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).
