Extron Electronics VTG 400D_400 DVI User Guide - Manual (Page 38)

VTG 400D/400 DVI • Serial Communication 3-2
Serial Communication
The VTG can be remotely controlled via a host computer or other device (such as
a control system) attached to the rear panel RS-232 connector. The control device
(host) can use either the Extron Simple Instruction Set (SIS ™ ) commands or the
graphical control program for Windows ® .
The VTG uses a protocol of 9600 baud, 1 stop bit, no parity, and no flow control.
The rear panel RS-232 9-pin D connector has the following pin assignments:
Pin RS-232 function Description
1 – No connection
2 Tx Transmit data
3 Rx Receive data
4 – No connection
5 Gnd Sign al ground
6 – No connection
7 – No connection
8 – No connection
9 – No connection
RS-232 Programmer’s Guide
Host-to-VTG communications
SIS commands consist of one or more characters per field. No special characters
are required to begin or end a command sequence. When the VTG determines
that a command is valid, it executes the command and sends a response to the
host device. All responses from the video test generator to the host end with a
carriage return and a line feed (CR/LF = ), which signals the end of the
response character string. A string is one or more characters.
It is also possible to send several SIS commands back-to-back in sequence.
Video test generator-initiated messages
When a local event such as a top panel selection or adjustment takes place, the
VTG responds by sending a message to the host. No response is required from
the host. An example of a video test generator-initiated message is listed here
(underlined).
(C) Copyright 2004, Extron Electronics, VTG 400, Vx.xx
The VTG sends the copyright message when it first powers on. Vx.xx is the
firmware version number.
Error responses
When the video test generator receives a valid SIS command, it executes the
command and sends a response to the host device. If the VTG is unable to
execute the command because the command is invalid or it contains invalid
parameters, it returns an error response to the host.
The error response codes and their descriptions are as follows:
E05 – VTG 400 power is off and an attempt has been made to send it a command.
E07 – An attempt to select a nonexistent test pattern number has been made.
E08 – An attempt to select a nonexistent scan rate number has been made.
E10 – Invalid command
E11 – Invalid preset #
E13 – Invalid value (out of range)
E23 – Checksum error
DB9 Pin Locations
Female
5 1
9 6