The Telephone Security Group (TSG was the primary technical and policy resource in the U.S. Intelligence Community for all aspects of the TSCM (technical surveillance countermeasures) program involving telephone systems.
The charter members of the TSG were: the Department of the Air Force, Department of the Army, Central Intelligence Agency, Defense Intelligence Agency, Department of Energy, Federal Bureau of Investigation, Department of the Navy, National Security Agency, U.S. Secret Service, and Department of State.
The TSG has issued standards, which contain guidance for providing on-hook security to telephone systems in areas where sensitive government information is discussed. Implementation of TSG standards neither prevents the application of more stringent requirements nor satisfies the requirements of other security programs such as TEMPEST, COMSEC, or OPSEC.
TSG standards discussed in this wiki include:
- TSG Standard No. 1: Introduction to Telephone Security
- TSG Standard No. 2: TSG Guidelines for Computerized Telephone Systems
- TSG Standard No. 3: TSG Type-Acceptance Program for Telephones Used with the Conventional Central Office Interface
- TSG Standard No. 4: TSC Type-Acceptance Program for Electronic Telephones Used in Computerized Telephone Systems
- TSG Standard No. 5: On-Hook Telephone Audio Security Performance Specifications
- TSG Standard No. 6: TSG Approved Equipment
- TSG Standard No. 7: Guidelines for Cellular Telephones