There's a audio 3.5mm to pigtail cable on sell at Adafruit: https://www.adafruit.com/product/1700
It looks like what I need as I could connect one side to an old phone, play some music and the loose wires to a breadboard\oscilloscope etc.
But what I don't understand is why it has 3 wires coming out of it and not just 2?
One wire is for ground - check Another should be for signal I believe and that's it.
But it has 3, and it says "Ground ring is black, middle ring is white and tip is red."
Why are there white and red and just one or the other? If I want the audio signal w/o caring if it's stereo, can I just pick say the red one and ignore the white one (or vice versa)?
Thanks kindly for your help..