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SI-PROFINET RT User Guide
Issue Number: 2
9
Glossary
Address
: This is the unique network identification given to a networked device to allow
communication on a network. When a device sends or receives data the address is
used to determine the source and the destination of the message.
ASCII (American Standard Code for Information Interchange)
: A standard character
encoding mechanism established by ANSI to provide compatibility between data
systems and services.
Asynchronous Transmission
: Each character transmitted is individually synchronized
using start and stop bits.
ANSI (American National Standards Institute)
: A voluntary organization that
represents the USA in the ISO, and is responsible for defining ASCII. Members include
manufacturers, common carriers, and other standards organizations such as the IEEE.
Auto-crossover detection
: A method used to automatically detect if a crossover or
non-crossover network cable is connected.
Bandwidth
: The information-carrying capability of a communications channel or line,
expressed in Hertz (Hz), between the highest and lowest frequencies of a band.
Baseband Transmission
: Direct transmission method whereby the transmission
medium carries only one signal at a time usually for distances under ten miles.
BCC (Block Check Character)
: A control character added to a block in character
oriented protocols used for determining if the block was received in error -- such as
CRC and LRC.
BCD (Binary Coded Decimal)
: A digital system that uses six-bit binary codes to
represent decimal digits, providing 64 possible combinations.
Binary
: A digital system with two states, 1 and 0.
Bit
: A contraction of the phrase binary digit, representing the smallest unit of information
and the basic unit in data communications, a bit may have the value of 1 or 0.
Bit Rate
: The speed at which binary digits (bits) would be transmitted over a
communications path and usually expressed in "bits per second" (bps). Bit rate should
not be confused with Baud which defines the rate of signal state changes.
Byte
: A collection of 8 binary digits that collectively store a value. This may be signed or
unsigned.
CCITT (The Consultative Committee International Telegraph and Telephone)
: The
international advisory committee, established under the United Nations that sets
international recommendations which often are accepted as standards.
