Network Technologies ST-nXm-U RS232 CONTROL Remote Connection, Baud Rate, None, no connection

NTI NODEMUX MULTI-USER UNIVERSAL KVM SWITCH

RS232 CONTROL

Remote Connection

The RS232 Interface is designed to meet the RS232C standard and can be controlled from any CPU or other controller with an RS232 communications port. The pin outs for the DB9 connector on the unit are as follows:

RS232 Connector (DB9 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

NOTE: Security must be disabled (see Administration Options on page 14) or user access granted (see System Access List on page 15) on the port(s) to be selected by RS-232 control.

On the DB-9 female connector, pins 1 (DCD), 4 (DTR), and 6 (DSR) are shorted and pins 7 (RTS) and 8 (CTS) are shorted. Therefore, CPU handshaking is bypassed and TXD and RXD are the only active signals. A straight through DB9 cable (not null modem) will work for most CPUs. To daisy chain multiple units, the CPU drives the input port on the first unit and the output port is connected to the input port on the next unit etc. The last unit will have a loop back plug installed in its RS232 OUT connector.

Baud Rate

The baud rate can be changed by selecting MENU on the front panel keypad. Then select 1 for SET BAUD RATE and select the desired baud rate of 9600, 4800, 2400 or 1200. A data protocol of 8 data bits, no parity, and 1 stop bit is used for communications.

Unit Address and Loop Back

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. 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 using the front panel keypad,

1.Press <MENU>

2.press <2> for “SET UNIT ADDRESS“

3.enter the address number (1-15)

4.press <ENTER>.

The "loop back" plug should be on the RS232 OUT connector on the last unit in the chain. If only one unit is being controlled, the loop back plug should be on the RS232 OUT connector on that unit.

Host

CPU

RS232

Serial

Port

RS232 RS232

IN OUT

NTI

SWITCH

Unit Address 1

RS232 RS232

IN OUT

NTI

SWITCH

Unit Address 2

Loop back

Plug installed

RS232 RS232

IN OUT

NTI

SWITCH

Unit Address 15

Figure 14- RS232 connection with "IN" and "OUT" ports

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