code: public function confParity($parity)
      {
          if ($this->_dState !== SERIAL_DEVICE_SET) {
              trigger_error(
                  "Unable to set parity : the device is either not set or opened",
                  E_USER_WARNING
              );
  
              return false;
          }
  
          $args = array(
              "none" => "-parenb",
              "odd"  => "parenb parodd",
              "even" => "parenb -parodd",
          );
  
          if (!isset($args[$parity])) {
              trigger_error("Parity mode not supported", E_USER_WARNING);
  
              return false;
          }
  
          if ($this->_os === "linux") {
              $ret = $this->_exec(
                  "stty -F " . $this->_device . " " . $args[$parity],
                  $out
              );
          } elseif ($this->_os === "osx") {
              $ret = $this->_exec(
                  "stty -f " . $this->_device . " " . $args[$parity],
                  $out
              );
          } else {
              $ret = $this->_exec(
                  "mode " . $this->_winDevice . " PARITY=" . $parity{0},
                  $out
              );
          }
  
          if ($ret === 0) {
              return true;
          }
  
          trigger_error("Unable to set parity : " . $out[1], E_USER_WARNING);
  
          return false;
      }
docs: Configure parity.
  Modes : odd, even, none
  
  @param  string $parity one of the modes
  @return bool