Collier County, Florida, uses one of the most advanced 911 systems in the U.S., allowing callers to send texts and videos.

Your phone can help you contact emergency services—even when you’re off the grid. Here’s how to take advantage of it.

Calling 911 is meant to save lives. But the emergency service, and others like it, are also viewed as ripe targets for criminally minded cyber-attackers, according to a new federal assessment ...