Automatic Identification and Data Capture Techniques - an
The technologies used in the world of
Automatic Identification and Data Capture (AIDC) are varied and
often used in combinations to provide a broader base of
information flow. This article attempts to summarize the
technologies in common use today, and give the reader a basic
understanding of the technology and its uses and limitations.
Barcode: Perhaps the oldest of the AIDC technologies, barcode
can be looked upon as the best known and probably most
successful to date of the technologies. We are all familiar with
the basic barcode on our box of cereal, or the jar of honey that
we buy in the supermarket. This barcode is called UPC/EAN and is
but one variation of over 250 barcodes that have been designed
over time. Barcodes like this are referred to as linear barcodes
as they are made up off a collection of bars and spaces side by
side. Fortunately many of these barcodes have never gained broad
acceptance and we usually only consider 10-12 linear barcodes.
The most common examples in use today are: UPC/EAN, Code 128,
Code 39, Code 93, and Interleaved 2 of 5. Typical data content
capacity varies from 8 to 30 characters with some barcodes
restricted to numerals only, and others using full alpha-numeric
information. Standards for these barcodes are published by AIM
and are currently in progress at ISO.
Linear barcodes are used in many applications where the use of a
simple numeric or alpha-numeric code can provide the key to a
database of "products". The most obvious limitation is the
amount of data that can be stored in a linear barcode, though
other problems can exist with the substrate that the barcode is
printed on providing insufficient contrast or poor ink
receptivity which can cause the quality of the barcode to be
less than ideal.
2D barcodes: A new growth area in the world of barcode is the
two-dimensional versions. Several variations of 2D are available
and as these do not all comprise bars and spaces the more
accurate name of 2D symbologies is used. 2D symbologies provide
a means of storing large amounts of
data in a very small space.
Whether you consider stacked symbologies (linear barcodes
stacked on top of each other), matrix symbologies (comprising a
matrix of light and dark elements, circles, squares, or
hexagons), or packet symbologies (a collection of linear symbols
"randomly" arranged on a page). Examples of the three types
include PDF417, Code 49 Code 16K (stacked), Code One, MaxiCode,
Data Matrix, Aztec Code, QR Code (matrix), and Super Code
(packet). Standards for each of these symbologies are either
available from AIM or are in progress. Several of these
standards have also been submitted to ISO for standardization.
2D symbologies have a major advantage over linear barcodes, they
can store vast amounts of data. Individual symbols can store as
much as 7000 numeric only or 4200 alpha-numeric characters. Many
of the symbologies also have the ability to use a device called
structured append that allows messages to be split over multiple
symbols, providing almost infinite storage space. The
disadvantage of the 2D symbologies is that a special scanner is
needed. Matrix symbologies need a vision based scanner to read
the data, though some of the stacked symbologies can be read
with a rastering laser scanner. Expect to see many new scanners
with variations in technology in the next year or so.
Card Technologies - Magnetic Stripe: The first magnetic stripe
cards were used in the early 1960s on transit tickets and in the
1970s for bank cards. Since then the use of magnetic stripes
continues to grow. Credit cards were first issued in 1951, but
it wasn’t until the establishment of standards in 1970 that the
magnetic stripe became a factor in the use of the cards. Whether
the card is a credit card sized plastic card, a thin paper
ticket or an airline boarding card, the uses for magnetic stripe
technology have grown considerably. Today with an
infra-structure that encompasses every store in the high street
giving them an ability to read the information on the magnetic
stripe, the technology is everywhere. Although some limitations
exist in the amount of information that can be stored on the
stripe and the security of the data, solutions to solve these
problems exist from various vendors.
With the advent of new technologies many people have predicted
the demise of the magnetic stripe. However, with the investment
in the current infrastructure this is not likely to be any time
soon. Magnetic stripe technology provides the ideal solution to
many aspects of our life. It is very inexpensive and readily
adaptable to many functions. The standardization of high
coercivity for the financial markets has provided the industry
with a new lease on life. This coupled with the advent of the
security techniques now available means that many applications
can expect to be using magnetic stripe technology for the next
ten to twenty years. Standards for magnetic stripe technologies
are available from ISO, where the focus is on the interchange
environment, other standards are available from AIM. More
Card Technologies - Smart Card: Smart cards are not new, the
first patent was filed in France in 1974 and the first cards
were used in France in 1982. The technology was rapidly accepted
in Europe because the high cost of telecommunications made
on-line verification of transactions very expensive. The smart
card provided the mechanism to move that verification off line,
reducing the cost without sacrificing any of the security. Smart
cards are credit card-sized plastic cards that contain
relatively large amounts of information in an imbedded
micro-chip. There are several terms used to identify cards with
integrated circuits embedded in them. The terms "chip card,"
"integrated circuit card", and "smart card" really all refer to
the same thing.
