05 永远忘不了那一刻

And we again, we were captivated.

How could anybody do this?

And we thought it must be a hoax.

And we started looking through libraries, looking for the secret tones that would allow you to do this.

And it turned out that we were at Stanford Linear Accelerate Center one night, and way in vaults of their technical library, way down at the last bookshelf in the corner bottom rack, we found an AT&T Technical Journal that laid out the whole thing.

And that's another moment I'll never forget.

We saw this journal and we thought "My God! It's all real".

And so we set out to build a device to make these tones.

And the way it work was, you know when you make long distance call, you used to hear "dududududu" right in the background.

They were tones that sound like the touch tone you make on your phone, but with different frequencies so you can make them.