Extron electronic IN1404XT manual Communication Protocols, Serial Control Cable Wiring

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.

		Color	Pin #
	N/C	Black	9
Scaler	N/C	Grey	8
	N/C	Purple	7		1
	N/C	Blue	6			6	To control
	Gnd	Green	5
						9	system
	N/C	Yellow	4	UC Cable	5
	RX	Orange	3
	TX	Red	2
	N/C	Brown	1	Shield	Connector Shell

One device		Up to 6 devices
Controller	Scaler	Controller	Scaler
Receive (2)	TX	Receive (2)	Each scaler's TX
Gnd (5)	Gnd	Gnd (5)	Each scaler's Gnd
Transmit (3)	RX	Transmit (3)	One scaler's RX

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.

4-2 IN1404XT Video Scaler and Switcher • Programmer’s Guide