Granted Patent B2

US 6,956,480 · App. 10/368,364 · Granted Oct 18, 2005

Abstract

Claims (31)

1. A communication unit including a device for preventing loss or theft of the unit, the device receiving and assessing an enabling signal comprising identity information from an external source, and controlling operation of the communication unit in dependence upon the assessment, the device measuring signal strength of the enabling signal and examining the identity information included in the enabling signal, triggering a first alarm if the enabling signal strength is below a first predetermined level and triggering a second alarm if the enabling signal strength is below a second predetermined level that is lower than the first predetermined level, with the alarms perceptibly indicating different alarm conditions, wherein the device determines whether the identity information correctly enables operation of the unit only if signal strength of the enabling signal is above the second predetermined level, and wherein the unit is not inoperable until the unit is enabled.

2. A communication unit according to claim 1 wherein:

the device comprises a radio frequency tag.

3. A communication unit according to claim 1 wherein:

the device is incorporated in a smart card.

4. A communication unit according to claim 1 wherein:

the first device is incorporated within a badge.

5. A communication unit according to claim 1 wherein:

the first device is incorporated in an item of jewelry.

6. A communication unit according to claim 1 wherein:

the first device is incorporated in an article of clothing.

7. A communication unit according to claim 1 wherein:

the first device is incorporated into an item of personal property.

8. A communication unit according to claim 7 wherein:

the communication unit is a mobile telephone.

9. A communication unit according to claim 7 wherein:

the communication unit is a computer.

10. A system for preventing loss of theft of communication unit, the system comprising:

a communication unit;

a first control device which transmits an enabling signal; and

a second control device which receives and assesses the enabling signal and controls operation of the communication unit in dependence upon the assessment; and wherein,

the second control device measures signal strength of the enabling signal and examines identity information included in the enabling signal, triggering a first alarm if the enabling signal strength is below a first predetermined level and triggering a second alarm if the enabling signal strength is below a second predetermined level that is lower than the first predetermined level, with the alarms perceptibly indicating different alarm conditions, and determining whether the identity information correctly enables operation of the communication unit only if signal strength of the enabling signal is above the second predetermined level, and wherein the communication unit is not inoperable until the communication unit is enabled.

11. A method of preventing loss or theft of a communication unit, the method comprising:

transmitting an enabling signal;

receiving and assessing the enabling signal; and

controlling operation of the communication unit in dependence upon the assessment; and

measuring signal strength of the enabling signal and examining identity information included in the enabling signal, triggering a first alarm if the enabling signal strength is below a first predetermined level and triggering a second alarm if the enabling signal strength is below a second predetermined level that is lower than the first predetermined level, with the alarms perceptibly indicating different alarm conditions, wherein a determination is made whether the identity information correctly enables operation of the communication unit only if signal strength of the enabling signal is above the second predetermined level, and wherein the communication unit is not inoperable until the communication unit is enabled.

12. A communication unit including a controller, the communication unit receiving and assessing an enabling signal from an external source and which controls operation thereof in dependence upon assessing the enabling signal to prevent loss or theft of the communication unit under control of the controller; and wherein

signal strength of the enabling signal is measured and identity information included in the enabling signal is examined, triggering a first alarm if the enabling signal strength is below a first predetermined level and triggering a second alarm if the enabling signal strength is below a second predetermined level that is lower than the first predetermined level, with the alarms perceptibly indicating different alarm conditions, wherein the controller determines whether the identity information correctly enables operation of the communication unit only if signal strength of the enabling signal is above the second predetermined level, and wherein the communication unit is not inoperable until the communication unit is enabled.

13. A communication unit including a controller, the communication unit receiving and assessing an enabling signal from an external source, the controller controlling operation of the communication unit in dependence upon an assessment of the enabling signal to prevent loss or theft, the communication unit under control of the controller which

measures signal strength of the enabling signal and examines identity information included in the enabling signal, triggers a first alarm if the enabling signal strength is below a first predetermined level and triggers a second alarm if the enabling signal strength is below a second predetermined level that is lower than the first predetermined level, with the alarms perceptibly indicating different alarm conditions, wherein the controller determines whether the identity information correctly enables operation of the communication unit only if signal strength of the enabling signal is above the second predetermined level, and wherein the communication unit is not inoperable until the communication unit is enabled.

Assignments (13)