Scott, The PSR 2000's Mic/Line input is "Balanced", ie., a 'Stereo' input. The Line input can be used with an external device, eg., portable CD/MP3 Player that has a Line Out. Run it into the PSR 2000's Line In and you have a Stereo signal to the PSR 2000's speakers.

Eddie, I use a "Balanced" 1/4" Mic Cable Jack that I run into the PSR 2000's Mic/Line In and it works flawlessly. So a 1/4" Stereo "Balanced" Mic Cable WILL work as evidenced by the fact that MINE works.

Best regards,
Mike

PS: I had the same concern about whether the PSR 2000's Mic/Line input was Stereo or Mono so I called Yamaha and they said it was definitely a "Balanced", ie. "Stereo" input connection. Now whether Yamaha Tech support gave me a correct answer or not is maybe up to Steve Deming to clarify for sure but that is what they told me when I called about a year or so ago. Regardless though, my "Balanced" Mic Cable still works flawlessly.

Best regards,
Mike