Exposing a Flaw In the Phone System https://www.youtube.com/watch?v=wVyu7NB7W6Y
https://en.wikipedia.org/wiki/Telefon_(1977_film) , https://www.youtube.com/watch?v=altSJMUmmHw
Sugarloaf - Don't_Call_Us,_We'll_Call_You (1974) https://www.youtube.com/watch?v=d6fFI8VQci8
https://en.wikipedia.org/wiki/Telephone_keypad , https://en.wikipedia.org/wiki/DTMF
https://en.wikipedia.org/wiki/Push-button_telephone
https://en.wikipedia.org/wiki/Rotary_dial
https://en.wikipedia.org/wiki/History_of_telecommunication#Telephone
https://en.wikipedia.org/wiki/History_of_telecommunication#Basic_electrical_signals
