Read Values of Headphone Jack

[Forkosh]

What I want to do is to be able to distinguish between tones emitting from a PC's headphone jack.

Now could I just do ADC on a PIC to read the values coming from the headphone wires (would I need an op amp)

I use the PIC16F616 and PICBASIC PRO

Thanks,
Eric

[skimask]

What I want to do is to be able to distinguish between tones emitting from a PC's headphone jack.
Now could I just do ADC on a PIC to read the values coming from the headphone wires (would I need an op amp)
I use the PIC16F616 and PICBASIC PRO
Thanks,
Eric

Short of using some FFT code (which may cost you some $$$), make a couple of tight bandpass filters using the op-amps, filter the output from those and feed that into the ADC pin.