BAR
CODE
The
bar code is a technology that has
transformed the way of doing business.
From its creation, it has eased all the
tedious activities of administration such
as inventory control, tally of sold
articles and has improved the agility in
customer service. Having reliable
information, gathered at the point of
capture, managers can take better and
timely decisions about their businesses.
for example, what products must be bought,
which ones are obsolete, and which need to
be auctioned.
A
bar code has become an everyday
indispensable tool. Some can remember when
going groceries-shopping to a supermarket,
you could have spent close to an hour just
to pay for the items; today there are
hardly three people in line. Thanks to
bar-code technology it is possible to
track a package along its path - form the
collection point, going through different
transport stages, and final delivery.
Possibly you have noticed that many
companies keep their time and attendance
records through ID cards with bar codes.
It is so useful that is "invisible" in our
daily activities. It is hard to think how
we would live without it.
The
greatest benefits of this technology are
the ease of use, the data-capture speed,
the reliability of the data, the use of
established standards and its low cost. It
is impossible to mention all the benefits
on this technology in such a short space,
there fore we just present a brief
summary.
1932
- Wallace Flint. makes the first proposal
to automate a retail establishment.
1949 - Joe Woodland Berny Silver.
Propose the first Patent for bar codes (US
patent 2,612,994). "Bull's eye code"
1959 - Girard Feissel - Proposes a
numeric code made of bars.
1960 - First use in railroad
cars.
1967 - Kroger Store make a pilot
test in Cincinnati, OH. RCA develops the
scanner.
1970 - US Committee on Retail
Industry establish a panel to select a bar
code standard.
1971 - Use of Plessey code in
European Libraries.
1973 - UPC code is approved for
products sold in retail. Based form an IBM
proposal.
1974 - David C. Allis de Intermec
develops code 39 alphanumeric.
1978 - Red cross approves the use
of bar codes for blood banks.
1979 - EAN symbol is adopted.
1982 - US Defense department
publishes LOGMARS 1189
1984 - AIAG publishes their
standards for Automotive industry.
1988 - HIBCC publishes their
standard for Health industry.
1988 - VICS Voluntary Industry
standard is published.
1999 - ANSI standard for generic
shipping labels with EDI applications.
Uses Code UCC/EAN 128.
BAR
CODE DESCRIPTION
- A
Bar code is an array of black bars in a
white background in different widths,
seen from the readers perspective.
- The
combination of bars and spaces describe
a pattern that represent information.
- It
is graphical representation of
information (numbers or text) that
computers can read.
- They
are easily read by bar code scanners
(laser, CCD, Omnidirectional,
wands).
- They
are bidirectional. It does not matter
the direction in which the code is
read, the same information will be
read.
- The
amount of data is a function of the
code used.
- UPCA
- 12 numeric characters.
- EAN13
- 13 numeric characters.
- EAN8
- 8 numeric characters.
- Code39
- variable length
alphanumeric.
- Typically
narrow bars are 10 mils and wide bars
are 30 mils.; both being black and
white. High density bar codes have bars
of narrower widths and Low density
codes have wider bars.
- They
have delimiters characteristic of every
code type.
- It
is necessary to have a quiet zone
between the code and the package
elements. This area lets the scanners
know where the code begins and
ends.
- Check
digits - Some bar codes have internal
validation information, that verifies
if the information read is consistent.
A bar code will not be transmitted if
after reading a bar code and performing
an internal algorithm the verifying
digit does not match the one
read.
- The
type of bar code used many time will be
determined by the application in which
it will be used. If it is retail it
will be UPC/EAN / If it is industry it
will be C39/C128.
Because
of the following benefits, we believe the
use of bar codes will be a viable
technology for many years to
come.
- Low
Cost - It is printed at the same time
as the packaging material, therefore
the cost is almost null.
- Speed
- A 14-digit bar code can be read in
less than a second, while typing the
information manually could take 5
seconds.
- Reliability
- Manual data capture has on average
one error every 300 characters typed, a
bar code can reduce this number to one
error for every million characters.
- Ease
of Use - Training for new employees in
bar code technology is trivial - aim
and shoot.
- Use
of commercial and industrial standards.
Well documented and
accepted.
- Economical
equipment - Today bar code scanners and
printers are the most cost effective in
the market, comparing them to other
alternatives like OCR (optical
character recognition), Magnetic
stripe, Radio frequency (RFID tags) and
voice recognition.
BAR
CODE SYMBOLOGY
There
are many symbologies to choose from in the
same way there are languages. These codes
have been designed to meet the
requirements of come application. Many of
them have become useless because industry
or commercial has favored another in their
use.
Among
the most important we can find the
following:
UPC/EAN
- (Universal Product Code/ European
Article Number)
- Numeric
code with 8,12 o 13
characters.
- Standard
used in general merchandise in
Retail.
- Has
2 numeric sections and 3
delimiters.
- Uses
three encoding schemes
(A,B,C)
- Using
7 modules, each digit is formed with 2
black bars and 2 white bars of
different widths (1 to 4).
- Structure:
Contains information about the country,
manufacturer and product and one
verifying digit. For
example
- 7501234512343
750 - Country (Mexico) assigned by EAN
international.
12345 - Manufacturer number assigned by
AMECE.
1234 - Product number assigned by
manufacturer.
3 - Verifying digit calculated by an
algorithm.
(Note: Because this scheme changes form
country and application, please contact
your local supplier of bar codes to
obtain the correct
structure).
INTERLEAVED
2 OF 5 (ITF).
- Numeric
code with variable length.
