When TV shows and movies need to use a phone number as part of the story, they typically use one that starts with 555. We spoke with an official historian at AT&T to find out why these three numbers ...

As soon as an actor in a movie or TV show starts rattling off a phone number, every viewer knows what the first three digits will be: 5-5-5. How did “555” become the convention for fake phone numbers, ...

Used in a variety of timer, pulse generation, and oscillator applications, the 555 was designed in 1971 by Hans Camenzind. A favorite for many engineers, the 555 is still in widespread use due to its ...