Emergency Broadcast System The Emergency Broadcast System ( EBS ) was an emergency warning system used in the United States that replaced the CONELRAD system . EBS was used from 1963 to 1997 , at which point EBS was replaced by the Emergency Alert System . Purpose . " The system was established to provide the President of the United States with an expeditious method of communicating with the American public in the event of war , threat of war , or grave national crisis . " It replaced CONELRAD on August 5 , 1963 . In later years , it was expanded for use during peacetime emergencies at the state and local levels . Although the system was never used for a national emergency , it was activated more than 20 , 000 times between 1976 and 1996 to broadcast civil emergency messages and warnings of severe weather hazards . Some dramatic works depicting nuclear warfare ( most notably the 1983 made - for - TV film " The Day After " ) included fictionalized scenes of EBS activations . Occasionally the EBS would be shown in fictionalized use for events other than nuclear warfare , such as the 1978 " Dawn of the Dead " . National Level EBS . An order to activate the EBS at the national level would have originated with the President and been relayed via the White House Communications Agency duty officer to one of two origination points : either the Aerospace Defense Command ( ADC ) or the Federal Preparedness Agency ( FPA ) — as the system stood in 1978 . Participating telecommunications common carrier s , radio and television networks , the Associated Press and United Press International would receive and authenticate ( by means of code words ) an Emergency Action Notification ( EAN ) via an EAN teletypewriter network designed specifically for this purpose . These recipients would relay the EAN to their subscribers and affiliates . The release of the EAN by the Aerospace Defense Command or the Federal Preparedness Agency would initiate a process by which the common carriers would link otherwise independent networks such as ABC , CBS and NBC into a single national network that even independent stations could receive programming from . " Broadcast stations would have used the two - tone Attention Signal on their assigned broadcast frequency to alert other broadcast stations to stand by for a message from the President . " The transmission of programming on a broadcast station ' s assigned frequency , and the fact that television networks / stations could participate , distinguished EBS from CONELRAD . EBS radio stations would not transmit on 640 or 1240 AM , and television stations would carry the same audio program as AM radio stations . Activation procedure . Actual activations originated with a primary station , which would transmit the . The Attention Signal most commonly associated with the system was a combination of the sine waves of 853 and 960 Hz , an interval suited to getting the audience ' s collective attention due to its unpleasantness on the human ear . Decoders at relay stations would sound an alarm , alerting the station operator to the incoming message . Then each relay station would broadcast the alert tone and rebroadcast the emergency message from the primary station . A nationwide activation of the EBS was called an Emergency Action Notification ( EAN ) , and was the only activation that stations were not allowed to ignore ; the FCC made local civil emergencies and weather advisories optional , ( except for stations that agreed to be the " primary " source of such messages ) . To activate the EAN protocol , the AP and UPI wire service s would notify stations with a special message . It began with a full line of X ' s , and a bell inside the Teletype machine would sound ten times . To avoid abuse and mistakes , the message included a confirmation password which changed daily . Stations that subscribed to one of the wire services were not required to activate the EBS if the activation message did not have proper confirmation . False alarm of 1971 . Despite these safeguards , the system was accidentally activated at 9 : 33 AM EST on Saturday 20 February 1971 . Teletype operator W . S . Eberhardt " played the wrong tape " during a test , which sent an activation message authenticated with the codeword " hatefulness " through the entire system , ordering stations to cease regular programming and broadcast the alert of a national emergency . A cancellation message was sent at 9 : 59 AM EST , but it used an incorrect codeword . A cancellation message with the correct word , " impish " , was not sent until 10 : 13 AM EST After 40 minutes and six incorrect cancellation messages the accidental activation was terminated . This false alarm demonstrated major flaws in the EBS . Many stations had not received the alert but more importantly , the vast majority of those that did either ignored it ( because it came at the time of a scheduled test ) , or did not know what to do in an emergency . Some stations followed the procedures for an activation but cancelled prematurely . It is estimated that only 20 % followed the procedures completely . While several stations went off the air , the one best remembered was WOWO in Ft . Wayne , Indiana , which broadcast the 1971 events as they happened , a recording of which has become available . Another recording of how the error sounded on WCCO - AM Minneapolis / St . Paul , MN can be heard on RadioTapes . com . Numerous investigations were launched , and several changes were made to the EBS . Among them , the on - air alert announcement was streamlined , eliminating one version of the script that warned the audience of an imminent attack against the country . ( The WOWO broadcast above does not contain the reference to an attack . ) System uses . Although it was never used , the FCC ' s EBS plan involved detailed procedures for stations to follow during an EAN . It included precise scripts that announcers were to read at the outset of the emergency , as well as whenever detailed information was scarce . Among other things , citizens were instructed not to use the telephone , but rather continue listening to broadcast stations for information . The initial scripted announcement was : " We interrupt this program . This is a national emergency . The President of the United States or his designated representative will appear shortly over the Emergency Broadcast System . " As official information began to emerge from various sources , non - primary stations were to broadcast it according to the following priority list : A presidential message was always required to be aired live during an EAN . For other information , stations were to follow the priority list to decide what should be disseminated first . Lower priority official programming was to be recorded for the earliest available rebroadcast . Participation in EAN emergency broadcasting was done with the " voluntary cooperation " of each station ( as noted in the classic test announcement ) . Stations that were not prepared to be part of the national EBS network were classified as " non - participating " by the FCC . During an EAN , a non - participating station was required to advise listeners / viewers to tune elsewhere to find emergency bulletins . The station ' s transmitter would then be turned off . Non - participating stations had to remain off - the - air until the EAN was terminated . Under no circumstances could any broadcast station continue with normal programming during a national emergency . Testing the system . Until the system was superseded , radio and television stations were required to perform a " Weekly Transmission Test Of The Attention Signal and Test Script " on random days and times between 8 : 30 A . M and local sunset . Stations were required to perform the test at least once a week , and were only exempt from doing so if they had activated the EBS for a state or local emergency , or participated in a coordinated state or local EBS test during the past week . Additionally , stations were required to log tests they received from each station they monitored for EBS messages . This served as an additional check , as they could expect to hear a weekly test from each source . Failure to receive a signal at least once a week meant that either the monitored station was having a problem transmitting the alert signal , or the monitoring station was having a problem receiving it . Original plan . Early on , tests and activations were initiated in a similar way to CONELRAD tests . Primary stations would turn their transmitters off for five seconds , back on for five seconds , off for five seconds more , then would go back on air and transmit a 1000 Hz tone for 15 seconds to alert secondary stations . This quick off - and - on became known to broadcast engineers as the " EBS Stress Test " , as older transmitters would sometimes fail after the quick cycling on and off . This became unnecessary as broadcast technology advanced and the two - tone alarm was developed . Later test pattern . Beginning in 1976 , the old CONELRAD signaling method ( the " EBS Stress Test " ) was scrapped in favor of the following procedure : 1 . Normal programming was suspended , though tests were typically done during commercial breaks for continuity reasons . Television stations would transmit a video slide such as the one illustrated at the beginning of the article ; Numerous designs were available over the years . One of the following announcements was transmitted : Version 1 Version 2 2 . The Attention Signal was transmitted from the EBS encoder for 20 to 25 seconds . At the special request of the FCC , however , this step was occasionally ( though rarely ) skipped . In mid 1995 , a new rule was put in place that gave stations the option to transmit the attention signal for anywhere from 8 to 25 seconds . 3 . The announcement written below ( depending on the variation ) was transmitted . The first part read : Version 1 Version 2 There were a number of variations for the second half of the statement . During the system ' s early days , stations other than the designated primary station for an operational area were required to shut down in the event of an emergency ( reminiscent of the CONELRAD days ) , and the message was a variation of : By the early 1980s , it was easier for stations to record and relay messages from a primary station , and the risk of hostile bombers using broadcast signals to navigate lessened due to the development of ICBM s . As a result , the requirement to shut down during an activation of the system was dropped , and the message became : As the EBS was about to be replaced by its successor , the aforementioned Emergency Alert System , some stations used the following message : 4 . The test concluded with one of the following phrases : These variations were heard in different parts of the country throughout the years depending on FCC regulations at the time , local preferences , and whether the specific station performing the test was a primary EBS station or not . At least one version made explicit reference to an attack on the United States as being a possible scenario for EBS activation . The announcement text was mandated by the FCC . Stations had the option of either reading the test script live , or using recorded versions . WHEN radio in Syracuse , New York & WGR radio in Buffalo , New York both had a sung version of the most common script . There was also one done by Los Angeles - based Cheap Radio Thrills . The FCC declared it illegal to sing the test message , or read it as a joke . However , it was acceptable to read it in another language ( for example , French or Spanish ) , if a station broadcast in it . Copies of the warning message script had a note saying that it was acceptable to broadcast in any other language , so long as it was broadcast in English as well . Usually the post - test recorded announcement began with the phrase , " This has been a test of the Emergency Broadcast System . . . " , followed by the here - in - above stated recitations . Purpose of the test and cultural impact . The purpose of the test was to allow the FCC and broadcasters to verify that EBS tone transmitters and decoders were functioning properly . In addition to the weekly test , test activations of the entire system were conducted periodically for many years . These tests showed that about 80 % of broadcast outlets nationwide would carry emergency programming within a period of five minutes when the system was activated . The weekly broadcasts of the EBS attention signal and test script made it a significant part of the American cultural fabric of its time , and became the subject of a great number of jokes and skits , such as the sung versions of the test script in the late 1970s . In addition , many people have testified to being frightened by the test patterns and attention signal as children , and even more so by actual emergencies .