Example patches for working with (analog) oscilloscopes in Max/MSP/Jitter.
Step 1: Find yourself an analog oscilloscope (Brüel & Kjær, Tektronix, etc.), 2-channel minimum with X/Y mode. Do not get a "vectorscope" unless you find one that accepts unmodulated DC input voltages (hint: most don't).
Step 2: Find yourself an audio interface with DC-coupled outputs. An interface with DC coupled outputs is what you need to drive a scope using these examples.
Step 3: Connect your computer to your audio interface and the outputs of the interface to the inputs of the oscilloscope. Most scopes use BNC / Coaxial inputs, so you might need an adaptor or a funky cable. Remember to select your audio interface in the Audio Settings... in Max.
Step 4: Have fun.