EZT-570S User Communication Reference Manual
3
1. Introduction
This document is targeted towards new users interested in using data communications with CSZ
EZT-570S controllers. The purpose of this manual is to enable users to:
1. Understand the basics of data communications via standard definitions, interfaces and
protocols.
2. Set up and use a simple network of one or more EZT-570S controller(s).
In this manual, numbers in the format 0x00 represent values in hexadecimal. Numbers in the format
0 represent values in decimal and finally, numbers in the format 00000000 represent values in binary
unless otherwise stated.
1.1 Definition
of
Terms
Machine-to-Machine Communication
In order for machines to communicate with each other, they need a code called a character format or
character set. They need rules called protocol to govern their conversation and prevent confusion and
errors. Computers need a connecting interface over which to communicate. They may use one pair
of wires to send information in one direction and another pair to send in the opposite direction (full
duplex). Or they may use one pair to send in both directions (half duplex).
Character Format
The code or character format for the EZT-570S data communication is shared by virtually everyone in
the electronics industry. This code defines a computer stream of 1’s and 0’s that are created by
varying a voltage signal in a regular manner. This code is the American Standard Code for
Information Interchange, called ASCII.
Bits and Bytes
The word bit is simply the contraction of the words binary digit. A bit is the basic unit in ASCII. It is
either a “1” or a “0”. A byte is a string of eight bits that a computer treats as a single character. ASCII
can use a single byte to represent each letter of the alphabet, each digit and each punctuation mark
we use.
ASCII
The ASCII code defines 128 separate characters, one for each letter, digit and punctuation mark.
ASCII also includes control characters similar to those we find on computer keys, such as backspace,
shift and return. It also has nine communications control characters for identification, enquiry
(inquiry), start of text, end of text, end of transmission, acknowledge, negative acknowledge and
escape. The ASCII code is sometimes written in a base 16 number system that is called
hexadecimal or “hex” for short. The numbers 0 through 9 represents the first ten digits of this system,
and the letters A through F represents the final six digits. The 128 ASCII character codes with the
decimal, binary and hexadecimal equivalents are listed in the following table.
ASCII Control Codes
ASCII Control Codes are used to give instructions to the remote device and result in specific actions,
such as a line feed instruction on a printer. ASCII Control Codes, the first 33 ASCII characters (non
printable), are important for the operation of communicating equipment. They give instruction to
remote devices that result in specific actions such as a line feed on a printer. Holding down the
keyboard control key while pressing the appropriate keyboard key is what sends these values.
