Voice privacy equipment for law enforcement communication systems
George R. Sugar · 1973
Law enforcement agencies are finding increasing need for voice -scrambling equipment to provide privacy on their two-way radio communication systems.Work is underway at the National Bureau of Standards, under the sponsorship of the National Institute of Law Enforcement and Criminal Justice (NILECJ) , to develop performance standards for voice scramblers.The four areas being considered are intelligibility, voice quality, privacy, and general system characteristics.This report first defines a set of special terms, then describes a number of types of scramblers that are now available for law enforcement use.Some inherent problems and weaknesses are discussed.The concepts of intelligibility and privacy are explored in detail.The potential contents of the standard are described, and some problems inherent in preparing and using the standard are discussed.The report concludes with some material intended to be of immediate assistance to the prospective purchaser of scramblers:a survey of units now on the market, some hints on how to proceed in the absence of a standard, and a bibliography of technical publications on voice scrambling.