Abstract: Communications device identification methods, communications methods, wireless communications readers, wireless communications systems, and articles of manufacture are described. In one aspect, a communications device identification method includes providing identification information regarding a group of wireless identification devices within a wireless communications range of a reader, using the provided identification information, selecting one of a plurality of different search procedures for identifying unidentified ones of the wireless identification devices within the wireless communications range, and identifying at least some of the unidentified ones of the wireless identification devices using the selected one of the search procedures.

Abstract: A system and method of inventorying multiple objects utilizing a multi-level or a chained radio frequency identification system. The system includes a master tag and a plurality of upper level tags and lower level tags associated with respective objects. The upper and lower level tags communicate with each other and the master tag so that reading of the master tag reveals the presence and absence of upper and lower level tags. In the chained RF system, the upper and lower level tags communicate locally with each other in a manner so that more remote tags that are out of range of some of the upper and lower level tags have their information relayed through adjacent tags to the master tag and thence to a controller.

Abstract: A system and method of inventorying multiple objects utilizing a multi-level or a chained radio frequency identification system. The system includes a master tag and a plurality of upper level tags and lower level tags associated with respective objects. The upper and lower level tags communicate with each other and the master tag so that reading of the master tag reveals the presence and absence of upper and lower level tags. In the chained RF system, the upper and lower level tags communicate locally with each other in a manner so that more remote tags that are out of range of some of the upper and lower level tags have their information relayed through adjacent tags to the master tag and thence to a controller.

Abstract: A radio-frequency transponder device having an antenna circuit configured to receive radio-frequency signals and to return modulated radio-frequency signals via continuous wave backscatter, a modulation circuit coupled to the antenna circuit for generating the modulated radio-frequency signals, and a microprocessor coupled to the antenna circuit and the modulation circuit and configured to receive and extract operating power from the received radio-frequency signals and to monitor inputs on at least one input pin and to generate responsive signals to the modulation circuit for modulating the radio-frequency signals. The microprocessor can be configured to generate output signals on output pins to associated devices for controlling the operation thereof. Electrical energy can be extracted and stored in an optional electrical power storage device.

Abstract: A radio frequency (RF) communication system employs phase-modulated backscatter signals for RF communication from an RF tag to an interrogator. The interrogator transmits a continuous wave interrogation signal to the RF tag, which based on an information code stored in a memory, phase-modulates the interrogation signal to produce a backscatter response signal that is transmitted back to the interrogator. A phase modulator structure in the RF tag may include a switch coupled between an antenna and a quarter-wavelength stub; and a driver coupled between the memory and a control terminal of the switch. The driver is structured to produce a modulating signal corresponding to the information code, the modulating signal alternately opening and closing the switch to respectively decrease and increase the transmission path taken by the interrogation signal and thereby modulate the phase of the response signal. Alternatively, the phase modulator may include a diode coupled between the antenna and driver.

Abstract: A transponder device having multiple modes of operation, such as an active mode and a passive mode, wherein the modes of operation are selected in response to the strength of a received radio frequency signal. A communication system is also provided having a transceiver configured to transmit a radio frequency signal and to receive a responsive signal, and a transponder configured to operate in a plurality of modes and to activate modes of operation in response to the radio frequency signal. Ideally, each mode of operation is activated and deactivated independent of the other modes, although two or more modes may be concurrently operational.

Abstract: A system for remotely monitoring the status of one or more fire extinguishers includes means for sensing at least one parameter of each of the fire extinguishers; means for selectively transmitting the sensed parameters along with information identifying the fire extinguishers from which the parameters were sensed; and means for receiving the sensed parameters and identifying information for the fire extinguisher or extinguishers at a common location. Other systems and methods for remotely monitoring the status of multiple fire extinguishers are also provided.

Abstract: A system and method for controlling remote devices utilizing a radio frequency identification (RFID) tag device having a control circuit adapted to render the tag device, and associated objects, permanently inoperable in response to radio-frequency control signals. The control circuit is configured to receive the control signals that can include an enable signal, and in response thereto enable an associated object, such as a weapon; and in response to a disable signal, to disable the tag itself, or, if desired, to disable the associated weapon or both the device and the weapon. Permanent disabling of the tag can be accomplished by several methods, including, but not limited to, fusing a fusable link, breaking an electrically conductive path, permanently altering the modulation or backscattering characteristics of the antenna circuit, and permanently erasing an associated memory.

Abstract: A method and device for remote monitoring of conditions and control of objects that includes an antenna configured to receive and send radio frequency signals, a receiver configured to receive the radio frequency signal and to operate from the power of the received radio frequency signals, a microcontroller coupled to the receiver and configured to respond to the radio frequency signals to report a condition and to control an associated object. The microcontroller may be powered by the radio frequency signal or may receive power from a stored energy source or an external power source.

