1. In public switched networks, regarding circuits that span long distances, such as the circuits in inter-LANA, interstate, and international communications. 2. In military use, communications among users on a national or worldwide basis. Long-haul communications are characterized by a higher level of users, more rigorous performance requirements, longer distances between users, including world wide distances, higher traffic volumes and densities, larger switches and trunk cross sections, and fixed and recoverable assets. Usually pertains to the U.S. Defense Communications System.