What was found
DURING CRUISE WHILE AT FL 350, RECEIVED CAB PR SYS 1 AND 2 FAULT AND CABIN ALTITUDE CLIMBED TO 18.500 FEET. FOLLOWED COCKPIT OPERATING MANUAL PROCEDURES AND INITIATED EMERGENCY DESCENT. ALL OXYGEN MASKS AND OXYGEN GENERATORS DEPLOYED AND ACTIVATED PROPERLY. THE AIRCRAFT DIVERTED TO DTW AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED BOTH SYSTEM 1 AND SYSTEM 2 CABIN PRESSURE CONTROLLERS AND OPERATIONAL CHECK OK. REPACKED ALL OXYGEN MASKS IN THE LAVATORIES AND RESTORED THE OXYGEN SYSTEM IN THE CABIN. OPERATIONAL CHECK OK.