How to send command to standard serial port

[wf321]

Dear Sir:

1. I had a hardware(switch), direct connect to computer com1 using R485 line.
2. I can turn the switch on/off using standard serial test code.
3. I can also using following rxtx( same version as scadabr using) java code to turn it on/off.

now with mango, I created modbus serial data source, and it can scan found 1 node. But when create data point,
there is no "output" option for "Register range", so I do not know how to continue.

would you please help me how to create data source ( modbus serial or .. ?) ,
data point and script to turn the switch on/off ?

Thanks a lot.
william
wf321@163.com

*********************************** RXTX CODE ****************************
import gnu.io.CommPort;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;

import java.io.FileDescriptor;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public static void main ( String[] args )
{
connect("COM1");
}

void connect ( String portName ) throws Exception
{
    CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier(portName);
    CommPort commPort = portIdentifier.open(this.getClass().getName(),2000);

            SerialPort serialPort = (SerialPort) commPort;

serialPort.setSerialPortParams(4800,SerialPort.DATABITS_8,SerialPort.STOPBITS_2,SerialPort.PARITY_NONE);

            System.out.println(serialPort.getName());
            InputStream in = serialPort.getInputStream();
            OutputStream out = serialPort.getOutputStream();
            
            // send 8 int to control the switch
            int len = 8;
            int[] buffer = new int[len];


            buffer[0] = 0x01;  // com1
            buffer[1] = 0x05;  
            buffer[2] = 0x00;  // port 0
            buffer[3] = 0x01;  // channel
            buffer[4] = 0xff;  // turn the switch on , 0X00 means tuen off
            buffer[5] = 0x00;
            buffer[6] = 0xdd;  // check use crc16
            buffer[7] = 0xfa;  // check use crc16

            
            for (int i = 0; i < len; i++)
            {
                System.out.println(buffer*);
             out.write(buffer*);
            }
            out.flush();
            
            commPort.close();
}

[mlohbihler]

"output" is not a valid register range. "Input status" and "Input register" are the read-only register ranges.