Extron Electronics MLC 206 AAP EC User Guide - Manual (Page 34)

MediaLink Controllers • Serial Communication 4-2
Serial Communication
The MLC can be remotely set up and controlled via a host computer or other
device (such as a control system) attached to the rear panel Configuration port.
The control device (host) can use either Extron’s Simple Instruction Set (SIS)
commands or the graphical control program for Windows.
The MLC 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 Signal ground
6, 7 – No connection
8, 9 – No connection
DB9 Pin Locations
Female
5 1
9 6
RS-232 Programmer’s Guide
Host-to-MLC 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 MLC determines that
a command is valid, it executes the command and sends a response to the host
device. All responses from the controller 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.
MLC-initiated messages
When a local event such as a front panel (or Extron switcher front panel) selection
or adjustment takes place, the MLC responds by sending a message to the host. No
response is required from the host. The MLC-initiated messages are listed here
(underlined).
(C) 2001, Extron Electronics, MediaLink Controller, Vx.xx
The MLC sends the copyright message when it first powers on. Vx.xx is the
firmware version number.
C hn X1 (where X1 is the input number)
The MLC sends this response when an input is switched.
Btn X1 (where X1 is the button number)
The MLC sends this response when a button is pressed (but the button is not part
of the switching rotation). If
X1 is 8 or greater, the button is part of an optional
control module (IRCM, ACM, RCM, or CM).
Cmd
X1
(where
X1
is the button number)
The MLC sends this response if a button is pressed while the MLC is in secondary
mode.
Error responses
When the MLC receives a valid SIS command, it executes the command and sends
a response to the host device. If the MLC 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:
E01 – Invalid input channel number (the number is too large)
E10 – Invalid command
E13 – Invalid value (the number is out of range/too large)