The tests of the system lasted 35 or 40 seconds, with TV stations usually displaying a test pattern and announcing that a test is under way. A loud high-pitched obnoxious tone followed, followed by the familiar phrase "This is a test of the Emergency Broadcast System. If this had been an actual emergency... ." In an actual emergency the public would be given Civil Defense instructions. The system was never used for a nuclear emergency, though it was activated more than 20,000 times between 1976 and 1996 to broadcast civil emergency messages and warnings of severe weather hazards.
All radio and television stations must perform the Weekly Transmission Test Of The Attention Signal and Test Script a minimum of once a week at random days and times between 8:30 A.M and local sunset, unless during the test week, they have activated the EBS for a state or local emergency or participated in a coordinated State or local EBS test.
1) DISCONTINUE NORMAL PROGRAM
2) BROADCAST THIS ANNOUNCEMENT "This is a test. This station (optional -- insert station call sign) is conducting a test of the Emergency Broadcast System. This is only a test." (TV stations shall display an appropriate EBS slide and transmit all announcements visually and aurally in the manner required by Section 73.1250(h) of the FCC rules. Stations which provide foreign language programming may transmit emergency announcements in the foreign language prior to broaadcasting such announcements in English.)
3) TRANSMIT ATTENTION SIGNAL Broadcast the two-tone Attention signal from the EBS encoder for 20 to 25 seconds (see Sections 73.906 and 73.940 of the Rules).
4) BROADCAST ANNOUNCEMENT "This is a test of the Emergency Broadcast System. The broadcasters of your area in voluntary cooperation with the Federal, State and local authorities have developed this system to keep you informed in the event of an emergency. If this had been an actual emergency, (optional -- stations may mention the types of emergencies likely to occur in their area) the Attention Signal you just heard would have been followed by official information, news or instructions. This station (optional -- insert station call sign) serves the (operational area name) area. This concludes this test of the Emergency Broadcast System."
Under the EBS, the program equipment that allowed the President to reach the public through their local broadcasters was required at broadcast stations licensed by the FCC. This equipment produced what was commonly called a two-tone signal (the frequencies 853Hz and 960Hz played simultaneously) that was broadcast by stations on the main audio channel, and served the dual purpose of getting the listeners attention and activating other EBS equipment in the listening area. Upon activation of the EBS equipment, a station would listen and record the accompanying audio message and could then retransmit this message for their audience. In general, EBS equipment could do little more then reproduce the dual tone signal and record the messages it receives upon activation. EBS equipment can only monitor one source for alerts. Once a station receives an EBS message it must broadcast the EBS message and two-tone signal in order for the next station to receive the information. If a station fails to activate their EBS equipment, the chain will be broken and a segment of the population will not receive the emergency information through EBS. Although the EBS system was established for national messages, many broadcasters and local officials recognized that the system could be used to notify listeners about local emergency situations. As of the beginning of 1996 the FCC had received 20,341 reported activations of EBS (since 1976). Approximately 85% of these activations were for weather related emergencies. The number of activations was most assuredly higher as stations were not required to report their usage of the system.