Abstract: A system and method of inventorying multiple objects utilizing a multi-level or a chained radio frequency identification system. The system includes a master tag and a plurality of upper level tags and lower level tags associated with respective objects. The upper and lower level tags communicate with each other and the master tag so that reading of the master tag reveals the presence and absence of upper and lower level tags. In the chained RF system, the upper and lower level tags communicate locally with each other in a manner so that more remote tags that are out of range of some of the upper and lower level tags have their information relayed through adjacent tags to the master tag and thence to a controller.

Abstract: A system for reducing security risks in, for example, an enclosed area where there are documents, computer discs, and other items which may contain security sensitive information. Each security sensitive item has an RFID tag attached thereto, and during non-working hours these items are placed in locked file cabinets, a safe or a vault. The area is periodically interrogated by an RF interrogator to ascertain whether the items are in their locked secured position or are in an open area.

Abstract: A radio frequency identification system having a radio frequency transceiver for generating a continuous wave RF interrogation signal that impinges upon an RF identification tag. An oscillation circuit in the RF identification tag modulates the interrogation signal with a subcarrier of a predetermined frequency and modulates the frequency-modulated signal back to the transmitting interrogator. The interrogator recovers and analyzes the subcarrier signal and determines its frequency. The interrogator generates an output indicative of the frequency of the subcarrier frequency, thereby identifying the responding RFID tag as one of a “class” of RFID tags configured to respond with a subcarrier signal of a predetermined frequency.

Abstract: A multi-frequency RFID remote communication system is provided that includes a plurality of RFID tags configured to receive a first signal and to return a second signal, the second signal having a first frequency component and a second frequency component, the second frequency component including data unique to each remote RFID tag. The system further includes a reader configured to transmit an interrogation signal and to receive remote signals from the tags. A first signal processor, preferably a mixer, removes an intermediate frequency component from the received signal, and a second processor, preferably a second mixer, analyzes the IF frequency component to output data that is unique to each remote tag.

Abstract: A system for remotely monitoring the status of one or more fire extinguishers includes means for sensing at least one parameter of each of the fire extinguishers; means for selectively transmitting the sensed parameters along with information identifying the fire extinguishers from which the parameters were sensed; and means for receiving the sensed parameters and identifying information for the fire extinguisher or extinguishers at a common location. Other systems and methods for remotely monitoring the status of multiple fire extinguishers are also provided.

Abstract: A security system for a building facility where radio frequency tamper-indicating devices are placed in the area of the facility to detect movement and/or relative movement of components under circumstances where such movement may indicate a security risk. One example is where there are ceiling tiles in a false ceiling which may be moved during a covert entry. An RF damage indicating device is placed at juncture locations of the tiles and tendrils of the tamper-indicating devices are positioned so that movement of one of the tiles will break the tendril and cause an alarm signal to be given. In other arrangements, tamper-indicating devices could be attached to security-sensitive objects, containers for the same, and building-related components so that movement of these security-sensitive objects would also trigger an alarm.

Abstract: A system for reducing security risks in, for example, an enclosed area where there are documents, computer discs, and other items which may contain security sensitive information. Each security sensitive item has an RFID tag attached thereto, and during non-working hours these items are placed in locked file cabinets, a safe or a vault. The area is periodically interrogated by an RF interrogator to ascertain whether the items are in their locked secured position or are in an open area.

Abstract: A system for reducing security risks in, for example, an enclosed area where there are documents, computer discs, and other items which may contain security sensitive information. Each security sensitive item has an RFID tag attached thereto, and during non-working hours these items are placed in locked file cabinets, a safe or a vault. The area is periodically interrogated by an RF interrogator to ascertain whether the items are in their locked secured position or are in an open area.

Abstract: A radio frequency identification system having a radio frequency transceiver for generating a continuous wave RF interrogation signal that impinges upon a RF identification tag. An oscillation circuit in the RF identification tag modulates the interrogation signal with a subcarrier of a predetermined frequency and modulates the frequency-modulated signal back to the transmitting interrogator. The interrogator recovers and analyzes the subcarrier signal and determines its frequency. According to one aspect of the invention, the interrogator generates an output indicative of the frequency of the subcarrier frequency, thereby identifying the responding RFID tag as one of a “class” of RFID tags configured to respond with a subcarrier signal of a predetermined frequency.

Abstract: A system and method for controlling remote devices utilizing a radio frequency identification (RFID) tag device having a control circuit adapted to render the tag device, and associated objects, permanently inoperable in response to radio-frequency control signals. The control circuit is configured to receive the control signals that can include an enable signal, and in response thereto enable an associated object, such as a weapon; and in response to a disable signal, to disable the tag itself, or, if desired, to disable the associated weapon or both the device and the weapon. Permanent disabling of the tag can be accomplished by several methods, including, but not limited to, fusing a fusable link, breaking an electrically conductive path, permanently altering the modulation or backscattering characteristics of the antenna circuit, and permanently erasing an associated memory.