Ademco 4120OEC Trouble
| NO AC | AC Power Failure |
| BAT | Panel Battery low |
| CHECK 01 – 08 | Zone trouble, possible bad Resistor |
| OC | Open Circuit, bad keypad wire |
| FC | Fail to Communicate |
| CC | Panel is being downloaded by Tech Support |
| Reset Smoke | 4-digit code + 1 (OFF) twice to turn off siren and reset smoke |
| (If this does NOT reset smoke detector set for service, smoke is bad) | |