Which of the following is not a requirement of a secure telephone system in a SCIF?

• A. Encrypted Voice Transmissions for All Calls
• B. Proper Destruction of Recorded Conversations
• C. Detects Attempted or Actual Unauthorized Human Entry into a SCIF
• D. Regular Maintenance and Testing of Secure Lines

Answer: (C)

Secure telephone systems in a SCIF are focused on protecting the voice communications themselves—keeping them confidential, intact, and available for authorized users. Encrypted voice transmissions for all calls ensures confidentiality, so even if the line is tapped, the content remains unread. Proper destruction of recorded conversations prevents sensitive material from lingering and potentially leaking after the fact. Regular maintenance and testing of secure lines keeps the encryption devices and secure channels functioning correctly, reducing the chance of vulnerabilities that could expose conversations. Detecting attempted or actual unauthorized human entry into a SCIF, while essential to overall SCIF security, is a physical security function rather than a feature of the secure telephone system itself. Alarm systems, access controls, and guards handle entry detection, whereas the telephone system’s role centers on safeguarding the voice communications.