User manual

Glossary–2
Buffer– refers to a storage facility in a data communications system which can
compensate for a difference in time or rate of data transmission.
Byte– is a group of 8 bits handled as a unit.
Character (Bar code)– is group of bars and spaces which represents a single number,
letter, mark or other graphic element.
Check Character or Digit– is a special character which is part of the bar code and can
be generated by an algorithm, and used to insure data integrity. When transmitted, the
same algorithm can be used by the host on the data characters and this independent
calculation can be compared to the transmitted check character. This procedure can also
be accomplished wholly within the decoder. Often the check character is not transmitted
because it is not a data character.
Codabar Start and Stop Enabled– is a decoder option. When enabled, the capital
letters representing the start and stop characters will be included in the data message.
Code ID– is a letter that designates the symbology which has been decoded. The Code
ID can be included in the data preamble or postamble to identify the scanned symbology
to the host device. Welch Allyn has a standard set of lower case Code ID’s. These are
given in Table 4.2. See also Port ID.
Code 39 Check Character Included– is a decoder option. When enabled with Code 39
check character required, the check character will be confirmed and included in the data
message.
Code 39 Check Character Required– is a decoder option. When enabled, Code 39’s
checksum will be calculated and confirmed for a valid read.
(Host) Computer– is the data system’s controlling processor which interfaces with the
decoder (either directly or through a multiplexer) and other system elements to receive
their data outputs and command their functions.
Decoder– (bar code) is a microprocessor based electronic device which translates the
electrical signals from a bar code scanner into recognizable or computer compatible data.
Decoding Enabled– is a decoder option that allows the decoding of an individual bar
code symbology to be enabled or disabled.
Density (Bar code)– refers to the number of characters in a linear inch of bar code.
Depth of Field– refers to the range of distances over which a scanner can accurately
digitize barcode. This distance is measured from the front of the scanner at the exit
window and is dependent on code size, contrast, and quality. Depth of field is equal to
the far distance minus the near distance (∆ distance).