Fax Basics
https://faxauthority.com/how-a-fax-machine-works/#How_Faxes_Communicate

Images of Fax Devices
​https://www.google.com/search?rlz=1C1CHBF_enUS791US791&biw=1129&bih=920&tbm=isch&sxsrf=ACYBGNSGYhmmobR0_BqCxHRC3yOe5csdqw%3A1575768397052&sa=1&ei=TVHsXdjWApLH0PEPsfmVuA4&q=fax+machines&oq=fax+machines&gs_l=img.3..0l3j0i5i30l7.2996.8163..9602...0.0..0.57.638.13......0....1..gws-wiz-img.......35i39j0i67.5lnm75tcXYw&ved=0ahUKEwiYsbfc8qTmAhWSIzQIHbF8BecQ4dUDCAc&uact=5

Application Work-flow Charts