1971 - Erroneous “Attack Warning” sent to EBS by NORAD, EBS policy changed to alerts authorized by the president only
1976 - Emergency Broadcast System automation improved with the two-tone warning signal, state and local authorities, FEMA, and NWS added to system
1983 - work starts on replacing the EBS message distribution system with the Primary Entry Points, completed in 1995
1992 - Cable Act requires cable television providers to participate in EBS, FEMA funds research into automation for unattended stations and cable headends