14 March 1962: Draft D Sigs Technical Bulletin 63/Protected Leased Circuits

The practical side of protecting leased army telephone circuits is addressed in this technical report. A protected leased circuit was defined as “one which is so important that its interruption for more than a very short time (in order of five minutes) will seriously affect the readiness of the Government or the Army, and/or seriously impede Defence or Survival capability.” This included “certain special alerting, warning, and intelligence circuits.” The Directorate of Signals was to work with the Emergency Measures Organization to identify and select circuits for protection. Telephone companies were to pitch in as well – supervising, protecting, and working with D Sigs to restore any downed circuits in the event of an emergency.