Specific Area Message Encoding

Last updated

Specific Area Message Encoding (SAME) is a protocol used for framing and classification of broadcasting emergency warning messages. It was developed by the United States National Weather Service for use on its NOAA Weather Radio (NWR) network, and was later adopted by the Federal Communications Commission for the Emergency Alert System, then subsequently by Environment Canada for use on its Weatheradio Canada service. It is also used to set off receivers in Mexico City and surrounding areas as part of the Mexican Seismic Alert System (SASMEX).

Contents

History

From the 1960s to the 1980s, a special feature of the NOAA Weather Radio (NWR) system was the transmission of a single 1050 Hz attention tone prior to the broadcast of any message alerting the general public of significant weather events. This became known as the Warning Alarm Tone (WAT). Although it served NWR well, there were many drawbacks. Without staff at media facilities to manually evaluate the need to rebroadcast an NWR message using the Emergency Broadcast System (EBS), automatic rebroadcasting of all messages preceded by just the WAT was unacceptable and impractical. Even if stations and others with the need were willing to allow for this type of automatic capture, assuming the events for activation were critical, there was no way for automated equipment at the station to know when the message was complete and restore it back to normal operation.

SAME had its beginnings in the early 1980s when NOAA's National Weather Service (NWS) began experimenting with system using analog tones in a dual-tone multi-frequency (DTMF) format to transmit data with radio broadcasts. [1] In 1985, the NWS forecast offices began experimenting with placing special digital codes at the beginning and end of every message concerning life- or property-threatening weather conditions targeting a specific area. The intent of what became SAME was to ultimately transmit a code with the initial broadcast of all NWR messages. However, the roll-out moved slowly until 1995, when the U.S. Government provided the budget needed to develop the SAME technology across the entire radio network. Nationwide implementation occurred in 1997, when the Federal Communications Commission (FCC) adopted the SAME standard as part of its new Emergency Alert System (EAS). [2] In 2003, NOAA established a SAME technology standard for weather radio receivers.

The SAME technique was later adopted by the U.S. Federal Communications Commission (FCC) in 1997 [3] for use in the EAS as well as by Environment Canada [4] for its Weatheradio Canada service in 2004. Much like the original EBS dual-tone Attention Signal , this produces a distinct sound (the SAME header ) which is easily recognized by most individuals due to its use in weekly and monthly broadcast tests, as well as weather alert messages. During the said events, viewers and/or listeners will hear these digital codes in the form of buzzes, chirps, and clicking sounds (colloquially known as "duck farts" by broadcast engineers) [5] just before the attention signal is sent out and at the conclusion of the voice message. [6]

Format of digital parts

In the SAME system, messages are constructed in four parts, the first and last of which are digital and the middle two are audio. The digital sections of a SAME message are AFSK data bursts, with individual bits lasting 1920  μs (1.92  ms) each, giving a bit rate of 52056  bits per second. A mark bit is four complete cycles of a sine wave, translating to a mark frequency of 208313  Hz, and a space bit is three complete sine wave cycles, making the space frequency 1562.5 Hz.

The data is sent isochronously and encoded in 8-bit bytes with the most-significant bit of each ASCII byte set to zero. The least-significant bit of each byte is transmitted first, including the preamble. The data stream is bit and byte synchronized on the preamble. [7]

Since there is no error correction, the digital part of a SAME message is transmitted three times, so that decoders can pick "best two out of three" for each byte, thereby eliminating most errors which can cause an activation to fail.[ citation needed ]

Header format

The text of the header code is a fixed format:

<Preamble>ZCZC-ORG-EEE-PSSCCC+TTTT-JJJHHMM-LLLLLLLL-

This is broken down as follows:

1. A preamble of binary 10101011 (0xAB in hex) repeated sixteen times, used for "receiver calibration" (i.e., clock synchronization), then the letters ZCZC as an attention to the decoder (a message activation method inherited from NAVTEX).

