The Pioneer CDRB20 adapter allows you to add an auxiliary input to your Pioneer changer-controlling receiver and retain the use of your Pioneer CD changer. The CDRB20 accepts your IP-Bus changer cable and a patch cable from your auxiliary source (cassette, MP3, Minidisc, etc.) and allows your Pioneer receiver to play back either source. The auxiliary source must have a volume control or an output voltage of 1 volt or less.