Your system may emit a three beep every 20 seconds or so while disarmed. There can be two causes:
- No phone numbers are programmed into the system. Solution: add a phone number.
- Line Cut is enabled but no phone line is plugged into the Out Line jack or there is no dial tone. Solution: plug a phone line with a dial tone into the Out Line jack or disable the Line Cut feature.
Keywords: three beeps, 3 beeps