protected function _pingcheck()
    {
        $time = time();
        if ($time - $this->_lastrx > $this->_rxtimeout) {
            $this->reconnect();
            $this->_lastrx = $time;
        } elseif ($time - $this->_lastrx > $this->_rxtimeout/2) {
            $this->send('PING '.$this->_address, SMARTIRC_CRITICAL);
        }
    }