Retro Tech Tuesday: Know this sound? If so, you're over 30

Today, we take you back to hear a sound that is so hauntingly familiar to many of us, that all these years later, its like reuniting with an old friend. Of course it was an old friend that often led to frustration. I speak of course, of the phone modem dialing sequence. Show of hands: who could tell whether the connection would be successful based on the tone sequence? Enjoy!