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There
are many different types and complexities of bar
code systems. The type of system required is determined
by the application. A basic bar code scanning system
is fundamentally broken down into a scanner, a decoder,
a computer, and a printer. There are many other configurations,
but this is the fundamental building block for bar
coding. The scanner and decoder together input and
read bar codes into a computer system while the printer
generates bar codes for labeling.
For
the most part, there are three different types of
decoders: wedge decoders, software decoders, and
serial decoders. Wedge decoders are external devices
that wedge between the keyboard and terminal. Software
decoders perform the complete decoding in software
running on a PC. Serial decoders connect into the
communications (COM) port of the PC. Decoded scanners
can either connect via the keyboard wedge or via
the serial port.
There
are two different types of scanners: contact and
non-contact. Contact scanners required physical contact
to scan as opposed to non-contact scanners which
can be several inches to several feet away. Scanners
are discussed in more detail in the Input Device
section. Both types of scanners can be used in the
same system to meet different scanning requirements.
Many
new programs can now generate bar code labels using
common PC printers. Both dot matrix and laser printers
are used to economically generate paper labels using
pin-fed and sheet-fed labels. Thermal transfer and
direct thermal printers produce the highest quality
of print on nearly any kind of face stock. |