Starting shortly before midnight Friday, emergency sirens all over the Dallas, Texas started blaring even though there was no emergency:
Rocky Vaz, director of Dallas' Office of Emergency Management, said that all 156 of the city's sirens were activated more than a dozen times.
Officials don't know who was responsible for the hacking, but Vaz said "with a good deal of confidence that this was someone outside our system" and in the Dallas area.
Deactivating the emergency alert system was the only way to stop the sirens:
The system remained shut down Saturday while crews safeguarded it from another hack. The city said the system should be restored Sunday or Monday — in time for thunderstorms that are expected to begin rolling through the area early next week.
[...] Dallas officials said they have begun working with the Federal Emergency Management Agency to add an alert system that would send messages to all cellphones in the area when there is an emergency.
(Score: 3, Interesting) by Geezer on Monday April 10 2017, @12:37PM
Back in the 1950's/1960's, the civil defense sirens were activated by a dedicated phone line and a simple relay. The ring tone voltage latched one relay, hangup let an old dashpot timer break the latch. Simple and effective, at least till the first warhead lands.
Anyone remember CONELRAD (AM 640 and 1240)? Jeez I miss the cold war.