- Used
in Dispatch units (DUN14) or internal
company information.
- Has
2 delimiters, one at the beginning and
at end of the code.
- The
number of digits must be even, codified
data is arranged in pairs. Inside the
pair, the first digit is coded in black
bars and the second digit in white
bars, interleaved one inside the
other.
- Each
digit is coded with 5 bars, two of them
being wide (3:1)
- In
general this code does not contain
verifying digit.
- Structure:
Only in DUN14 (Dispatch unit number)
the structure is well defined having
the same as UPC/EAN with one or two
digits in front that identifies the
unit size and one verifying
digit.
- To
avoid misreads it needs two wide bars
at the top and bottom of the
code.
CODE
39 (C39).
- Alphanumeric
code with variable length.
- Standard
used by industry to identify materials,
serial numbers and complementary
information.
- Has
two delimiters at the beginning and end
of code with the symbol "*"
(asterisk).
- Each
digit is made out of 9 bars (5 black
and 4 white), 3 of them being wide (in
general 2 of them black and one
white).
- Without
verifying digit.
- Can
only code 44 character (0-9,
A-Z,-,Space,*,$,/,+,%)
CODE
128
- Alphanumeric
code with variable information.
- Introduced
in 1981 and gaining popularity since
1990.
- From
its high density, verifying digit, and
general encoding it is becoming an
important standard.
- Standard
used in industry for the identification
of materials, serial numbers, and
complementary information.
- With
three coding schemes A,B and C (numeric
with double density). Each scheme can
codify 106 characters. this means that
each graphical representation may have
different meaning depending on the
scheme used.
- Has
two delimiters, at the beginning and at
the end. It is possible to change the
coding scheme inside the
code.
- Each
digit is made of 11 modules with 3
black bars and 3 white bars of
different widths.
- Contains
a verifying digit.
- Can
represent the 128 ASCII
characters.
- Used
in the UCC/EAN128 standard.
PDF417
- Bi-dimensional code.
- Introduced
in 1990 by Symbol
Technologies.
- Does
not use separating bars which provides
great efficiency
- Contains
error correcting
characters.
- The
code may hold 1000
characters.
Data
Matrix - Bi-dimensional
code.
- Introduced
by Symbol Technologies.
- Symbology
similar to a chessboard.
- Contains
two white sides and two dark
sides.
OTHER
SYMBOLOGY - low use.
There
are other symbologies that their use
has been limited, among them we can
find:
- Code
93 - 1982 - high density variant of
C39.
- Codabar
- 1972 - libraries, blood banks, air
delivery.
- Code
11 - 1977 - Telecom
equipment.
- Plessey
- 1971 -
- Matrix
2 of 5 - variation of Code 11 - Nieaf
company.
- Nixdorf
Code - 1970 - Nixdorf Computer
company.
- Delta
Distance A - 1971 - IBM
- AMES
Code - 1974 - Medical records - AMES
company.
- Meter
Code - 1992 - Number wheel meters -
Sprague Ackley of Intermec.
- Bone
Code - 1992 - Fish
breeders.
- POSTNET
- Very well used by the US postal
service.
- StateCode
- variant of POSTNET to be
alphanumeric.
Bi-dimensional
codes - low use.
- Code
49 - 1987 - Identification of small
parts - Intermec.
- Codablock
- Identcode Systeme.
- Code
16K - similar to Code 49.
- USD-5
- "Sludge code"
- Vericode
-
- Maxicode
- Hexagonal code used widely by
UPS.
- ArrayTag
-
- DotCode
-
- LEBcode
-
- QR
Code - 1994 - Japan.
The
first step in making a bar code system is
to have printed symbols. Today most
manufacturers already include bar codes in
their products. Therefore the
implementation is easy. Nevertheless if
you are a manufacturer and require to
print some bar codes, you will need a
thermal
transfer label
printer.
To
read a symbol, bar code scanners are
required. There are three main
technologies available - Laser
scanners,
CCD
Scanners,
Omnidirectional
scanners
or hands free. Wand scanners are obsolete
(we do not recommend their
use).
In
addition we require a device that will
make a record of the codes read. There are
computers and portable data terminals. A
software is required with an application
you find suitable / i.e. inventory
control, point of sale, work in progress,
access control, fixed asset control, among
others.
Once
the equipment is connected together and
the personnel trained, just aim at the
code and when a "Beep" is heard the data
will be read in your computer; that
simple. What you do with that information
is another story that does not have to do
with bar codes.
Your
computer will perform the activities
needed for the required end. If you use a
point of sale software, then the software
will register the sale, will look up the
price in its data base, will deduct the
product form inventory and will print the
sales receipt. It will send a signal to
the printer to open the cash
drawer
and will register the method of payment,
being cash or credit card or customer
credit account.
From
it ease of use, the advantages we can
mention are:
- Information
goes directly form the scanner to the
computer.
- Human
intervention is minimal.
- Errors
are reduced to one in a million
characters read.
- Information
is in real time, just when events are
taking place.
All
the advantages and benefits mentioned have
promoted the wide diffusion of bar code
technology. today it is possible to find
it in many applications as
follows:
- Access
control.
- Asset
management.
- Warehouse
management.
- Point
of Sale
- Work
in Progress.
- Libraries
- MRP
and MRP II.
- Warehouse
receiving.
- Material
Shipping.
- In-route
sales.
- Electronic
Data interchange (EDI).
- Hospitals
and Health.
- Package
and Messenger tracking.
- Luggage
tracking (airlines).
- Postal
service and Messenger
services.
- Supermarkets.
- Just
in time (JIT).
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