code: public static boolean staticSetDTR(String port, boolean flag)
              throws UnsupportedCommOperationException {
  
          logger.fine("RXTXPort:staticSetDTR( " + port
                  + " " + flag);
          return (nativeStaticSetDTR(port, flag));
      }
docs: Extension to CommAPI This is an extension to CommAPI. It may not be
  supported on all operating systems.
  
  Open the port and set DTR. remove lockfile and do not close This is so
  some software can appear to set the DTR before 'opening' the port a
  second time later on.
  
  @param port port name
  @param flag flag value
  @return true on success
  @throws UnsupportedCommOperationException on error