#include <windows.h>
int main(int argc, char* argv[])
{
    char INBUFFER[2]; // Create Input Buffer
    char PacketOne = '\x01';

    DWORD        bytes_read    = 1024;    // Number of bytes read from port
    DWORD        bytes_written = 512;    // Number of bytes written to the port
    HANDLE       comport      = NULL;  // Handle COM port
    int          bStatus;              // Status indicator
    DCB          comSettings;          // Contains various port settings
    COMMTIMEOUTS CommTimeouts;         // Contains various COM timeouts
    // Open COM port
    if ((comport =
         CreateFile("\\\\.\\COM4",                // open com4:
                    GENERIC_READ | GENERIC_WRITE, // for reading and writing
                    0,                            // exclusive access
                    NULL,                         // no security attributes
                    OPEN_EXISTING,
                    FILE_ATTRIBUTE_NORMAL,
                    NULL)) == INVALID_HANDLE_VALUE)
    {
        printf("CreateFile() funktioniert nicht\r\n"); // error processing code goes here
        system("pause");
        exit(0);
    }

    CommTimeouts.ReadIntervalTimeout         = 0;     // Timeout in ms
    CommTimeouts.ReadTotalTimeoutMultiplier  = 0;     // Timeout in ms
    CommTimeouts.ReadTotalTimeoutConstant    = 0;   // Timeout in ms
    CommTimeouts.WriteTotalTimeoutMultiplier = 0;     // Timeout in ms
    CommTimeouts.WriteTotalTimeoutConstant   = 65000;   // Timeout in ms
    bStatus = SetCommTimeouts(comport,&CommTimeouts); // Set COM timeouts
    if (bStatus != 0)
    {
        printf("SetCommTimeouts() funktioniert nicht\r\n"); // error processing code goes here
    }
    GetCommState(comport, &comSettings); // Getting COM state
    comSettings.BaudRate = 5;           // COM setting
    comSettings.StopBits = ONESTOPBIT;  // COM setting
    comSettings.ByteSize = 7;           // COM setting
    comSettings.Parity   = EVENPARITY;    // COM setting
    comSettings.fParity  = FALSE;       // COM setting
    bStatus = SetCommState(comport, &comSettings); // Setting COM state
    if (bStatus == 0)
    {
        printf("SetCommState() funktioniert nicht.\r\n"); // error processing code goes here
    }
    while(!kbhit()) // Solange keine Taste gedrückt wird
    {
        /////Kommunikation
        comSettings.BaudRate = 9600;           // COM setting
    bStatus = SetCommState(comport, &comSettings); // Setting COM state

        bStatus = ReadFile(comport,&INBUFFER,2,&bytes_read,NULL);
        printf("Receiving: %d <-> %d\r\n", INBUFFER[0], INBUFFER[1]);

        system("pause");

        bStatus = WriteFile(comport,&PacketOne,1,&bytes_written,NULL);
        printf("Sending: %d\r\n", PacketOne+169);

        system("pause");
    }
    CloseHandle(comport);
 return 0;
}