US Patent 7295109 Monitoring system

The monitoring system has a monitoring apparatus and an access point that wirelessly communicates with the monitoring apparatus. The monitoring apparatus sends a wireless signal to the access point. The access point generates a Received Signal Strength Indicator of the received wireless signal. The access point checks for an entrance of an intruder between the monitoring apparatus and the access point based on the Received Signal Strength Indicator generated by the access point. The monitoring systems enables accurate detection of an entrance of an intruder using wireless communication technology.