2. ORG — Originator code; programmed per unit when put into operation [8]

3. EEE — Event code; programmed at time of event

4. PSSCCC — Location codes (up to 31 location codes per message), each beginning with a dash character; programmed at time of event

5. TTTT — Purge time of the alert event (from exact time of issue)

The National Weather Service is changing the maximum purge time for alerts on NOAA Weather Radio from 6 hours to 99.5 hours by summer 2023 to address long duration events purging before the event begins. [10]

6. JJJHHMM — Exact time of issue, in UTC, (without time zone adjustments).

7. LLLLLLLL — Eight-character station callsign identification, with "/" used instead of "–" (such as the first eight letters of a cable headend's location, WABC/FM for WABC-FM, KLOX/NWS for a weather radio station programmed from Los Angeles, or EC/GC/CA for a Weatheradio Canada station).

Each field of the header code is terminated by a dash character, including the station ID at the end; individual PSSCCC location numbers are also separated by dashes, with a plus (+) separating the last location from the purge time that follows it.

Full message format

An EAS message contains these elements, in this transmitted sequence:

  1. Header.
  2. Attention signal — Sent if any message is included (normally sent with all messages except RWT on broadcast radio/TV); must be at least eight seconds long. (On weather radio in Canada the 1050 Hz tone is only used with three event codes: RMT, SVR & TOR[ citation needed ])
  3. Message — An audio message. The FCC permits encoded video or text in lieu of an audio message, but neither are implemented in practice. [11]
  4. Tail — (Preamble) NNNN (EOM).

There is one second of blank audio between each section, and before and after each message. For those used to packet communications systems where each packet has a checksum, note that there is no checksum used in the message format. The header and EOM are transmitted 3 times, [12] and the receiver is obliged to implement columnar parity correction.

The combined tones date back to 1976[ citation needed ] when they were made part of the Emergency Broadcast System, the EAS' predecessor.

Event codes

There are roughly 80 different event codes that are used in EAS. These codes are defined federally by the FCC for use in the EAS system and publicly by the Consumer Electronics Association (CEA) standard [13] for SAME protocol weather radio receiver decoder units.

All but the first six of these used to be optional and could be programmed into encoder/decoder units at the request of the broadcaster. However, a July 12, 2007, memo by the FCC now requires mandatory participation in state and local level EAS by broadcasters. Furthermore, the creation and evolution of a voluntary standard by the CEA in December 2003 has provided participating manufacturers of weather radio receivers a single definitive reference to use when designing and programming receivers. In addition, some receiver manufacturers have added an additional layer as to whether or not an event code can be user-suppressed (e.g., a Hurricane Warning in a Midwest US State) or will never be allowed to be suppressed (e.g., Nuclear Power Plant Warning).

