Barco RS232 1. SERIAL COMMUNICATIONS BASICS

1. Se rial communications Basics

1. SERIAL COMMUNICATIONS BASICS

Overview

• Communication Protocol

• Data words

• Communication settings

• Hardware

• Syntax

• Serial comms commands

Like every communication method the serial communication uses a particular protocol (ANSI) which must be respected in order to

allow communication to take place, following table gives a summary of the predefined communication terms.

Start byte \xfe

Projector address

Command byte(s)

Data bytes1

Checksum byte

Stop byte \xff

ANSI

American National standards Institute

The “Start byte” informs the projector(in case o f transmission)o r the computer (in case of reception) that a new data transfer will

take place

The “projector address” defines the address of the computer the projector wants to talk to (in case of transmission) or the address

of the projector that answers (in case of reception).

The maximum number of projectors that can be addressed by one computer is 256.

There is atlea stone co mmand byte to define thea ction tob epe rformed. Commands that are not often used or complex commands

can take more than one byte. All command bytes that are sent by the computer to get information out of the projector are repeated

in the answer-data-transfer of the projector.

Whether the command bytes are followed by one or more data bytes depends on the contents of the command bytes.

Data which contains more than one byte is called a word and can also be signed or unsigned.see "Data words", page 6

1. optional

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