void SetWriteTimeout(dword ms){
    COMMTIMEOUTS ct;memset(&ct,0,sizeof(ct));
    ct.WriteTotalTimeoutConstant=ms;SetCommTimeouts(fd,&ct);
  }
  void SetTimeouts(dword msRead,dword msWrite){
    COMMTIMEOUTS ct;memset(&ct,0,sizeof(ct));
    ct.ReadIntervalTimeout=ct.ReadTotalTimeoutMultiplier=MAXDWORD;
    ct.ReadTotalTimeoutConstant=msRead;
    /*ct.WriteTotalTimeoutMultiplier=MAXDWORD;*/
    ct.WriteTotalTimeoutConstant=msWrite; SetCommTimeouts(fd,&ct);
  }