Abstract: A method for controlling a display device, such as, for example, the display device mounted on a shopping cart, the shopping cart having a wheeled base and a basket portion in connection with the wheeled base and a handle in connection with the wheeled base, the method comprising: allowing a user to enter information at and obtain information from the display device; and providing a locking mechanism located on or implemented within the device for permitting the user to activate or deactivate the display device in order to prevent unauthorized access.

Abstract: A system for sensing paper on a paper roll includes an ultrasonic transducer positioned to be in contact with an outer surface of the paper roll; a transmitter circuit in communication with the ultrasonic transducer, the transmitter circuit providing a transmit signal to the ultrasonic transducer, the ultrasonic transducer generating an ultrasonic signal in response to the transmit signal; a receiver circuit in communication with the ultrasonic transducer, the receiver circuit providing a received signal indicative of an ultrasonic return echo from the paper roll, the ultrasonic return echo resulting from the ultrasonic signal interacting with the paper roll; and a processor circuit, in communication with the transmitter circuit and the receiver circuit, that determines an amount of paper remaining on the paper roll in response to the transmit signal and the receive signal, the processor providing an output signal when the amount of paper remaining falls below a threshold.

Abstract: A fault detector apparatus for a printer having a first print head and a second print head with a plurality of print head elements in each print head is disclosed. The apparatus includes a test circuit in signal communication with all the print heads to test the plurality of print head elements. The test circuit includes a test power supply for generating a test voltage, a first resistor, a second resistor, and an analog to digital converter in signal communication with the second resistor. The first resistor is in series connection between the test power supply and the plurality of elements in the first print head. The second resistor in series connection with the test power supply, the first resistor, and the plurality of elements in the second print head. The fault detector apparatus will also work for a printer with only one print head.

Abstract: The present invention discloses a marking system (102) which detects an identifying feature (112) on an item (110) in a field of view (114), and creates a mark or annotation (204, 208) on the item using a laser source (120). While the marking process commences, the system monitors the field of view to detect if the field of view changes in an unacceptable way. Such unacceptable changes include if the item is removed from the field of view or if the field of view has become obstructed (712), potentially creating an unsafe exposure to the laser source. Upon detecting such a condition the laser source is shut down (718) within a prescribed period of time to prevent an unsafe exposure.

Abstract: A method for sensing paper on a paper roll is disclosed. The method comprises transmitting an ultrasonic signal into the paper roll and detecting an ultrasonic return echo transmit signal from the paper roll, the ultrasonic return echo transmit signal resulting from the ultrasonic signal interacting with the paper roll. Moreover, the method comprises determining an amount of paper remaining on the paper roll in response to the ultrasonic return echo transmit signal. Furthermore, the method may comprise indicating that the paper roll needs to be replaced in response to determining the amount of paper remaining on the paper roll.

Abstract: A system for sensing paper on a paper roll includes an ultrasonic transducer positioned to be in contact with an outer surface of the paper roll; a transmitter circuit in communication with the ultrasonic transducer, the transmitter circuit providing a transmit signal to the ultrasonic transducer, the ultrasonic transducer generating an ultrasonic signal in response to the transmit signal; a receiver circuit in communication with the ultrasonic transducer, the receiver circuit providing a received signal indicative of an ultrasonic return echo from the paper roll, the ultrasonic return echo resulting from the ultrasonic signal interacting with the paper roll; and a processor circuit, in communication with the transmitter circuit and the receiver circuit, that determines an amount of paper remaining on the paper roll in response to the transmit signal and the receive signal, the processor providing an output signal when the amount of paper remaining falls below a threshold.

Abstract: A mobile platform such as a shopping cart, flatbed cart or lift truck is provided with a plurality of radiation detectors which are screened or limited in scope of view and which cooperate with circuitry which can distinguish from the interaction of the sensors with emitters the position of the platform. Position consists of location and orientation. Each detector or sensor is screened to limit its view to a defined portion of a sphere.

Abstract: A fault detector apparatus for a printer having a first print head and a second print head with a plurality of print head elements in each print head is disclosed. The apparatus includes a test circuit in signal communication with all the print heads to test the plurality of print head elements. The test circuit includes a test power supply for generating a test voltage, a first resistor, a second resistor, and an analog to digital converter in signal communication with the second resistor. The first resistor is in series connection between the test power supply and the plurality of elements in the first print head. The second resistor in series connection with the test power supply, the first resistor, and the plurality of elements in the second print head. The fault detector apparatus will also work for a printer with only one print head.

Abstract: A system includes an ultrasonic transducer positioned to be in contact with the outer surface of a paper roll. The system further includes a transmitter circuit and a receiver circuit in communication with the ultrasonic transducer. The transmitter circuit provides a transmit signal to the ultrasonic transducer for generating an ultrasonic signal, which is transmitted into the paper roll. The receiver circuit provides a received signal indicative of an ultrasonic return echo from the paper roll. The ultrasonic return echo resulting from the ultrasonic signal interacting with the paper roll. The system also includes a processor circuit for determining an amount (length or diameter of roll) of paper remaining on the paper roll in response to the transmit signal and the receive signal. The processor provides an output signal when the amount of paper remaining falls below a threshold. A method of sensing paper on a paper roll is also presented.

