the CD button turns into more of a band button (think the FM button that cycles between FM1 and FM2.) it cycles between the indash and the changer. the 1-6 disc selection buttons disappear from the mid while you're playing an indash cd. press cd, and the changer starts playing and the 1-6 keys show up. also, instead of CD 4-2 you see TR 2 (for track #2).