IN ORDER FOR AN AGENCY TO IDENTIFY ITS REQUIREMENTS FOR VOICE SCRAMBLERS IT WILL HAVE TO DECIDE ON PRIVACY LEVELS, OPERATIONAL USES, AND PERFORMANCE, SPECIAL, AND SUPPORT REQUIREMENTS. IMPORTANT CONSIDERATIONS IN THESE AREAS ARE OUTLINED AND REFERENCES ARE MADE TO PREVIOUSLY PUBLISHED NILECJ-LESL (NATIONAL INSTITUTE OF LAW ENFORCEMENT AND CRIMINAL JUSTICE - LAW ENFORCEMENT STANDARDS LABORATORY) STANDARDS. DIFFERENT MODES OF SCRAMBLER FUNCTIONING, INCLUDING INVERSION, BANDSPLITTING, AND MASKING, ARE DISCUSSED. RECOMMENDATIONS ARE MADE BASED ON AGENCY REQUIREMENTS AND AVAILABILITY OF FUNDS. GUIDELINES FOR DRAFTING THE REQUEST FOR PROPOSAL, EVALUATING PROPOSALS, AND MAKING PERFORMANCE TESTS OF PROPOSED EQUIPMENT ARE PRESENTED. THE APPENDIXES CONTAIN A LIST OF REFERENCES FOR FURTHER RESEARCH, FACTORS WHICH MAY AFFECT SCRAMBLER PERFORMANCE, AND THE OUTLINE OF A COMPLETED SCRAMBLER TEST PROGRAM. (SNI ABSTRACT)...PLO