Key for event code tables
USA type keyCAN/MEX type keyEvent level key
MMandatory codeABAdministrative bulletinADVAdvisory
O1Original optional codeCICurrently implementedWCHWatch
O22002 optional code [14] [15] RTRequired testWRNWarning
O32017 optional code [16] FIFor future implementationTESTTest
NINot implementedNINot implemented
TSTesting for Implementation
Event codes in use:
The following event codes have been implemented by agencies in the United States and/or Canada, and CIRES A.C. in Mexico.
Event CodeU.S. TypeCAN. TypeMEX. TypeEvent DescriptionEvent Level
ADRO1ABNIAdministrative MessageADV
AVAO2FINI Avalanche WatchWCH
AVWO2FINIAvalanche WarningWRN
BLUO3NINI Blue Alert WRN
BZWO1CINI Blizzard Warning WRN
CAEO2FINI Child Abduction Emergency ADV
CDWO2FINI Civil Danger Warning WRN
CEMO1FINI Civil Emergency Message WRN
CFAO2FINI Coastal Flood WatchWCH
CFWO2FINI Coastal Flood Warning WRN
DMOO1ABNIPractice/Demo WarningTEST
DSWO2CINI Dust Storm Warning WRN
EANMFINI National Emergency Message (Formerly known as "Emergency Action Notification", and is a national-level EAS activation. If it's ever used, it will be seen on all broadcast stations at the same time across the country, to carry a live Presidential message.)WRN
EATNIFINI Emergency Action Termination (No longer used after 2012. It was NOT used to terminate the Emergency Action Notification test of 2011.)ADV
EQWO2FICI Earthquake Warning WRN
EVIO1FINI Evacuation Immediate WRN
EWWO3NINI Extreme Wind Warning WRN
FFAO1FINI Flash Flood Watch WCH
FFSO1FINI Flash Flood StatementADV
FFWO1FINI Flash Flood Warning WRN
FLAO1FINI Flood Watch WCH
FLSO1FINI Flood StatementADV
FLWO1FINI Flood Warning WRN
FRWO2FINI Fire Warning WRN
FSWNICINIFlash Freeze WarningWRN
FZWNICINIFreeze Warning (also known as a "Frost Warning" in Canada.)WRN
HLSO1FITS Hurricane Local StatementADV
HMWO2FINI Hazardous Materials WarningWRN
HUAO1CITS Hurricane Watch WCH
HUWO1CITS Hurricane Warning WRN
HWAO1FINI High Wind Watch WCH
HWWO1CINI High Wind Warning WRN
LAEO2FINI Local Area Emergency ADV
LEWO2FINI Law Enforcement Warning WRN
NATNIABNINational Audible TestTEST
NICMABNINational Information Center (Never used, but assumed to be a National Emergency Message follow-up. This code will be discontinued on December 12, 2023.[ citation needed ])ADV
NMNO2ABNINetwork Notification MessageADV
NPTMABNINationwide Test of the Emergency Alert System (formerly known as "National Periodic Test")TEST
NSTNIABNINational Silent TestTEST
NUWO2FINI Nuclear Power Plant WarningWRN
RHWO2FINI Radiological Hazard WarningWRN
RMTMRTNIRequired Monthly Test (These are required to contain headers, an attention signal, an audio message, and end of message tones.)TEST
RWTMRTCIRequired Weekly Test (These only require headers and end of message tones, but an attention signal and/or audio message are optional except for NOAA Weather Radio stations.)TEST
SMWO2TSNI Special Marine Warning WRN
SPSO1FINI Special Weather Statement ADV
SPWO2FINI Shelter In-Place warningWRN
SQWO1CINI Snow Squall Warning WRN
SSAO3NINIStorm Surge WatchWCH
SSWO3NINIStorm Surge WarningWRN
SVAO1CINI Severe Thunderstorm Watch WCH
SVRO1CINI Severe Thunderstorm Warning WRN
SVSO1TSNISevere Weather Statement (U.S., CAN)ADV
TOAO1CINI Tornado Watch WCH
TOEO2FINI 911 Telephone Outage EmergencyADV
TORO1CINI Tornado Warning [17] WRN
TRAO2CINI Tropical Storm Watch WCH
TRWO2CINI Tropical Storm Warning WRN
TSAO1TSNI Tsunami WatchWCH
TSWO1TSNI Tsunami Warning WRN
VOWO2FICI Volcano Warning WRN
WSAO1CINI Winter Storm Watch WCH
WSWO1CINI Winter Storm Warning WRN
 ??AO2CINIUnrecognized WatchWCH
 ??EO2CINIUnrecognized EmergencyADV
 ??SO2CINIUnrecognized StatementADV
 ??WO2CINIUnrecognized WarningWRN

* Unrecognized Alerts are only seen on NOAA Weather Radios. This is typically due to poor reception, or for newly-implemented event codes, which an older radio may not recognize.

