[old-ager]

I did not know that! Wish I could go back and play with it.

I think there ws a secret number that would tell you the phone number you were calling from, and another one that would phone you back as a test.

I’ve wondered if there were any filters on pay phones to stop someone from playing back the coin chimes from a tape.

[Jamestown1630]

69. Now, I think it’s *69

[null and void]

ding, ding-ding, bong
nickel, dime, quarter

[T.B. Yoits]

I think there was a secret number that would tell you the phone number you were calling from...

Absolutely. I don't recall it but it was used on every job site before mobile phones. As a home or building was going up, the first contractor after the phone service was established would connect to a jack and call the number. He'd write the number on the wall so the other contractors could have their shops call the site.