The interrupted ring signal was studious to attract study and population growth ringtones Samsung showed that an intermittent two tone ring was the easiest to hear. This had nothing to do with the coded ringing that was used on party line.
A phone only rings when a special "ringing signal" is sent to it. For regular telephones, the ringing signal is a 90-volt, 20-hertz, AC current generated by the switch to which the telephone is connected. For mobile phones, the ringing signal is a specific radio-frequency ringtones samsung signal.