What was found
ETOPS SIGNIFCANT SYSTEM: CABIN ALT WARNING SOUNDED WHILE CLIMBING OUT OF FL250. CABIN ALT WAS APPROX 13,000FT PUT PRESSURIZATION MODE CONTROL PANEL TO MANUAL AND OUT FLOW VALVE TO CLOSE AND STARTED A DESCENT AT FL200 CABIN ALT WAS AT 9000 AND STOPPED THE DESCENT. CABIN ALT SLOWLY RETURNED TO NORMAL FOR FL200 AND CONTINUED FLIGHT TO DESTINATION. PERFORMED BITE CHECK ON DPCU 1 & 2 SYSTEM OK NO FAULTS FOUND AT THIS TIME IAW FIM 21-31 TASK 801.