src/PhpSerial.php
public function setSetserialFlag($param, $arg = "")
    {
        if (!$this->_ckOpened()) {
            return false;
        }

        $return = exec(
            "setserial " . $this->_device . " " . $param . " " . $arg . " 2>&1"
        );

        if ($return{0} === "I") {
            trigger_error("setserial: Invalid flag", E_USER_WARNING);

            return false;
        } elseif ($return{0} === "/") {
            trigger_error("setserial: Error with device file", E_USER_WARNING);

            return false;
        } else {
            return true;
        }
    }
public function setSetserialFlag($param, $arg = "")
    {
        if (!$this->_ckOpened()) {
            return false;
        }

        $return = exec(
            "setserial " . $this->_device . " " . $param . " " . $arg . " 2>&1"
        );

        if ($return{0} === "I") {
            trigger_error("setserial: Invalid flag", E_USER_WARNING);

            return false;
        } elseif ($return{0} === "/") {
            trigger_error("setserial: Error with device file", E_USER_WARNING);

            return false;
        } else {
            return true;
        }
    }
Sets a setserial parameter (cf man setserial)
NO MORE USEFUL !
-> No longer supported
-> Only use it if you need it

@param  string $param parameter name
@param  string $arg   parameter value
@return bool