This is kind of mind-bending. I had to read this blog twice to believe it.
In this post I’m describing a method which is widely used to Dump RAM and ROM images on Sharp PC-1500 and PC-1600 systems. This method is non-destructive and can be used on most Sharp PC ROMs and extension cards. It only requires a Sharp CE-150 extension, an audio cable, and a computer with a microphone input (i.e. sound card).