I think you may have misunderstood. On my home security system, communication interruptions to a sensor are treated as a &quot;bad&quot; condition and alerts are sent with a comm warning. The system fails open.<p>With the xFinity system, it fails closed, meaning that when a sensor loses connection, the system assumes everything is OK until it hears from the sensor again. An alarm&#x2F;alert only occurs if a sensor affirmatively indicates a &quot;bad&quot; condition.