National Security System. Any telecommunications or information system operated by the United States Government, the function, operation, or use of which involves intelligence activities, crypto logic activities related to national security, command and control of military forces, equipment that is an integral part of a weapons system, or is critical to the direct fulfillment of military or intelligence missions. Such a system is not NSS if it is to be used for routine administrative and business applications (including payroll, finance, logistics and personnel management applications).