As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT FL270, EN ROUTE, THE CABIN ALTITUDE WARNING CAME ON & ALL THE MASKS IN THE CABIN DEPLOYED. THE CREW & PASSENGERS DONNED THEIR OXYGEN MASKS. THE CREW DECLARED AN EMERGENCY & DIVERTED. R & R CABIN PRESSURE ACQUISITION MODULE IAW AMM. PN ON: 1027SB04C03, SN ON 1284A; PN OFF: 1027SB0404C03, SN OFF 9712687A.