Network Technologies SM-8X4-HDA RS232 Control, Remote Connection, Baud Rate, Unit Address

NTI AUDIO/HD VIDEO MATRIX SWITCH

RS232 Control

Remote Connection

The RS232 Interface is designed to control the switch via serial (RS232) daisy chain connection from any host computer or other controller with an RS232 communications port. There is, however, a restriction that must be followed:

A program must be used that will send an entire command line all at once, not character by character. (The HyperTerminal program in WINDOWS cannot be used, as it sends each character one at a time.)

The pin outs for the DB-9 connector on the unit are as follows:

RS232 Connector (DB-9 FEMALE)

PIN SIGNAL FUNCTION

1	None	no connection
2	TXD	Transmit Data (RXD at host)
3	RXD	Receive Data (TXD at host)
4	DSR	Data Set Ready
5	GND	Signal Ground
6	DTR	Data Terminal Ready
7	CTS	Clear to Send
8	RTS	Request to Send
9	none	no connection

On the DB-9 female connector, pins 4 (DSR) and 6 (DTR) are shorted and pins 7 (CTS) and 8 (RTS) are shorted. Therefore, host handshaking is bypassed and TXD and RXD are the only active signals. A straight through DB-9 cable (not null modem) will work for most CPUs. To daisy chain multiple units, use NTI Matrix-Y-1 "Y" cables, except for the last unit connected. (see Fig 6). For a pinout of the Matrix-Y-1 cable, see page 31. For straight through cable pinouts applicable to various terminal types, see page 30.

Baud Rate

The unit powers up with a default baud rate of 9600 and a fixed data protocol of 8 data bits, no parity and 1 stop bit. The baud rate can be changed by pressing the MENU button on the front panel keypad. Then select 1 for SET BAUD RATE and select the desired baud rate of 9600, 2400, 1200 or 300. A data protocol of 8 data bits, no parity, and 1 stop bit is used for communications.

Unit Address

To allow multiple units to be controlled from a single CPU port, the RS232 control interface is designed to allow "daisy chaining" up to 15 units using the NTI Matrix-Y-1 "Y" cables (sold separately- pin out is on page 28). By setting the appropriate unit address with the keypad, each unit can be given a unique address (1-15). Then the unit will only respond to commands on the bus if its address is embedded in the command. To set the unit address select MENU on the front panel keypad. Then select 2 for SET UNIT ADDRESS and then type the address number (1-15) and (ENTER).

RS232	Matrix-Y-1	Matrix-Y-1	Matrix-Y-1
CPU Serial Port

RS232	RS232	RS232
NTI	NTI	NTI
SWITCH	SWITCH	SWITCH
First Unit	Second Unit	Last Unit

Figure 7- RS232 connection with Matrix-Y-1 cable

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