Research: Artifacts in the signals through the Casio 3500 INI (547 00866) Answering machine

Today was another usual day, I was cleaning up mess and making things more organized. As a simplistic work place = less confusion. That’s when i came across this old (working condition) casio answering machine! The first thought in my mind was, “Why not pass an audio signal through the tape and see what we get! So, I’ve ripped it apart and trying to figure out the schematics of the circuity which is hard to find on the internet as its really old! What i intend to do with this... Read the Rest →