Patent ID: 8384543

Claim:
A security system for monitoring theft of a merchandise item placed on a merchandise rack at a shop, the security system comprising: a sensor attached to the merchandise item; a slave unit attached to the merchandise rack and connected to one or a plurality of said sensors via a wire; and a master unit that monitors theft of the merchandise item by wirelessly receiving a signal using a first frequency band from one or a plurality of said slave units, said slave unit comprising: detection unit configured to detect one of detachment of said sensor from the merchandise item, detachment of said slave unit from the merchandise rack, and detachment of the wire from said slave unit so as to detect the theft of the merchandise item; slave-unit-side transmission unit that wirelessly transmits a signal using the first frequency band, configured to transmit, to said master unit, an alarm signal that instructs to start an alarm operation when said detection unit has detected the theft of the merchandise item; and slave-unit-side receiving unit that wirelessly receives a signal using a second frequency band representing a band different from the first frequency band, configured to receive an instruction from a remote controller that wirelessly transmits various kinds of signals using the second frequency band, and said master unit comprising: first master-unit-side receiving unit that wirelessly receives the signal using the first frequency band, configured to receive the alarm signal transmitted by said slave-unit-side transmission unit; second master-unit-side receiving unit that wirelessly receives the signal using the second frequency band, configured to receive the instruction from the remote controller; and master-unit-side alarm unit configured to start the alarm operation when said first master-unit-side receiving unit has received the alarm signal.