Inventory protection system
An inventory protection system has a plurality of cable segments with connectors on the ends thereof. The connectors permit pairs of cable segments to be releasably mechanically and electrically connectable to one another to form a continuous cable loop. A circuit connected to the cable loop periodically generates a test signal in the cable loop and checks to see if the test signal is able to travel all the way around the cable loop. The circuit generates an alarm signal if the test signal cannot travel all the way around the cable loop.
1. An inventory protection system, comprising:
an electrical circuit including:
a) a test pulse generator having an output;
b) a comparison device having first and second inputs and an output;
c) an electrical connection from the output of the test pulse generator to the first input of the comparison device; and
d) a reporting unit connected to the output of the comparison device for generating an alarm signal when the first and second inputs of the comparison device are not the same;
a first cable segment having one end attached to a male connector and the other end electrically connected to one of the test pulse generator output and the comparison device's second input;
a second cable segment having one end attached to a female connector and the other end electrically connected to the other of the test pulse generator output and the comparison device's second input;
the male and female connectors of each cable segment being releasably mechanically and electrically connectable to female and male connectors, respectively, of the other cable segment to form a continuous cable loop between the test pulse generator output and the comparison device's second input.
2. The structure of claim 1 further comprising at least one double-ended cable segment having one end attached to a male connector and the other end attached to a female connector, the double-ended cable segment's male and female connectors being mechanically and electrically connectable to the female and male connectors, respectively, of the first and second cable segments to form a continuous cable loop between the test pulse generator output and the comparison device's second input.
3. The structure of claim 1 wherein the other end of the first cable segment is hard wired to one of the test pulse generator output and the comparison device's second input.
4. The structure of claim 1 wherein the other end of the second cable segment is hard wired to the other of the test pulse generator output and the comparison device's second input.
5. The structure of claim 1 wherein the test pulse generator, the comparison device and the electrical connection from the output of the test pulse generator to the first input of the comparison device are mounted on a sensor circuit board.
6. The structure of claim 1 wherein the reporting unit for generating an alarm signal is mounted on a reporting unit circuit board.
7. The structure of claim 1 wherein the reporting unit includes a transmitter for wireless communication with a remote base station.
8. The structure of claim 1 wherein the electrical circuit further comprises a capacitor connected to the output of the comparison device.
9. The structure of claim 1 wherein the comparison device is an exclusive OR gate.
10. The structure of claim 1 wherein the electrical circuit is battery powered.
11. An electrical circuit for an inventory protection system, the circuit comprising:
a test pulse generator having an output;
a comparison device having first and second inputs and an output;
an electrical connection from the output of the test pulse generator to the first input of the comparison device;
a reporting unit connected to the output of the comparison device for generating an alarm signal when the first and second inputs of the comparison device are not the same; and
a plurality of cable segments having connectors on the ends thereof to permit pairs of cable segments to be releasably mechanically and electrically connectable to one another to form a continuous cable loop, the ends of the cable loop being connected to the output of the test pulse generator and the second input of the comparison device.
12. The structure of claim 11 wherein the test pulse generator, the comparison device and the electrical connection from the output of the test pulse generator to the first input of the comparison device are mounted on a sensor circuit board.
13. The structure of claim 11 wherein the reporting unit for generating an alarm signal is mounted on a reporting unit circuit board.
14. The structure of claim 11 wherein the reporting unit includes a transmitter for wireless communication with a remote base station.
15. The structure of claim 11 wherein the electrical circuit further comprises a capacitor connected to the output of the comparison device.
16. The structure of claim 11 wherein the comparison device is an exclusive OR gate.
17. The structure of claim 11 wherein the electrical circuit is battery powered.
18. A method of protecting inventory, comprising the steps of:
providing an electrical circuit that generates a periodic test pulse on a test pulse generator output;
connecting said test pulse generator output to a first input of a comparison device having first and second inputs and an output;
connecting a reporting unit to the output of the comparison device and generating an alarm signal when the first and second inputs of the comparison device are not the same; and
looping a plurality of cable segments having connectors on the ends thereof through the inventory items and connecting the cable segments to one another to form a continuous cable loop, the ends of the cable loop being connected to the output of the test pulse generator and the second input of the comparison device.
19. The method of claim 18 wherein the reporting unit includes a transmitter further including the step of wirelessly communicating the alarm signal to a remote base station.
20. The method of claim 18 further comprising the step of connecting a capacitor to the output of the comparison device.