serial programming

[pooch]

I am trying to write to serial port and read as well. Below is my code for it.
//mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <qextserialport.h>
#include <QDebug>
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::on_pushButton_clicked()
{
        PortSettings portSettings;
        portSettings.BaudRate = BAUD9600;
        portSettings.DataBits = DATA_8;
        portSettings.Parity = PAR_EVEN;
        portSettings.StopBits = STOP_1;
        portSettings.FlowControl = FLOW_OFF;
        //portSettings.Timeout_Millisec=1000;
 
        port= new QextSerialPort("COM3",portSettings,QextSerialPort::EventDriven);
        QObject::connect(port,SIGNAL(readyRead()),this,SLOT(readData()));
        if(port->isOpen())
        {
            port->flush();
            port->close();
        }
        port->open(QextSerialPort::ReadWrite);
        if (port->isOpen())  {
            qDebug("connected!!");
            //delay->setInterval(2000);
 
        }
        else  qDebug("not connected");
        writeData(":0B1000408000102FA00DC\r\n");//this is the data that i need to send
}
void MainWindow::readData()
{
    port->flush();
    QByteArray response=port->readAll();
    ui->textBrowser->append(response);
}
void MainWindow::writeData(char* msg)
{
    port->write(msg);
    ui->textBrowser->append("writing data");
    ui->textBrowser->append(msg);
    port->flush();
}

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <qextserialport.h>
#include <QDebug>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_pushButton_clicked()
{
        PortSettings portSettings;
        portSettings.BaudRate = BAUD9600;
        portSettings.DataBits = DATA_8;
        portSettings.Parity = PAR_EVEN;
        portSettings.StopBits = STOP_1;
        portSettings.FlowControl = FLOW_OFF;
        //portSettings.Timeout_Millisec=1000;

        port= new QextSerialPort("COM3",portSettings,QextSerialPort::EventDriven);
        QObject::connect(port,SIGNAL(readyRead()),this,SLOT(readData()));
        if(port->isOpen())
        {
            port->flush();
            port->close();
        }
        port->open(QextSerialPort::ReadWrite);
        if (port->isOpen())  {
            qDebug("connected!!");
            //delay->setInterval(2000);

        }
        else  qDebug("not connected");
        writeData(":0B1000408000102FA00DC\r\n");//this is the data that i need to send
}
void MainWindow::readData()
{
    port->flush();
    QByteArray response=port->readAll();
    ui->textBrowser->append(response);
}
void MainWindow::writeData(char* msg)
{
    port->write(msg);
    ui->textBrowser->append("writing data");
    ui->textBrowser->append(msg);
    port->flush();
}

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this code writes to virtual serial(realterm) and even reads the response. But when i use hardware to write serial data to an atmega, no response is obtained. But i received response when i sent this data to atmega using python. Is there any fault in here?