Recording Audio from External Source - Note 7, 4 or 2

[wrl-2]

I want to use my Note 2 (or Note 4 or 7) to record audio from a device which outputs mono audio from either Headphone or an External Speaker socket (both these sockets are standard 3.5mm headphone jack [mono]). I believe the connections for these sockets are Ground and Audio. I want to make a cable that connects from the 3.5mm 2-pin to a 4-pin plug to record audio from the device. I believe all of the Galaxy Notes use a standard 4-pin TRRS socket. Does anyone know which pins to use for Audio?