AFAIK, there were multiple patterns of sound that the sirens can generate, but it became confusing to keep them straight. The patterns were published in the ph

AFAIK, there were multiple patterns of sound that the sirens can generate, but it became confusing to keep them straight. The patterns were published in the phone books, so the phone book's deprecation didn't help keep things going. And so, the sirens' use got simplified, with the side effect of "oh crap, we no longer have a way to tell people about different emergencies". I hope the use of the sirens to indicate more than one thing is brought back.