VSC 75 Serial Communication
VSC 75 Serial Communication
Remote Control, cont’d
3-3

VSC error responses

When the VSC 75 receives a valid SIS command, it executes
the command and sends a response to the host device. If
the VSC 75 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:
E09 – Invalid function number (the number is too large)
E10 – Invalid command
E13 – Invalid value (the number is out of range).

Time-out

A delay of 10 or more seconds between command sequence
characters causes a time-out. The command operation is
stopped, and there is no indication that a time-out occurred.

Using the command/response table

The command/response table on the next page lists valid
command ASCII codes, the VSC 75’s responses to the host,
a description of the command’s function or the results of
executing the command, and an example of each command.
Lower case characters are acceptable in the command field
only where indicated.
The ASCII to HEX conversion table below is for use with
the command/response table.
ASCII to HEX Conversion Table
•
Serial Communication
3-2
DB9 Pin Locations
Female
51
96
The VSC 75 can be controlled by a host computer or other
control device via an RS-232 connection with a protocol of
9600 baud, 1 stop bit, no parity, and no flow control. The
control device (host) can use either Extron’s Simple
Instruction Set (SIS) or the graphical control program for
Windows.
The rear panel RS-232 9-pin D connector has
the following pin assignments:
Pin RS-232 function Description
1 – Not used
2 Tx Transmit data
3 Rx Receive data
4 – Not used
5 Gnd Signal ground
6 – Not used
7 – Not used
8 – Not used
9 – Not used

RS-232 Programmer’s Guide

SIS commands consist of one or more characters per field.
No special characters are required to begin or end a
command sequence. When the VSC 75 determines that a
command is valid, it executes the command and sends a
response to the host device. All responses from the scan
converter 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.

VSC-initiated messages

When a local event such as a front panel selection or
adjustment takes place, the VSC 75 responds by sending a
message to the host. No response is required from the host.
The VSC-initiated messages are listed here (underlined).
(C) COPYRIGHT 2000, EXTRON ELECTRONICS VSC 75,
Vx.xx
The VSC 75 displays the copyright message when it first
powers on. Vx.xx is the firmware version number.
RECONFIG The VSC 75 sends the Reconfig message
when the input source is changed and when changes have
been made to one or more of the settings.