** While the CEA standard [13] lists the FZW event code as "Freeze Warning", Environment Canada refers to it [18] as a "Frost Warning". However, it will be displayed as a "Freeze Warning" on receivers that are compliant to the CEA standard.
Environment Canada additionally uses [18] the WSW event code to refer to any of the following weather conditions: Blowing Snow Warning, Freezing Drizzle Warning, Freezing Rain Warning, Snowfall Warning, Snow Squall Warning
*** The EQW and VOW event codes are used in Mexico as part of the Mexican Seismic Alert System (also known as SASMEX). EQW is referred as "Alerta Sísmica", while VOW is referred to as "Alerta Volcánica". [19] Other event codes are being tested, such as Hurricane Warning (HUW), Hurricane Watch (HUA) and Hurricane Statement (HLS). Required Weekly Tests (RWT) are conducted every three hours to make sure receivers are working properly. [20]
**** The FCC created the BLU code for Blue Alerts beginning on December 14, 2017. [21]
*****The FCC in 2012 modified protocol for national EAS activations. Emergency Action Notifications are now treated as any other EAS alert (except that it is mandatory to air), eliminating the need for Emergency Action Terminations, so the FCC removed it from operation. [22]
Internal use only:
Receiver decoders that comply to the CEA standard [13] will neither display the messages below, nor activate a warning tone if applicable. While the message will be stored in memory, it will not be displayed to the user. The FCC has also designated [14] these event codes as being for "internal use only", and not for display. Environment Canada lists [18] these messages as "Administrative Bulletins".
Event CodeU.S. TypeCAN. TypeEvent DescriptionEvent Level
TXBO2ABTransmitter Backup OnADV
TXFO2ABTransmitter Carrier OffADV
TXOO2ABTransmitter Carrier OnADV
TXPO2ABTransmitter Primary OnADV
The above events are only seen on NOAA Weather Radio if certain situations happen, such as a station losing power. In this case, the "TXB" or "Transmitter Backup On" code would be transmitted, following by beeping noises of multiple frequencies, finally followed by EOM tones. However, these tones are not typically transmitted over the air.
Future implementation:
The following codes are part of the CEA standard [13] for receiver decoders, but are not listed as being in use by any agencies in the United States. Environment Canada lists [18] these codes as being "for future implementation". None of these event codes are being implemented in Mexico, as Mexico's network is for seismic and volcanic alerts at this time.
Event CodeU.S. TypeCAN. TypeEvent DescriptionEvent Level
BHWNIFI Biological Hazard WarningWRN
BWWNIFI Boil Water Warning WRN
CHWNIFI Chemical Hazard WarningWRN
CWWNIFI Contaminated Water WarningWRN
DBANIFI Dam WatchWCH
DBWNIFI Dam Break WarningWRN
DEWNIFI Contagious Disease WarningWRN
EVANIFI Evacuation WatchWCH
FCWNIFI Food Contamination WarningWRN
IBWNIFI Iceberg WarningWRN
IFWNIFI Industrial Fire WarningWRN
LSWNIFI Landslide WarningWRN
POSNIFIPower Outage AdvisoryADV
WFANIFI Wild Fire WatchWCH
WFWNIFIWild Fire WarningWRN

The FCC established naming conventions for EAS event codes. The third letter of the code must be one of the following. [23]

Third letter of event codeCategoryDescription
WWarningAn event that alone poses a significant threat to public safety and/or property, probability of occurrence and location is high, and the onset time is relatively short.
AWatchMeets the classification of a warning, but either the onset time, probability of occurrence, or location is uncertain.
EEmergencyAn event that, by itself, would not kill, injure or do property damage, but indirectly may cause other things to happen that result in a hazard.
SStatementA message containing follow up information to a warning, watch, or emergency.

The exception to this convention is for "TOR" (tornado warning), "SVR" (severe thunderstorm warning), "EVI" (evacuation immediate), "EAN, EAT, NIC" (the EAS national activation codes), and "ADR" (administrative messages). [14]

On weather radio receivers

An example of a SAME alert weather radio receiver. SAMEWXRadio.jpg
An example of a SAME alert weather radio receiver.

There are many weather/all-hazards radio receivers that are equipped with the SAME alert feature, which allows users to program SAME/FIPS/CLC codes for their designated area or areas of their interest and/or concern rather than the entire broadcast area. (For example, a person living in Irving, Texas, would program a FIPS code for Dallas County. However, if there is a need to know of severe weather from the west and northwest ahead of time, the user would program additional FIPS codes for Denton and Tarrant Counties.)

On a more specialized receiver, a user has the option to eliminate any SAME alert codes that may not apply to their area such as a "Special Marine Warning" or a "Coastal Flood Warning". Once the SAME header is sent by NOAA/NWS and if it matches the desired code(s), the receivers then decode the event, scroll it on their display screens, and sound an alarm.

Receivers receive on one of the following National Weather Service network frequencies (in MHz): 162.400, 162.425, 162.450, 162.475, 162.500, 162.525, and 162.550. The signals are typically receivable up to 40 miles (80 km) from the transmitters. [24]

See also

Related Research Articles

<span class="mw-page-title-main">Emergency Broadcast System</span> Former United States emergency warning system

The Emergency Broadcast System (EBS), sometimes called the Emergency Action Notification System (EANS), was an emergency warning system used in the United States. It was the most commonly used, along with the Emergency Override system. It replaced the previous CONELRAD system and was used from 1963 to 1997, at which point it was replaced by the Emergency Alert System.

