The success of the
Universal Product Code System depends upon being able to easily identify
individual products at a retailer front-end by rapidly moving these
products past a symbol reading scanner. To insure maximum productivity,
the system was designed to require a minimum effort in presenting and
reading the UPC symbol with the scanner. Omnidirectional symbol scanning
is basic to the system's success.
The UPC symbol
geometry as described in the Symbol Specification manual facilitates
omnidirectional scanning. Any truncation or shortening of the bar height
from that specified in the manual leads to a degradation of this
scanning ability. Truncation might consist of decreasing the specified
bar height by a fraction of an inch or, in other cases, by decreasing
bar height to the point where the overall height of the symbol becomes
only a fraction of an inch. The more a symbol is truncated or shortened
the more precisely it must be presented to the scanner for reading and
the poorer the productivity becomes.
No truncation is
permitted by the UPC Symbol Specification. It is recognized, however,
that in some cases the package size and/or shape make it impossible to
contain a "full height" UPC symbol. Since symbol height is directly
related to productivity at the retail front-end, the process of
truncation should be used only to the degree necessary and only as a
last resort where no symbol at all would be the only other alternative.
Truncation should never be used on packages large enough to accommodate
a full size symbol.
It might also be
interesting to note that a truncated symbol is somewhat more tolerable
on small packages than on larger ones primarily because of the small
package size. A truncated symbol requires precise orientation to a
scanner. The shape of a small package, for instance individual packs of
chewing gum, will assist a checker in properly orienting the packages to
a scanner window. A larger package would lead the checker to expect a
full height, or omnidirectional reading symbol and, in addition, would
provide little visual guidance for orienting the product to read a
truncation should be avoided except as a last resort. Truncation will
never be permitted by specification because of its adverse effect on
front-end productivity. If truncation is absolutely necessary, it should
be held to an absolute minimum since the more the truncation the greater
will be the adverse effect on productivity.