EAS Protocol
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3/11/97 7
EAS activations (tests or alerts) will consist of up to four elements: A header code An attention signal An aural message An end of message code
All EAS activations will include a header code data burst. The header code will be sent three times, with a one-second pause after each transmission, to ensure proper reception by EAS decoders.
Following the header code, a two-tone attention signal may be used to alert listeners and viewers that an EAS activation has occurred and that an aural message will follow. The attention signal should be used if, and only if, an aural message will be included as part of the alert.
An aural message would follow the attention signal. Use of the two-tone attention signal and an aural message will be determined by the originator of the alert; they are not required, but if one is used the other must accompany it.
All EAS activations will conclude with an end-of-message code data burst. The end-of- message code will be sent three times, with a one-second pause after each transmission, to ensure proper reception by EAS decoders.
Refer to the following diagram and descriptions for more information on each element.
|=----------------------------------HEADER CODE (approximately one second) ----------------------------<|
WHO WHAT WHERE WHEN WHO
|__________________________________________________________________________| \ \ \
COMPLETE EAS MESSAGE
* See the text regarding the use of the two - tone attention signal and the aural message
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EAS header codes consist of the following elements sent the in the following sequence:
[Preamble] ZCZC-ORG-EEE-PSSCCC+TTTT-JJJHHMM-LLLLLLLL
Preamble = Clears the system. The EAS encoder sends the preamble automatically.
ZCZC = An identifier. The identifier indicates the start of the ASCII code. It is sent automatically by the EAS encoder.
ORG = Originator Code. This code describes the type of entity originating an EAS activation. The user at initial setup programs it into an EAS encoder. The only originator codes are (11.31d):
EEE = Event Code. This code describes the type of event that has occurred and must be programmed into an encoder by the originator for each activation. (Note that in some cases, such as tests, the encoder may use a macro function which assigns the event code, making it seem like no event code was specified.)
The event codes listed in Tab 12 have been approved by the F.C.C. for EAS use in Oregon State [11.31e] only those codes approved by the F.C.C. may be used. Any agency which desires to use a code not on the list of approved event codes must submit the proposed code to the SECC for approval If the SECC agrees with the need for a new code the request will be sent to the FCC for approval by a consortium of the FCC, FEMA, and NWS officials. Once the code is approved it will be added to the Amaster list of event codes for Oregon State in Tab 12 and will be authorized for use. Eventually the FCC will update the Part 11 rules to include the new code.
3/11/97 9 PSSCCC = Location Code.
This code identifies the states, counties, and county areas that are affected by an EAS alert. The location codes have to be programmed by the alert originator each time an alert is sent. (Note that in some cases, such as tests, the encoder may use a macro function that assigns the location code, making it seem like no event code was specified.)
EAS location codes are based on FIPS (Federal Information Processing System) codes [11.31c]. Each state has been assigned a number and each county in each state has been assigned a number. The combination of the state number and the county number gives each county in the entire country a unique identification number. This makes up the “SSCCC” portion of the EAS location code. An additional digit has been added at the head of the FIPS code to make up the EAS location code. This digit, represented by the “P”, further defines the location described by the FIPS code, allowing each county to be broken down into nine smaller areas (see the chart on the next page). Boundaries of the smaller areas are determined by the State Division of Emergency Management in cooperation with local emergency management authorities.
0 = No Designation / entire county selected
5/15/2002 10 PSSCCC = Location Code. (Continued)
The FIPS code for the State of Oregon is 41. Here are some examples of EAS location codes or areas within Oregon:
Entire State = 041000 Clackamas County = 041005 Lane County = 041039
TTTT = Duration of the event.
This code defines how long the alert is expected to be in effect. The duration must be determined by the alert originator each time an alert is sent. Valid durations can be entered in 15 minute segments up to one hour and then in 30 minute segments beyond one hour. For example:
0015 = 15 minutes 0030 = 30 minutes 0045 = 45 minutes 0100 = 1 Hour 0230 = 2 Hours 30 minutes 0400 = 4 hours
JJJHHMM = Date (Julian) and time of day (UTC) the EAS was activated.
The encoder sends this automatically. The duration of the event is based on this code. The “JJJ” portion of the code represents the Julian date. The Julian date system numbers each day sequentially starting with 001 on January 1 each year.
Examples of Julian dates are:
The “HHMM” portion of the code represents the hours and minutes of the day using Coordinated Universal Time.
5/15/2002 11 LLLLLLLL =Encoder identifier code.
This code identifies the broadcaster, cable operator, Weather Service office, civil authority, or nuclear/industrial plant which operated the encoder that transmitted or retransmitted an activation. The information is programmed into the encoder at initial setup and is automatically added to the EAS header by the encoder.
“L-Code” identification must adhere to the following formats:
Broadcasters: Use station call letters as the L-Code identifier.
Examples:
Single station: KXXX (FM) Two stations: XXKYYY Three or more stations: The call letters of one of the stations is sufficient. The other stations sending the alert should keep a log of alerts sent as should the station which was identified in the L-Code portion of the header.
Cable Television:
Weather Service Offices: Use the letters “NWS” followed by the location abbreviation of the NWS office transmitting the EAS message:
Example: Portland :NWSKPQR Pendleton :NWSKPDT Boise: :NWSKBOI Medford: :NWSKMFR
3/11/97 12 Civil Authorities:
L-Codes for civil authorities will be constructed in the following manner:
Examples:
Clackamas County Sheriff ----------- CLACCOSH Portland Police Department --------- PORTCYPD
Military Groups:
Military groups should use the following as L-Code identifiers:
Army -------------- U.S.ARMY Navy -------------- U.S.NAVY Air Force --------- AIRFORCE Marine Corps --- U.S.M.C. Coast Guard ---- U.S.C.G.
Industry:
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An EAS activation may include a two-tone attention signal. The two-tone attention signal must consist of the fundamental frequencies of 853 and 960 Hz transmitted simultaneously [11.31a2] and must be from 8 to 25 seconds in duration [11.31c]. When used, the attention signal must follow the EAS header and must precede an aural message. It is not required for state and local alerts [11.51b].
An EAS activation may also include an aural message. EAS decoders are required to have the capability to record and store at least two minutes of audio information [11.33a3i]. The originator may supply an aural message of up to, but not more than, two minutes in length. The aural message will be transmitted following the attention signal. Transmission of the aural message is not required for state and local alerts [11.51b].
EAS end-of-message codes consist of the following elements sent in the following sequence:
[Preamble] NNNN
[Preamble] = Clears the system. The EAS encoder sends the preamble automatically.
NNNN = End of message.
This end of message character string comprised of four ASCII “N” characters. This indicates the end of the EAS message [11.31c].
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