<span class="mw-page-title-main">CONELRAD</span> Former method of emergency broadcasting in the United States

CONELRAD was a method of emergency broadcasting to the public of the United States in the event of enemy attack during the Cold War. It was intended to allow continuous broadcast of civil defense information to the public using radio stations, while rapidly switching the transmitter stations to make the broadcasts unsuitable for Soviet bombers that might attempt to home in on the signals.

<span class="mw-page-title-main">Emergency Alert System</span> Method of emergency broadcasting in the United States

The Emergency Alert System (EAS) is a national warning system in the United States designed to allow authorized officials to broadcast emergency alerts and warning messages to the public via cable, satellite and broadcast television and both AM, FM and satellite radio. Informally, Emergency Alert System is sometimes conflated with its mobile phone counterpart Wireless Emergency Alerts (WEA), a different but related system. However, both the EAS and WEA, among other systems, are coordinated under the Integrated Public Alert and Warning System (IPAWS). The EAS, and more broadly IPAWS, allows federal, state, and local authorities to efficiently broadcast emergency alert and warning messages across multiple channels. The EAS became operational on January 1, 1997, after being approved by the Federal Communications Commission (FCC) in November 1994, replacing the Emergency Broadcast System (EBS), and largely supplanted Local Access Alert systems, though Local Access Alert systems are still used from time to time. Its main improvement over the EBS, and perhaps its most distinctive feature, is its application of a digitally encoded audio signal known as Specific Area Message Encoding (SAME), which is responsible for the characteristic "screeching" or "chirping" sounds at the start and end of each message. The first signal is the "header" which encodes, among other information, the alert type and locations, or the specific area that should receive the message. The last short burst marks the end-of-message. These signals are read by specialized encoder-decoder equipment. This design allows for automated station-to-station relay of alerts to only the area the alert was intended for.

Radio Data System (RDS) is a communications protocol standard for embedding small amounts of digital information in conventional FM radio broadcasts. RDS standardizes several types of information transmitted, including time, station identification and program information.

Multichannel Television Sound (MTS) is the method of encoding three additional audio channels into analog 4.5 MHz audio carriers on System M and System N. It was developed by the Broadcast Television Systems Committee, an industry group, and sometimes known as BTSC as a result.

<span class="mw-page-title-main">NOAA Weather Radio</span> Weather radio network in the United States

NOAA Weather Radio (NWR), also known as NOAA Weather Radio All Hazards, is an automated 24-hour network of VHF FM weather radio stations in the United States that broadcast weather information directly from a nearby National Weather Service office. The routine programming cycle includes local or regional weather forecasts, synopsis, climate summaries or zone/lake/coastal waters forecasts. During severe conditions the cycle is shortened into: hazardous weather outlooks, short-term forecasts, special weather statements or tropical weather summaries. It occasionally broadcasts other non-weather related events such as national security statements, natural disaster information, environmental and public safety statements, civil emergencies, fires, evacuation orders, and other hazards sourced from the Federal Communications Commission's (FCC) Emergency Alert System. NOAA Weather Radio uses automated broadcast technology that allows for the recycling of segments featured in one broadcast cycle into another and more regular updating of segments to each of the transmitters. It also speeds up the warning transmitting process.

<span class="mw-page-title-main">WWV (radio station)</span> U.S. government shortwave radio station

WWV is a shortwave radio station, located near Fort Collins, Colorado. It has broadcast a continuous time signal since 1945, and implements United States government frequency standards, with transmitters operating on 2.5, 5, 10, 15, and 20 MHz. WWV is operated by the U.S. National Institute of Standards and Technology (NIST), under the oversight of its Time and Frequency Division, which is part of NIST's Physical Measurement Laboratory based in Gaithersburg, Maryland.

The Global Maritime Distress and Safety System (GMDSS) is a worldwide system for automated emergency signal communication for ships at sea developed by the United Nations' International Maritime Organization (IMO) as part of the SOLAS Convention.

The Common Alerting Protocol (CAP) is an XML-based data format for exchanging public warnings and emergencies between alerting technologies. CAP allows a warning message to be consistently disseminated simultaneously over many warning systems to many applications, such as Google Public Alerts and Cell Broadcast. CAP increases warning effectiveness and simplifies the task of activating a warning for responsible officials.

