Responding to fears of an imminent Soviet nuclear attack, in 1951 Pres. Harry Truman set up a national system enabling the president to quickly notify the public of an impending national security threat via a cross-country relay chain of AM radio stations. It used characteristic blaring warning tones and became a precursor of the Emergency Alert System still in use today. “There are certain stations across every market that listen for those tones and then retransmit the alert to other stations in their market,” says John Lawson, an emergency alert expert who has advised the Federal Emergency Management Agency (FEMA) on its modern warning systems.
Public Television Leading the Way on Mobile Digital TV Emergency Alert System
The Public Broadcasting Service and LG Electronics are conducting a groundbreaking one-year pilot project of a next-generation broadcast Mobile Emergency Alert System (M-EAS). Co-funded by the Corporation for Public Broadcasting and LG, the pilot project is assessing the potential of public and commercial television stations using mobile digital television to broadcast rich-media emergency messages to the public.
Building on its long history of broadcasting innovation, public television is leading the way in the development and testing of M-EAS. In addition to serving as test markets, APTS members Vegas PBS (KLVX), WGBH (Boston), and Alabama Public Television stations WBIQ (Birmingham) and WAIQ (Montgomery) are providing video, audio, data and photo content for the project. Seattle commercial station KOMO-TV (Fisher Communications) also developed a compelling tsunami video alert simulation. (No CPB funding has gone to Fisher or KOMO-TV).
M-EAS has far-reaching public safety benefits. It can provide critical information – encrypted if necessary – to first responders who need to reserve other networks for two- way communications. For the general public, federal and state agencies can distribute messages instantly to millions of Americans with a single broadcast.
How M-EAS Works
- M-EAS uses terrestrial TV broadcasting rather than cellular network connectivity (which often become overloaded in times of emergencies).
- Both local M-EAS alerts and those originated from the President are formatted initially as text messages using the same U.S. Government-approved standard that the cellular industry will use to deliver short text alerts, which in turn is based on the international Common Alerting Protocol (CAP), also approved by the U.S.
- Additional rich media resource files from servers, the cloud and weather radar are integrated at the local broadcast station with the national, state or local alerts. These rich media resources will be added automatically by secure servers, as prescribed by the CAP standard.
- The M-EAS messages, which can include video, audio, text, maps and photos, are transmitted over-the-air using another open standard, North America’s ATSC Mobile DTV broadcast standard.
- Finally, the alerts are viewed and heard on Mobile DTV-equipped smartphones, tablets, and laptops with software that receives and displays the messages and their associated rich-media resources.Key Pilot Project Factoids
- Because M-EAS requires no additional bandwidth, it represents a “dual use” of existing transmitters and towers.
- The pilot project uses existing standards for implementation, including:
The U.S. broadcast standard for Mobile DTV, the A/153 MDTV standard,
adopted by the Advanced Television Systems Committee, and
The international Common Alerting Protocol (CAP), which specifies how
messages are structured, and the related Commercial Mobile Alert standard adopted by the cellular industry for text alerts.
- In addition to co-funding the project with CPB, LG Electronics and its Zenith R&D Lab developed prototype MDTV Android smartphones with M-EAS software.
- Harris Corporation and Roundbox are providing technical support at the local MDTV- enabled PBS stations involved in the pilot project.