MSW 4V SDI rs • Serial Communication
Serial Communication
MSW 4V SDI rs • Serial Communication

3-2
3-3

Using Simple Instruction Set (SISTM) Control

Host-to-switcher communications

The Extron Simple Instruction Set (SIS) commands consist of
one or more characters per field. No special characters are
required to begin or end a command character sequence. When
a command is valid, the switcher executes the command and
sends a response to the host device. All responses from the
switcher 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.

Switcher-initiated messages

When a local event, such as a front panel operation or error
condition, occurs, the switcher responds by sending a message
to the host. The switcher-initiated messages are listed below:
(c) Copyright 2006, Extron Electronics, MSW Series Switchers,
Vx.xx]
The switcher issues the copyright message and the input
selected message when it first powers on. Vx.xx is the firmware
version number.
Inn]
The switcher sends the Inn message whenever the selected
input is changed using the front panel buttons. “n” is the input
number.

Error responses

When the switcher receives a valid SIS command, it executes
the command and sends a response to the host device. If
the switcher is unable to execute the command because the
command is invalid or it contains invalid parameters, the
switcher returns an error response to the host. The error
response codes are:
E01 – Invalid input channel number (out of range)
E06 – Invalid input channel change (auto-switch active)
E10 – Invalid command
E13 – Invalid parameter

Timeout

Pauses of 10 seconds or longer between command ASCII
characters result in a timeout. The command operation is
aborted with no other indication.

RS-232 communication

Wire the RS-232 connectors as shown below.
Switcher PC
Receive
Transmit
Ground
RS-232
Tx Rx NA
DB9 Pinout (Female)
To control equipment
5 1
9 6
Pin RS-232 Function
1 —
2 TX Transmit data (-)
3 RX Receive data (+)
4 —
5 Gnd Signal ground
6 —
7 — —
8 — —
9 — —
—
—
—
Figure 3-1 — RS-232 connector wiring
This port has the following RS-232 protocol:
• 9600 baud
• 1 stop bit
• No parity
• 8 data bits