Summary: The Department of Defense (DOD) and the North Atlantic Treaty Organization (NATO) are developing military tactical and nontactical secure voice systems; civil agencies are also developing a secure voice system. Rather than planning on the use of widely available narrowband networks for the nontactical system, DOD has sought "direct" (as opposed to "acceptable") interoperability with wideband tactical systems. After the Appropriations Committee directed development of a common-user system, DOD proposed a hybrid nontactical system concept. The Senate Committee accepted this concept, but the House Committee again directed DOD to use an all-narrowband worldwide concept. GAO supports the narrowband concept. Areas of difference with DOD are in system economies, survivability considerations, systems interoperability, NATO planning, and performance and technology trends. GAO believes that the economic and survivability advantages of a single nontactical narrowband secure voice system for military and civil agency users outweighs the advantages associated with having commonality and direct interoperability between tactical and nontactical military wideband systems. The hybrid alternative is not justified since it is more costly than the all-wideband alternative and provides little improvement in survivability.
