Extron electronic IN1404XT - Manual (Page 58)

IN1404XT Video Scaler and Switcher • Programmer’s Guide 4-2
Programmer’s Guide
The scaler’s rear panel RS-232 3.5 mm, 3-pole captive screw connector (figure 4-1)
can be connected to the RS-232 serial port output of a host device such as a
computer running the HyperTerminal utility, an RS-232 capable PDA, or a control
system. This connection makes software control of the scaler possible.
1
5
9
6
7
6
5
4
3
2
1
8
9
Purple
Blue
Green
Yellow
Orange
Red
Brown
Grey
Black
N/C
N/C
Gnd
N/C
RX
TX
N/C
N/C
N/C
Connector Shell
Pin # Color
UC Cable
Shield
To control
system
Scaler
One device Up to 6 devices
Controller Scaler Scaler
TX Receive (2) Receive (2)
Gnd
RX
Controller
Each scaler's TX
Each scaler's Gnd Gnd (5) Gnd (5)
One scaler's RX Transmit (3) Transmit (3)
Figure 4-1 — RS-232 port pin assignments
Communication Protocols
The scaler has a factory-set baud rate of 9600 bps, but can communicate at baud
rates from 1200 bps up to 57,600 bps. Baud rates can be set from the Advance
menu, see Baud rate screen in chapter 3, Operation, and with an RS-232 command
(although communications are lost until the baud rate on the computer, PDA, or
control system are updated to the new baud rate).
The baud rate on the computer, PDA, or control system must match the baud
rate selected on the IN1404XT.
The remaining protocols, which are constant, are: 8-bit, 1 stop bit, no parity, and
no flow control.
Serial Control Cable Wiring
Figure 4-1 shows the serial control cable configured between the scaler’s 3.5 mm,
3-pole captive screw connector and a computer or control system’s 9-pin D
connector. Figure 4-1 shows the pin number in parenthesis for a PC’s standard
9-pin D connection.
When controlling multiple units, the control device or PC can only be
connected to the TX pin on one of the controlled devices; the device that is
connected is unimportant. Multiple TX lines cannot be connected together,
otherwise, signal contention will occur. Therefore, in this configuration, only
one of the controlled devices can send responses to the control system.
Each controlled device must be set to a different set of delimiters.
Command and Response Structure
The scaler accepts commands through its RS-232 port. Valid commands consist of
a leading delimnator, one or more characters in a command code, and an ending
deliminator. The control panel module’s response to an RS-232 command also
consists of a leadingdeliminator, a command code, and an ending deliminator. The
ending deliminator signals the end of either the command or the response.