Activation
The initiation of the Emergency Alert System by transmission of the Emergency
Alert System codes
ASCII
A standard set of text characters with numerical equivalents
Attention Signal
Eight seconds of two tones (853 and 960 Hz) used as an audio alert
Audio Frequency Shift Keying (AFSK)
A digital modulation technique that uses two shifting audio frequencies to
transmit binary data
Authenticator Word Lists
A list of words that federal officials send prior to official Emergency Alert
System national activation; used to substantiate the information being sent
Authorization Letter
The official authorization letter, given by the FCC, for a broadcast station to go
off the air during a national level activation of the Emergency Alert System
Automatic Interruption
The automatic encoding and transmission of Emergency Alert System codes for
preselected events
Baud Rate
The speed of data transmitted, equal to number of elements sent per second
(equal to bits per second if a bit is the element)
Bit Rate
The speed of binary data transmitted, equal to the number of digital bits sent per
second
Certification
An equipment authorization issued by the FCC based on representations and test
data submitted by the applicant for equipment designated to be operated without
individual license under Parts 15 and 18 of the rules
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Class D FM station
A station whose output power is 10 Watts or less
Direct Broadcast Satellite (DBS)
A service intended to deliver satellite signals directly to consumers using small,
relatively inexpensive receive stations
Decoder (Emergency Alert System)
An electronic device used by Emergency Alert System participants to receive
alerts and to translate the Emergency Alert System codes into a visual message
Decoder (Two-Tone)
An electronic device that alerts operators to the reception of the two-tone signal
Emergency Action Notification (EAN)
The message for national Emergency Alert System activation
Emergency Action Termination (EAT)
The message for national Emergency Alert System termination
Encoder (Emergency Alert System)
A electronic device used by Emergency Alert System participants to originate
Emergency Alert System alerts by creating the Emergency Alert System codes
for transmission to other participants and the public
Encoder (Two-Tone)
A electronic device that produces the two-tone signal
EOM (end-of-message) Code
In ASCII form 'NNNN', this burst of data, sent three times, signifies the end of an
Emergency Alert System message and Emergency Alert System activation
Event Codes
A three character ASCII code in the Emergency Alert System headers that
denotes the type or cause of emergency event
Federal Emergency Management Agency (FEMA)
One of the three federal agencies that administer the Emergency Alert System
FIPS(Federal Information Processing System) Number
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A five character ASCII code in the Emergency Alert System headers that
represent those counties affected by an Emergency Alert System activation, as
defined by the Federal Information Processing System that assigns each state and
territory with their respective counties a five digit number
Header Code
A single string of intelligent digital Emergency Alert System ASCII data that
includes the originator, event, location, time period, and other basic information
concerning an emergency; three header codes precede the voice warning message
Julian Calendar
A method of specifying the date by the number of days which have passed since
the first day of January in a year
Key Source
A source which is central to the dissemination of emergency alerts and
information, such as National Primary, State Primary, State Relay or Local
Primary broadcast stations or cable systems
Local Primary (LP)
A key source within an Emergency Alert System Local Area that is the primary
source of Emergency Alert System programming for that area
Location Code
An ASCII code in an Emergency Alert System header that specifies the location
of an emergency utilizing the five character Federal Information Processing
System (FIPS) code of a state and county, and a sixth character to designate nine
divisions of a county
Low Power Television (LPTV)
A low-power power television transmitting station which may originate original
programming from a local source
Mapbook
A list of broadcast stations and cable systems and their designation delineated by
state and local area for use by other stations to determine the best source of
Emergency Alert System monitoring; an FCC generated attachment to every state
plan
Mark Frequency
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The audio frequency of audio frequency shift keying (AFSK) modulation that
corresponds to a digital bit of one (1); the mark frequency of Emergency Alert
System codes is 6250/3 Hz, or approximately 2083.33 Hz
Monitoring Assignment
The off-air broadcast or cable sources of Emergency Alert System activations
and programming as given in the FCC Mapbook and the state plan
National Control Point Procedures
Those national Emergency Alert System procedures used only by national
networks and program suppliers
National Information Center (NIC)
A source of official federal government information
National Oceanic and Atmospheric Administration (NOAA)
