In the mid-1990s I lived in a San Jose neighborhood with underground utilities. Sometimes water would get into the phone lines and cause short circuits. After

In the mid-1990s I lived in a San Jose neighborhood with underground utilities. Sometimes water would get into the phone lines and cause short circuits. After one bad rainstorm, our phone was unusable. If you picked up the handset you would just hear a bunch of clicks. Then two police officers knocked on the door. They said someone had called 911 from my number, they called back and no one answered, so they were required to come out and investigate. I told them no one had called 911 and we were fine. Then it dawned on me: the clicks! I invited them in so they could listen to the phone, and explained how old rotary dial phones work: by opening and closing the circuit once to dial a 1, twice for 2, etc. And the phone system still supported rotary dial phones. Sure enough, with random clicks all day, the phone circuit had just happened to detect nine clicks, pause, one click, pause, and one click.