Abstract: A mobile platform such as a shopping cart, flatbed cart or lift truck is provided with a plurality of radiation detectors which are screened or limited in scope of view and which cooperate with circuitry which can distinguish from the interaction of the sensors with emitters the position of the platform. Position consists of location and orientation. Each detector or sensor is screened to limit its view to a defined portion of a sphere.

Abstract: A method for controlling a display device, such as, for example, the display device mounted on a shopping cart, the shopping cart having a wheeled base and a basket portion in connection with the wheeled base and a handle in connection with the wheeled base, the method comprising: allowing a user to enter information at and obtain information from the display device; and providing a locking mechanism located on or implemented within the device for permitting the user to activate or deactivate the display device in order to prevent unauthorized access.

Abstract: A video source provides information to a communication device that results in an icon being displayed on the communications device during a preview of a television program or segment of a television program. The icon indicates to the user that a single button on a remote control or other user-controller device can be used to program the communication device, including television, video-cassette recorders, cable boxes, network computers, or the like, to display or record the desired program or program segment as the program segment is being televised or communicated. Specifically, during operation, the exact date, time, and source of the actual television program or program segment is encoded in an unused portion of a teletext data stream when the icon is present. If the communication device receives an appropriate command from its user-controlled device while the icon is displayed, a central processing unit within that communication device, saves the information together with a channel presently being viewed.

Abstract: Apparatus and method are disclosed for communicating between a central location and a plurality of identification tags or labels located in a container or in a space without separately passing each tag or labeled product through a read station. The disclosure includes use of hashing to reduce the amount of time needed to read the possible tags in the space. Reading is accomplished using radio communication with a combination of broadcast and time division multiplex architectures.

Abstract: An apparatus and method for ultrasonically communicating information from a source to a destination and for acknowledging receipt of that information by the destination. The apparatus includes at least one processor, at least one transceiver, and at least one display device, each display device having a unique identifier. The processor communicates information for broadcast to the transceiver. The processor also performs digital signal processing for detecting an acknowledgement signal within a narrow bandwidth. The transceiver ultrasonically broadcasts an identifier and associated data to display devices within the broadcast area, and also receives ultrasonic signals. A display device includes a transducer, a comparator, a memory, a display panel, and logic. In the communication method, a processor, a transceivers, and a display device communicate by initially associating data with a unique display device identifier.

Abstract: A data source on a main local area network (LAN) transmits broadcast messages via bridges to remote stations. A ring buffer in a bridge on the main LAN buffers a selected number of packets received from the data source. When the main bridge on the main LAN receives a "Lost Frame Message" from a remote bridge, not on the main LAN, the main bridge backs up to the address of the lost packet in the ring buffer, and retransmits the lost packet and then continues sequential transmission of subsequent packets. If buffer is, filled above a pre-set criteria, retransmission is slowed or stopped until buffer is mostly emptied.

Abstract: A free space laser communication system operates at two power levels. The system includes a microprocessor to control the laser output beam to a safety level when the input beam indicates that the output beam is not being received at the remotely positioned terminal. If the output beam is not being received by the remotely positioned terminal, a blockage or misalignment of the beam is indicated. During normal operation when a blockage or misalignment of the beam is not detected, the output beam may be operated at a level higher than a safety limit to thereby provide enhanced communication performance.

Abstract: A hybrid of controlled access and random access schemes using frequency hopping spread spectrum communication techniques is implemented in an indoor digital data radio communication system between mobile stations and a computer system. A hop in the frequency hopping spread spectrum communication system is subdivided into two intervals so that different media-access protocols can be used in each interval. The protocol uses a centralized control scheme in one interval and a decentralized scheme in the other, and the intervals may be varied depending on the load of the system.

Abstract: An improved holographic scanner includes circuitry for adjusting the frequency with which an analog photodetector signal is sampled in accordance with the focal length of the scanning beam produced by the active holographic facet. Two embodiments are shown. In one embodiment, facet-edge signals are used to track the facets. A processor retrieves a predetermined frequency scaling factor appropriate for each facet. In the other embodiment, a holographic disk carries an auxiliary data track. The track has timing indicia with spatial frequencies dependent upon the focal length of the adjacent facet. The timing indicia are used to control the output of a voltage controlled oscillator in a circuit including a phase locked loop.

Abstract: A holographic scanner includes a rotating glass disk carrying a plurality of scan line generating holograms, a laser light source and means for detecting reflected optical energy. The scanner is improved by adding a plurality of relatively small position-indicating holograms in alternation with the scan line generating holograms. The position-indicating holograms redirect the laser beam along desired paths on the same side of the disk as the laser. The redirected laser beam may be detected by the system photodetector or an auxiliary photodetector to provide signals indicating the current disk position. The position information can be used by a system processor to optimize scanner parameters as a function of the characteristics of the next active scan line generating hologram.

Abstract: A fixed position optical scanner with a multi-faceted holographic disk includes circuitry for adjusting the lockout voltage as a function of the focal length of the active facet. The disk position is tracked to identify the active facet. A facet identifying signal is used to address a lockout table in processor memory. A digital value retrieved from the lockout table is converted to analog form and applied through a resistor to a voltage divider in the threshold circuit. The voltage divider scales down a white peak following voltage and compares it to a black peak following voltage. The facet-dependent lockout voltage biases the junction of the voltage divider to vary the effective lockout voltage as a function of the focal length of the currently active facet.