Update: set off the 120dB siren in a client's attic at 6am and had to explain it to his sleeping wife
Was up in this guy's attic in Mesa last Tuesday running wire for a new panel and bumped the test button on a 120dB siren with my elbow. The thing screamed for a solid 20 seconds while I'm fighting to find the right wire to pull, and I could hear his wife yelling from downstairs asking if it was a fire. Turned out the panel keypad code the guy gave me was for the old system, so nothing I typed shut it off and I had to yank the battery backup to kill it. Client laughed it off but his wife made him stand in the driveway with me for 10 minutes after while I finished testing everything. Any of you keep a cheat sheet of master codes on hand for older panels or do you just pray the homeowner remembers?