Patent ID: 6499656
Filing Date: 2002-12-31
Classification: G06K

Abstract:
A method of identifying objects by an interrogator, comprising the steps of:transmitting an interrogation signal from the interrogator to the object; transmitting from each object to the interrogator an identification signal having predetermined indicator characteristics in response to the interrogation signal; receiving the identification signal from the object at the interrogator and substantially contemporaneously determining at the interrogator whether any identification signal has been individually and correctly received or not on the basic of the indicator characteristics; substantially contemporaneously transmitting from the interrogator a common re-transmit or interrupt signal to the objects in the event of the interrogator detecting a corrupted transmission state arising from any identification signal not being individually and correctly received; and independently ceasing signal transmission from an object if that object successfully completes its signal transmission without receiving an interrupt signal from the interrogator during such transmission.