One of the three federal agencies that participate in Emergency Alert System
National Periodic Test (NPT)
A test of National Primary Emergency Alert System sources
National Primary (NP)
A primary source of Presidential or other national Emergency Alert System
activations and programming, including broadcast stations involved with the PEP
system and EAN Networks
National Weather Service (NWS)
An operation of the National Oceanic and Atmospheric Administration (NOAA)
that is directly responsible for issuing local weather-related emergency alerts and
warnings in addition to day-to-day forecasts and other weather activities
National Oceanic and Atmospheric Administration Weather Radio (NWR)
A service of the National Weather Service that provides to a local area
continuous broadcasts of the latest weather information and any weather-related
emergency warnings using one of seven VHF radio channels
Non-participating National (NN)
An Emergency Alert System source (usually a broadcast station) that has elected
not to participate in the National-level Emergency Alert System and removes its
carrier from the air if a national-level activation occurs
Operating Handbook
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A document issued by the FCC that instructs broadcast station and cable
personnel of the actions they must take during an activation of Emergency Alert
System
Operator Interruption
The transmission of an Emergency Alert System activation which has been
manually initiated by broadcast station or cable system personnel
Originator Code
A three character ASCII code in an Emergency Alert System header which
denotes the source of an activation
Participating National (PN)
Broadcast stations, cable systems, or MDS stations which monitor primary
sources of Emergency Alert System programming and directly feed emergency
alerts to the public
Preselected Code
An Emergency Alert System event which the operator of Emergency Alert
System equipment has chosen to be automatically encoded and retransmitted
upon reception
Primary Entry Point (PEP)
Key broadcast stations throughout the U.S. which together can provide national
emergency information
Protocol
A standard set of guidelines by which digital information encoded and decoded,
including the common code structure, character set used, the sequence and timing
of codes, and modulation technique used for radio transmission
Program Priorities
The precedence of the information that must be transmitted during an Emergency
Alert System activation, namely national, local, and state activations in that order
Radio Broadcast Data System (RBDS)
A defined protocol for data that is transmitted on the 57 kHz subcarrier of FM
radio broadcast stations utilized mainly by consumer devices equipped to receive
it
Required Monthly Test (RMT)
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A coordinated monthly test of Emergency Alert System operations involving the
full receiving and transmission of Emergency Alert System codes, Attention
Signal, Emergency Alert System test programming, and Emergency Alert System
end-of-message (EOM) codes
Required Weekly Test (RWT)
An independent weekly test of Emergency Alert System equipment only
involving the decoding and encoding of Emergency Alert System header codes
and end-of-message (EOM) codes
RS232
A common interface standard which specifies the mechanical connection,
electrical signals, and the function of the signals carried across the interface
Space Frequency
The audio frequency of AFSK modulation that corresponds to a digital bit of zero
(0); the space frequency of Emergency Alert System codes is 6250/4 Hz, or
1562.5 Hz
State/Local Plan
A document that details monitoring assignments. actions to be taken in
emergency activations, and other guidance for broadcasters and cable personnel
in use of the Emergency Alert System
State Primary (SP)
A primary source of Emergency Alert System state programming which can
originate with a Governor or designated representative, such as a state’s
emergency operations officer
State Relay (SR)
An entity which receives and retransmits Emergency Alert System activations in
a State Relay Network to assist in bringing a state activation to all Emergency
Alert System Local Area of a state
State Relay Network
A system of facilities used to distribute State Emergency Alert System
activations and programming across a state
Subcarrier
An inaudible portion of the broadcast signal that is added to the program signal
of the FM or TV sound and these can include the FM 57 kHz, 67 kHz, 69 kHz,
and 92 kHz and the TV Subsidiary Communications Services
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Subsidiary Communications Services
A subcarrier of television and FM stations providing a second audio
programming source
UTC
Coordinated Universal Time, the world-wide common time standard that is used
in Emergency Alert System headers for time stamp
Valid Code
An Emergency Alert System header which has been matched bit-for-bit with one
of two other received headers thereby checked for validity
WRSAME
Weather Radio Specific Area Message Encoder, a device used by National
Weather Service to broadcast WRSAME data on the National Weather Radio for
day-to-day forecasts and weather related emergency announcements
This section of our technical library presents information and documentation relating to