Extron • System 4
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Switcher Series • User’s Manual
Appendix A • RS-232 Programmer’s Guide
Programming the System 4
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Series Switchers
This section covers the commands for a host to setup and control a System 4
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series switcher through the RS-232 port. The material included covers the
System 4LD
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and the System 4LQ
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switchers. Commands or parameters that
apply to specific models will be pointed out, otherwise, all references will simply
say “System 4
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”.
RS-232 Connections
A standard RS-232 port is
available on the back of
the System 4
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for use by
a host system. The
connections are as
follows:
Figure A-1. The RS-232, 9-pin D Connector on the Rear Panel
RS-232 Pin Connections
Pin
Signal
Pin
Signal
Pin
Signal
1
n/c
4
Tx2
7
n/c
2
Tx
5
Gnd
8
Rx2
3
Rx
6
n/c
9
n/c
_______ Rx2 and Tx2 are used to communicate with a slave switcher (do not connect to
or use these pins)
RS-232 Protocol
The default protocol is:
9600 baud, 8-bits, no parity, 1 stop bit and no flow-control.
The baud rate can be changed through a front panel menu. (See Chapter 3.)
Program Instruction Levels
The System 4
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recognizes any character that comes in on the RS-232 port as a
possible command. Commands can be from either of two groups, or instruction
sets. They are as follows:
1. The Simple Instruction Set can be any ASCII character that is recognized
by the System 4
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as a command. For this set, there are no codes required
to say that a command is coming, or that a command has ended. Simple
commands could come from a terminal, or any other controlling device. After
the System 4
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gets the command, it will execute it and send an appropriate
response to the controlling device.
2. The Advanced Instruction Set consists of more complex instruction strings.
Advanced instructions are used when a complete command cannot be
defined within one character. Each instruction string must begin with an
Escape code (ESC) and end with an End Of Transmission code (EOT).
Advanced commands could come from any controlling device capable of
composing a command and sending it as a string. The System 4
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will
execute any legal command string and send a response string back to the
host.
Because of this “open recognition”, commands from the two instruction sets can
be intermixed. Both instruction sets are listed and defined on pages that follow.
_______ RS-232 control can also be established from a computer using the Windows®
operating system and Extron’s software. This is covered separately in Chapter 5.
OUTPUT
OUTPUT
AUDIO
AUDIO
A-1
