A bit ago a semi-retired guy came back to help with some stuff including debugging serial ports. It was very cool to see him fiddle with the knobs and be like "oh those squiggles look good" "no that doesn't look right" etc. https://i.imgur.com/R5aEXbq.jpeg

Meanwhile total mystery to everyone else how to operate/interpret the machine but a lot of fun

One totally needs a 500 MHz oscilloscope to debug a kHz range serial port signal! :-)