A call routing system employs a primary call outing device configured to receive directory assistance calls from callers at a first directory assistance system, and determines, for each of the calls, whether they will be handled by the first directory assistance system, or by a second directory assistance system among a plurality of directory assistance systems. A secondary router is also provided, configured to route the calls within the first directory assistance system to the primary call routing device The secondary router has a default call distribution logic, such that if the primary call routing device is off-line, the secondary call router routes the calls among the first directory assistance system and the plurality of directory assistance systems according to the default distribution logic.