Phone Number 77-106

I remember that Anna's phone number in the early 50's was
77-106
I looked in an old phone book from the 40's, and this was also the number for 509 Parade, except it was written as
7-7106
Before we had a phone, my dad strung a wire between 505 and 501 for a buzzer. If Pat called me, he'd call Anna, and she'd press the buzzer 3 times, and I'd go over to Anna's to answer the phone. If Harry called Tommy, it was 4 buzzes, and if David called David, it was 5 buzzes.