- Set the fRtsControl member of the DCB structure to [RTS_CONTROL_TOGGLE(0x03)] 
 using SetCommState() of the Win32API communication function.
  For details, refer to the source code of Sample 
 Program.
- For details of the DCB structure, refer to the developer's Microsoft website.
Reference : [DCB structure] (Since this is 
 an external link, the link may change without notice)
https://learn.microsoft.com/en-us/windows/win32/api/winbase/ns-winbase-dcb