Extron electronic DVS 204 12V Serial Communication, RS-232 Programmer’s Guide, Error responses

Serial Communication

The DVS 204 can be remotely controlled via a host computer or other device (such as a control system) attached to the rear panel Remote connector. The control device (host) can use either Extron’s Simple Instruction Set (SIS) commands or the graphical control program for Windows.

The scaler 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	Input #1	Contact closure	5	1
2	Tx	Transmit data
3	Rx	Receive data
4	Input #2	Contact closure	9	6
5	Gnd	Signal ground	DB9 Pin Locations
6	Input #3	Contact closure	Female
7	Input #4	Contact closure
8	–	No connection
9	Hardwired IR	IR input

RS-232 Programmer’s Guide

Host-to-scaler 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 DVS 204 determines that a command is valid, it executes the command and sends a response to the host device. All responses from the scaler 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.

Scaler-initiated messages

When a local event such as a front panel selection or adjustment takes place, the DVS 204 scaler responds by sending a message to the host. No response is required from the host. The scaler-initiated messages are listed here (underlined).

(C) Copyright 2002, Extron Electronics, DVS 204, Vx.xx

The DVS 204 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 DVS 204 sends this response when an input is switched.

Error responses

When the scaler receives a valid SIS command, it executes the command and sends a response to the host device. If the DVS 204 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

E11 – Invalid preset number

E13 – Invalid value (the number is out of range/too large)

E17 – Illegal command for this signal type.

3-2 DVS 204 • Serial Communication