/**
  * get snom_phone_line by id
  *
  * @param string $_id the id of the line
  * @return Voipmanager_Model_Snom_Line
  */
 public function get($_id)
 {
     $id = Voipmanager_Model_Snom_Line::convertSnomLineIdToInt($_id);
     if (($result = $this->_cache->load('snomPhoneLine_' . $id)) === false) {
         $result = $this->_backend->get($id);
         $this->_cache->save($result, 'snomPhoneLine_' . $id, array('snomPhoneLine'), 5);
     }
     return $result;
 }