Glossary-3

Glossary
ACK/NAK ACK/NAK is the default software handshaking.
Aperture The opening in an optical system defined by a lens or baffle that
establishes the field of view.
ASCII American Standard Code for Information Interchange. A 7 bit-plus-
parity code representing 128 letters, numerals, punctuation marks,
and control characters. It is a standard data transmissio n c ode in th e
U.S.
Autodiscrimination The ability of an interface controller to determine the code type of a
scanned bar code. After this determination is made, the information
content is decoded.
Bar The dark element in a printed bar code symbol.
Bar Code Density The number of characters represented per unit of measurement
(e.g., characters per inch).
Bar Height The dimension of a bar measured perpendicular to the bar width.
Bar Width Thickness of a bar measured from the edge clo sest to the symbol st art
character to the trailing edge of the same bar.
Baud Rate A measure of the data flow or number of signaling events occurring
per second. When one bit is the standard "event," this is a measure o f
bits per second (bps). For example, a baud rate of 50 means
transmission of 50 bits of data per second.
Bit Binary digit. One bit is the basic unit of binary information . Ge ner all y,
eight consecutive bits compose one byte of dat a. The pa ttern of 0 and
1 values within the byte determines its meaning.