc).
The scanner technology is built into several types of enclosure:-
Hand-held
barcode scanners tend to have a narrow scanner
head, so the barcode will need to placed close and in-line
with the head in order to be scanned. This can slow down
the throughput in busy retail environments. Most hand-held
scanners are provided with (or optionally include) a stand.
Some of these scanners also allow the unit to work as a
presentation scanner when in its stand.
Handheld barcode scanners will either scan on presentation
of a barcode or feature a trigger button.
Fixed-mount
barcode scanners (also known as Presentation
Scanners) have wider read heads, emit laser scan lines at
multiple angles, and so barcodes can be scanned easier and
faster. They are either built into a counter-top stand or
frame which can be adjusted to the required angles, wall-mounted
or they can be flushed into the counter surface.
Mobile Computers / PDA's
are battery-operated portable units with their own processor,
memory, operating system and application software. Supported
operating systems include Windows CE / Windows Mobile /
Pocket PC, Palm OS, Symbian OS and proprietory operating
systems.
For commercial use, mobile computers usually contain integrated
CCD or laser barcode scanner options and may feature a PC
link (usually via a cradle or modem) via RS232 or USB interface
to upload batch data periodically as well as to download
program applications and reference data. Many mobile computers
provide remote connectivity using Bluetooth and other radio
technology as well as wireless Ethernet, GSM and GPRS. Barcode
scanners enclosed in mobile computers are particularly suited
to warehouse and outdoor use.
Industrial Use Barcode Scanners
Our range of barcode scanners includes heavy-duty
products designed for industrial warehouse and mobile use.
They feature rugged, rubberised units to protect against
drops and knocks. Some of the more sophisticated units feature
aggressive laser scanning technology designed to read and
decode damaged or poor quality barcodes.
Scan Trigger
Many barcode scanners can be setup to automatically scan a
barcode on presentation. Others have a trigger, and the barcode
only scans when the trigger is pressed. This is particularly
suitable for items which have multiple barcodes adjacent to
each other - you line up the scanner head with the barcode
first and then press the trigger to scan. This prevents the
wrong barcode from being scanned.
Barcode Symbologies
Most barcodes conform to one of several universal barcode
symbologies. Common barcode symbologies include UPC (UPC-A
and UPC-E), EAN13, EAN8, 2 of 5, Codabar, Code 39 and Code
93. These define the type of characters (letters or digits),
the fixed length of the barcoded data (or variable length
limit), any check digit or other integrity algorithm within
the barcode and the format of the barcode data. RSS is a relatively
new series of symbologies with a more compact format.
With some barcode symbologies, they exist in different versions
or with optional characteristics so the barcode scanner may
need to be configured with the desired settings. Most barcode
scanners readily recognise the common symbologies, but for
less-used barcode symbologies, the scanner may need to be
configured to enable a particular symbology. Some barcode
scanners will be restricted as to which symbologies they support.
You should always check the symbologies of the products/labels
you will be scanning and make sure your intended barcode scanner
supports these symbologies and any required variations. Generally,
retail products use EAN format barcodes.
Code 49 and PDF417 are examples of 2D barcode symbologies.
As many products move towards using this technology, the 2D-compatible
bar code scanners are more future-proof.
The symbology definition controls the character set used
by the barcode symbology. Some symbologies will only permit
the numeric digits 0-9, others will only permit an alpha-numeric
characters (ie. digits 0-9 and alphabetic letters A-Z). Some
symbologies will permit the full ASCII set of 256 characters
(which includes digits, alphabetic characters, punctuation
characters and other special characters).
Generating your own barcodes
If you are generating and printing your own barcode labels
for distribution of products, you should use one of the universal
symbologies and register with the issuing authority who will
assign you a country code, manufacturer code, product category
code and barcode ranges. Many major buyers of products, such
as supermarkets and retail chains, will insist on a particular
barcode symbology being adopted on barcode labels.
The most common format for retail goods is EAN13. This code
is made up of the Number System (or Country code), Manufacturer
Code, Product Code and a check digits. EAN128 is an extended
format which allows additional information such as sizes,
expiry dates and batch numbers to be encoded in the barcode.
If you are in the UK, GS1
is the authority which issues manufacturer codes and publishes
the standards and guideliness for barcode production and formatting.
If you are a UK book publisher, then Nielson
Book Data is the ISBN agency which issues ISBN and Bookland
EAN codes to new publishers and publications and also provides
guidance on the barcode formatting.
If you are a UK magazine or newspaper publisher, the British
Library is the agency which issues ISSN codes.
If you are only using barcodes internally within your organisation,
you do not need to register and can use one of the simpler
barcode symbologies. These can be downloaded free via various
internet sites (although beware of spam sites) or can be purchased
for a small fee.
Barcode Verifiers
Barcode verifiers are specialist devices designed not just
to scan and decode barcodes (like a barcode scanner) but also
conduct a variety of tests on the integrity and readability
of a barcode in accordance with international quality standards.
A barcode verifier is a very useful for product manufacturers
to ensure their barcodes conform to the required international
standards, quality standards and precise customer requirements.
If your customer is a supermarket or major chain store, they
will be very particular about the barcode quality and conformity.
Barcodes can pose a variety of challenges depending on the
size (height and width) of the barcode graphic, the symbology
and coding options used, the quality of the print, the material
it is printed onto, the colour of the material, the environments
it will be exposed to, the environments it will be read/decoded
in and the different barcode scanning equipment that will
be used to scan them. Barcode verifiers allow conformity and
the degree of flexibility for each of the above factors to
be measured and reported.
See our Barcode Verifiers
to quality test barcodes to international standards.
Barcode Labels
Barcode labels are available in a variety of sizes
and formats. They can be printed on label rolls or single
sheets and can either be printed on a normal desk-top printer
or a special barcode label printer for high-volumes. In some
cases, barcodes are not printed onto labels but directly onto
packaging. Label stationery is available for retail packaging,
shelf edge labels, shipping labels and industrial warehouse
use.
See our range of Barcode
Printers for additional information on printing barcodes,
our Barcode Label Software section
for the popular barcode label design software (including support
for all the main barcoding symbologies) and our Labels
section for consumables.
Can't See What you Want?
If you wish to discuss your barcode scanning requirements,
call us for helpful advice. Our website displays our most
popular barcode scanners for retail and warehouse use although
we have a much wider range available as well as replacement
parts and accessories. Please to check for a particular item.
Related Products:-
PDA's / Mobile Computers |
Barcode Printers | Barcode
Label Software | Labels
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