wilamowski-b-m-irwin-j-d-industrial-communication-systems-2011

8-4 Industrial Communication Systems
To facilitate a common platform for national trade in the United States, the Universal Product Code
(UPC) was adopted in 1973 [9]. On the other side of the Atlantic Ocean, the UPC code was augmented
to form the European Article Numbering Scheme (EAN-13). It was accepted by most European nations
as a common standard in 1974. By adding an extra code to the European scheme, an international
standard (EAN-14) was born.
8.3 Magnetic Stripes
Besides coding a product, a bar code is applicable in marking a pack of fresh produce and identifying a
person. Strictly speaking, a bar code cannot be treated as an identity because a code is usually assigned
to a line of products, not an individual item. In the existing format, it has no information on its owner,
not to mention when and where the product was made. Should bar code be used to specify trillions of
items sold annually all over the world uniquely, it must be substantially elongated. Consequently, at
least one side of the box must be reserved for accommodating its code of more than a hundred digits. In
fact, a bar code is hardly adequate to code 6.7 billion men and women on earth. However, for a simple
stand-alone case, it is feasible to assign every person in a specific group an exclusive bar code, such as
the boarding pass for a given air flight.
However, with industrialization and urbanization come the inevitable socioeconomic changes, structurally
and nonstructurally. Similar to New York, Tokyo, Sao Paulo, Mumbai, Lagos, Mexico City, and
Shanghai, more and more metropolitan areas of 20 million residents are emerging fast in the Eastern
and the Western worlds, in both the Northern and the Southern hemispheres. For an effective population
control and better town planning, a simple yet efficient scheme for authenticating personal identities
is needed to screen out illegal immigrants.
It is understood that personal records are kept in the government archive in both the written and
electronic formats. The issue on hand is to duplicate an abridged version and store it on a portable
device, inexpensively. In line with the government practice of recording the data semipermanently in
decks of magnetic tapes, a short strip of magnetic tape is cut and pasted on a name-card sized paper
or polymer card. This is called the magnetic stripe card because multiple tracks of record are found in
a strip. From the bar code to the magnetic stripe, the trade-off is physical contact due to swiping the
magnetic tape over a ferromagnetic head as wear off is inevitable.
Unlike data shown in a bar code, the magnetically stored data could be rewritten easily. Fortunately,
a magnetic stripe has adequate room for encrypting the sensible data. With data encryption and other
security measures, the magnetic stripe card is now used extensively as a prepaid calling card or a debit
card. It is also used in access control, such as a ticket to a specified movie at a given time or a bus ride at
a given time (Figure 8.4).
(a)
FIGURE 8.4
(a) A cable car ticket and (b) magnetic stripe card in Hong Kong.
(b)
© 2011 by Taylor and Francis Group, LLC