Recently I needed to build an audio breakout cable to connect an iPhone to an iPad. The idea was to run a noise/tone generator on one and run a spectrum analyzer on the other. I had a really hard time finding a straightforward solution online so I’m posting a very simple schematic here.

Technically you don’t need a TRRS (4-pole)connector for the receiving end. If you decide to use a TRS connector there then you’d just connect the resistor to the single “ring” pole.

audio_schematic

If you don’t need to put any circuitry between the devices then you should just buy two TRRS pigtails and wire them together for a simpler connection.

Audio breakout cable for iPhones and iPads