<span class="mw-page-title-main">Emergency population warning</span> Warning issued by authorities to the public en masse

An emergency population warning is a method where by local, regional, or national authorities can contact members of the public to warn them of an impending emergency. These warnings may be necessary for a number of reasons, including:

<span class="mw-page-title-main">Weather radio</span> Specialized radio receiver for weather forecasts

A weather radio is a specialized radio receiver that is designed to receive a public broadcast service, typically from government-owned radio stations, dedicated to broadcasting weather forecasts and reports on a continual basis, with the routine weather reports being interrupted by emergency weather reports whenever needed. Weather radios are typically equipped with a standby alerting function—if the radio is muted or tuned to another band and a severe weather bulletin is transmitted, it can automatically sound an alarm and/or switch to a pre-tuned weather channel for emergency weather information. Weather radio services may also occasionally broadcast non-weather-related emergency information, such as in the event of a natural disaster, a child abduction alert, or a terrorist attack.

In a conventional, analog two-way radio system, a standard radio has noise squelch or carrier squelch, which allows a radio to receive all transmissions. Selective calling is used to address a subset of all two-way radios on a single radio frequency channel. Where more than one user is on the same channel, selective calling can address a subset of all receivers or can direct a call to a single radio. Selective calling features fit into two major categories—individual calling and group calling. Individual calls generally have longer time-constants: it takes more air-time to call an individual radio unit than to call a large group of radios.

Weatheradio Canada is a Canadian weather radio network owned and operated by Environment and Climate Change Canada's Meteorological Service of Canada division. Weatheradio Canada is headquartered in Montreal, Quebec and transmits in both official languages from 230 sites across Canada. Weatheradio Canada, as well as Environment Canada's weather telephone service Hello Weather, utilizes Nuance Communications text to speech voices. Starcaster Text to Speech, owned by STR-SpeechTech Ltd, was used from 1994 to 2021.

<span class="mw-page-title-main">Blizzard warning</span> Weather warning indicating blizzard conditions in the warned area

A blizzard warning is a hazardous weather statement issued by Weather Forecast Offices (WFO) of the National Weather Service (NWS) in the United States, which indicates heavy snowfall accompanied by sustained winds or frequent gusts of 35 mph (56 km/h) or greater are forecast to occur for a minimum of three hours. A blizzard tends to reduce visibilities to 14 mile (400 m) or less.

A forecast region is a unique geographical area for which individual weather reports are issued.

<span class="mw-page-title-main">National Emergency Message</span> National activation of the Emergency Alert System

A National Emergency Message, formerly known until 2022 as an Emergency Action Notification, is the national activation of the Emergency Alert System (EAS) used to alert the residents of the United States of a national or global emergency such as a nuclear war or any other mass casualty situation. This alert can only be activated by the president of the United States or a designated representative thereof, such as the vice president. The Emergency Broadcast System (EBS) also carried the Emergency Action Notification. No president has ever activated the alert aside from the 2011 national EAS test.

The Integrated Public Alert and Warning System (IPAWS) is an architecture that unifies the United States' Emergency Alert System, National Warning System, Wireless Emergency Alerts, and NOAA Weather Radio, under a single platform. IPAWS was designed to modernize these systems by enabling alerts to be aggregated over a network and distributed to the appropriate system for public dissemination.

Evacuation immediate is a warning issued through the Emergency Alert System (EAS) in the United States to notify the public of a mandatory evacuation due to a wildfire, approaching hurricane, or an imminent explosion due to a gas leak. It is typically issued by a local or state authority and is relayed by the National Weather Service. The warning can replace a Civil Emergency Message, Fire Warning, or other warnings when required.

<span class="mw-page-title-main">Emergency override system</span>

The Local Access Alert is a warning system designed to warn radio, television stations, cable television broadcast feeds or satellite signals of impending dangers, such as tornadoes, flash flooding and other civil emergencies. The system was largely replaced by the Emergency Alert System "[1]". in the United States, although it still exists in some areas which have not yet been upgraded, and is still used from time to time in areas that have upgraded to the EAS.

On February 11, 2013, the Emergency Alert System of five different television stations across the U.S. states of Montana, Michigan, Wisconsin, and New Mexico were hijacked, interrupting each television broadcast with a Local area emergency message warning viewers of a zombie apocalypse. The message was subsequently declared as a hoax by local authorities and was reported to be a result of hackers gaining access to the Emergency Alert System equipment of various television stations.

