What was found
ROC FLT 2516 THE CREW REPORTED WHILE DESCENDING THROUGH FL200 AURAL WARNING "CABIN" ACCOMPANIED BY INCREASE CABIN ALT AND DECREASE DELTA P ON EICAS, MANUAL WORKED FINE. A/C REL IAW MEL 21-30-00/1,CTA"C", CTL NUMBER 185425, C/W "M" PROCEDURES PER DDP. MAINTENANCE REPLACED THE DIGITAL CONTROLLER ON 1/15/2010 AND OPERATIONAL CHECKS WERE GOOD.