Secure Voice Telephone Systems:

How the Department of Defense Can Save Millions (Unclassified Digest of a Classified Report)

LCD-77-105: Published: Dec 30, 1977. Publicly Released: Dec 30, 1977.

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A narrowband secure voice technique is planned to protect civil agencies' telephone conversations from being monitored or intercepted by unintended listeners. The Department of Defense (DOD) selected a wideband secure voice technique to protect its own nontactical telephone conversations. This was done so that the same wideband technique could be used for communicating between nontactical and tactical secure voice systems. Generally, narrowband systems require more complex terminals needing more space and power and are more costly than wideband terminals. Conversely, wideband systems generally require more costly transmission facilities.

DOD has not fully evaluated the benefits of the narrowband alternative for its nontactical system. The wideband alternative could cost about $300 million more to protect nontactical telephone conversations than if a narrowband system were used. The benefits of having the same wideband technique for the DOD tactical and nontactical systems appear to be outweighed by the benefits of the narrowband alternative. The combined cost of both systems would be about $1.5 billion or more. The House and Senate Appropriations Committees recently directed that a single narrowband secure voice system be developed as a common-user system rather than continuing with the development of both systems.

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