There are two types of smart card. The first is really a "dumb"
card in that it only contains memory. These cards are used to
store information. Examples of this might include stored value
cards where the memory stores a dollar value which the user can
spend in a variety of transactions. Examples might be pay phone,
retail, or vending machines. The second type of card is a true
"smart" card where a microprocessor is embedded in the card
along with memory. Now the card actually has the ability to make
decisions about the data stored on the card. The card is not
dependent on the unit to which it is attached to make the
application work. A smart purse or multi-use card is possible
with this technology.
As there is a microprocessor on the card, various methods can be
used to prevent access to the information on the card to provide
a secure environment. This security has been touted as the main
reason that smart cards will replace other card technologies.The
microprocessor type smart card comes in two flavors - the
contact version and the contactless version. Both types of
card have the microprocessor embedded in the card however
the contactless version does not have the gold plated
contacts visible on the card. The contactless card uses a
technology to pass data between the card and the reader
without any physical contact being made. The advantage to
this contactless system is there are no contacts to wear
out, no chance of an electric shock coming through the
contacts and destroying the integrated circuit, and the
knowledge that the components are completely embedded in the
plastic with no external connections. The disadvantage to
this is that the card and reader are more sophisticated and
hence are more expensive. The biggest disadvantage today
with smart cards is the cost to create a smart card system.
Individual card prices have fallen over the past few years
but they are still high when compared with a magnetic stripe
card. The biggest advantage is of course the amount of data
that can be stored and the security that can be built into
the card. Standards for the smart card technologies exist
from ISO for both contact and contactless versions of the
Card Technologies - Optical Card: Optical memory cards use a
technology similar to the one used for music CDs or CD ROMs.
A panel of the "gold colored" laser sensitive material is
laminated in the card and is used to store the information.
The material is comprised of several layers that react when
a laser light is directed at them. The laser burns a tiny
hole (2.25 microns in diameter) in the material which can
then be sensed by a low power laser during the read cycle.
The presence or absence of the burn spot indicates a "one"
or a "zero". Because the material is actually burned during
the write cycle, the media is a write once read many (WORM)
media and the data is non volatile (not lost when power is
removed). The optical card can currently store between 4 and
6.6 MB of data which gives the ability to store graphical
images such as photographs, logos, fingerprints, x-rays,
etc.. Standards for optical cards can be obtained from ISO.
The major disadvantage with the optical card is the fact
that it is a write once technology and so the amount of data
storage available is used up with every piece of new data
written. In some applications this can be considered an
advantage because it maintains the complete history of
changes made to the card.
Radio Frequency Identification (RFID): The hot technology in
the AIDC arena is RFID. Although it has been available for a
long time, it has only been available in proprietary formats
from a variety of vendors. Work is at last progressing to
provide standardized forms of RFID, with standardization
work being done at ISO and AIM.
RFID provides a means of obtaining
information on an item without making direct contact.
Reading and writing distances can vary from a few
millimetres to several metres depending on the technology
variation used. The tags themselves come in a variety of
form factors from credit card sized plastic cards, to tiny
injectable glass transponders for tracking animals, to large
"bricks" suitable for use on the side of containers on
trains. The actual technology used to implement RFID varies
depending on manufacturer and application, with frequencies
used varying from 125kHz to 5.8GHz. There are many obstacles
in the path of creating standards for RFID including the use
of globally available frequencies. The work to remove some
of these obstacles has started and the chance for global
standards is now very real. Whether you are looking for a
one-bit electronic article surveillance device or a
multi-character inventory label, RFID has a solution that
can provide a non-contact method for storing the
The biggest advantage is the non-contact aspect of the
technology, with read distances to tens of metres available.
This can also be a disadvantage where the reading of
multiple tags can take place simultaneously can occur and
special steps have to be implemented to assist with this.
Biometrics: Not truly an AIDC technique, however the use of
biometrics in conjunction with AIDC techniques is becoming
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