References

  1. Nelson, W.C. (2002). "American Warning Dissemination and NOAA Weather Radio".
  2. "The History of NOAA Weather Radio". Weather Radios Direct. Retrieved 13 May 2014.
  3. NOAA Weather Radio - Watches, Warnings and Tones/Alarms  National Weather Service in Philadelphia/Mount Holly (accessed October 1, 2009)
  4. http://www.ec.gc.ca/media_archive/press/2004/040107_b_e.htm  – The Green Lane: (Backgrounder) – Weatheradio Network (accessed Dec. 5, 2011)
  5. "EAS Meeting Minutes". Archived from the original on 2011-07-19. Retrieved 2010-06-28.
  6. WRSAME – Weather Radio Specific Area Message Encoder Archived 2013-04-15 at archive.today   Metro Skywarn (accessed August 20, 2009)
  7. http://www.nws.noaa.gov/directives/sym/pd01017012curr.pdf [ bare URL PDF ]
  8. 47CFR11.31(d)
  9. "EAS protocol".
  10. "Service Change Notice 23-03" (PDF). January 10, 2023.
  11. Wood, Tom; Price, Harold, eds. (May 14, 2010). ECIG Recommendations For a CAP EAS Implementation Guide (PDF) (Report) (Version 1.0 ed.). EAS CAP Industry Group, EAS-CAP Implementation Guide Subcommittee (published May 17, 2010). pp. 8–9. Archived (PDF) from the original on March 2, 2022. Retrieved October 11, 2022. The FCC specifies that the message portion may be audio, video, or text. In practice, neither text nor video is actually embedded into the audio signal. Video and text accompany video broadcasts of EAS alert audio, but these elements are not part of the audio encoding of EAS, and are not propagated through the "daisy chain" architecture of EAS decoding receivers.
  12. C. Hodan (October 3, 2011). National Weather Service Instruction 10-1712 (PDF) (Report). National Oceanic & Atmospheric Administration. p. A-1. Retrieved August 11, 2021.
  13. 1 2 3 4 Consumer Electronics Association (CEA) Technology Standard "CEA-2009-B (ANSI)", November 2010, accessed January 11, 2014.
  14. 1 2 3 "Federal Communications Commission Report and Order" (PDF). February 22, 2002. Retrieved September 22, 2012.
  15. "Electronic Code of Federal Regulations". Archived from the original on 2011-10-18. Retrieved 2011-04-16.
  16. "Federal Communications Commission Report and Order" (PDF). July 11, 2016. Retrieved August 30, 2017.
  17. The National Weather Service additionally uses the TOR event code to refer to an Extreme Wind Warning. See http://www.nws.noaa.gov/os/vtec/pdfs/EWWInstructions.pdf
  18. 1 2 3 4 Environment Canada – Weather and Meteorology "SAME Event Codes"
  19. Archived at Ghostarchive and the Wayback Machine : "Como Funciona el SARMEX". YouTube .
  20. Archived at Ghostarchive and the Wayback Machine : "Alerta sismica en Puebla, frecuencia 162.475". YouTube .
  21. "Blue Alert EAS Event Code". January 18, 2018. Retrieved February 1, 2019.
  22. "Federal Communications Commission Fifth Report and Order" (PDF). 10 January 2012. Retrieved 15 July 2021.
  23. National Weather Service , accessed September 22, 2012.
  24. NWR Specific Area Message Encoding (SAME), https://www.weather.gov/nwr/nwrsame
  25. "Cyclone Weather Alert for Texas Longhorns Fans". Youtube. Archived from the original on 2021-12-12. Retrieved 2020-01-08.
  26. "Knowing: Trailer #2". IMDb. Retrieved 2020-01-08.
  27. "MMK License LLC Agrees to Settle EAS Investigation". Federal Communications Commission. 2015-12-11. Retrieved 2020-01-08.
  28. Eggerton, John (November 5, 2013). "FCC Proposes Fining TBS $25,000 Over 'Conan' Promo". Broadcasting & Cable . Retrieved 2020-01-08.
  29. "Impractical Jokers - Sal's Virtual Reality Hell (Punishment) | truTV" via www.youtube.com.