Abstract: An inventory monitoring system (10) is provided, which includes a number of merchandise detectors (12) that each include a number of sensors that are configured to detect the presence or absence of products in a predetermined merchandise position, a position on a shelf in a retail space, and to emit a detect signal confirming such presence or absence. Each of the merchandise detectors (12) also includes a rear unit (28) with a transmitter that is connected to the sensor and that transmits the detect signal. The system (10) includes one or more gateway device (36,40) that receives the detect signals from the merchandise detectors (12) and compiles a merchandise data signal from the detect signals, and transmits it a computer (42) to be used in monitoring and managing inventory.