EZT-570S User Communication Reference Manual
A.2
Terms and Definitions
Address –
A unique designator for a location of data or a controller that allows each location or
controller on a single communications bus to respond to its own message.
ASCII
(pronounced AS-KEY) – American Standard Code for Information Interchange. A universal
standard for encoding alphanumeric characters into 7 or 8 binary bits.
Asynchronous –
Communications where characters can be transmitted at an unsynchronized point
in time. In other words, it can start and stop anytime. The time between transmitted characters may
be of varying lengths. Communication is controlled by “start” and “stop” bits at the beginning and end
of each character.
Baud –
Unit of signaling speed derived from the number of events per second (i.e., bits per second).
Baud rate –
The rate of information transfer in serial communications, measured in bits per second.
Binary –
Number based system where only two characters exist, 0 and 1. Counting is 0, 1, 10, 11...
Bit –
Derived from “B I nary digi T”, a one or zero condition in the binary system.
Byte –
A term referring to eight associated bits of information, sometimes called a “character”.
Character –
Letter, numeral, punctuation, control figure or any other symbol contained in a message.
Typically this is encoded in one byte.
Communications –
The use of digital computer messages to link components. (See serial
communications and baud rate)
Converter –
This device will convert from one hardware interface to another such as from EIA-232 to
EIA-485. The converter may be transparent to the software, which means you do not have to give
any special considerations to software programming.
CRC –
When data is corrupted during transmission, a method is used to return the data to its correct
value. This can be accomplished through several methods: parity, checksum and CRC (cyclic
redundancy checksum) are three of these. C yclic R edundancy C hecksum is an error-checking
mechanism using a polynomial algorithm based on the content of a message frame at the transmitter
and included in a field appended to the frame. At the receiver, it is then compared with the results of
the calculation that is performed by the receiver.
Data –
The information that is transferred across the communications bus. This may be a setpoint,
setup parameter, or any character. This information is transferred to an address or register.
DB-9 –
A standardized connector shaped like the letter “D” when viewed on edge. This connector
has 9 contacts. It is utilized on most IBM AT compatible PCs as the serial port.
DB-15 –
A standardized connector shaped like the letter “D” when viewed on edge. This connector
has 15 contacts. It is utilized on most IBM AT compatible PCs as the game/midi port.
DB-25 –
A standardized connector shaped like the letter “D” when viewed on edge. This connector
has 25 contacts. It is utilized on most IBM AT compatible PC’s as the parallel port when the PC end
contains socket contacts. Can also be the serial port when the PC end contains pin contacts.
Terms and Definitions (cont’d)
