An Introduction to Secure Telephone Terminals

This bulletin addresses several frequently asked questions about secure telephone terminals, discusses practical security issues from a federal user's viewpoint, and provides sources for additional information. A secure telephone terminal is a device that connects to a telephone line or a cellular telephone system and provides a variety of security services to the conversation or information being transmitted. Secure telephone terminals are becoming more widely available for the protection of both classified and unclassified voice, data, and facsimile (fax) communications (most modern secure telephones have a data port for connecting to computers or fax machines). The secure terminals range in capability from protecting conversations between the handset and the base terminal in cordless telephones to protecting national security classified information in fixed and mobile telecommunications.