Abstract: A multi protocol transponder for a communications network having a antenna for receiving a first RF signal transmitted according to a communications protocol and a detector for identifying the communications protocol from the first RF signal. A protocol controller is provided for executing the identified communications protocol to generate a second RF signal. Thereafter an antenna transmits the second RF signal according to the communications protocol either by active transmission or modulated backscatter. The transponder may implement a variety of wide area and localized lane based protocols for Automatic Vehicle Identification systems such as CVO and Toll systems.

Abstract: A multi protocol transponder for a communications network having a antenna for receiving a first RF signal transmitted according to a communications protocol and a detector for identifying the communications protocol from the first RF signal. A protocol controller is provided for executing the identified communications protocol to generate a second RF signal. Thereafter an antenna transmits the second RF signal according to the communications protocol either by active transmission or modulated backscatter. The transponder may implement a variety of wide area and localized lane based protocols for Automatic Vehicle Identification systems such as CVO and Toll systems.

Abstract: A handheld reader for testing the validity of a transponder in a mobile communications system, such as an electronic toll collection system. The handheld reader interrogates the transponder under test and receives a response signal. The response signal contains a data string having a sequential plurality of fields, including one field earlier in the sequence than another field. The handheld reader tests the later field for validity and, if invalid, tests the earlier field for validity. Based upon the results of the tests, the handheld reader outputs an indicator signal that provides an assessment of the degree of validity of the data string.

Abstract: An RF roadway toll collection system uses an upstream reader to communicate with a vehicle borne transponder carrying a Smart Card to calculate the toll and debit the Smart Card balance in the amount of the toll payment required. A transaction manager is notified of the toll payment from the upstream reader and notifies a downstream reader of the vehicle identification and payment status. The downstream reader confirms the vehicle identification and payment status and signals if the toll has been paid.

Abstract: A small dot or disk flip dot display element and a method of making a flip dot display formed of such elements is shown where the disks or dots flip between an ON position showing a bright surface and an OFF position showing a dark surface. The dots are flipped by electromagnets having poles with a first coil wound thereon for producing a reversible magnetic field operating the flip dots. A second coil is wound on the poles in series with the first coil. The second coil is dipped in molten solder to form an electrical contact for energizing the first coils, and for mounting the elements to a circuit board. Separate terminal pins are not required for electrical connections to the coils, thus allowing flip dots as small as 5 mm or less to be used.

Abstract: A multi protocol transponder for a communications network having a antenna for receiving a first RF signal transmitted according to a communications protocol and a detector for identifying the communications protocol from the first RF signal. A protocol controller is provided for executing the identified communications protocol to generate a second RF signal. Thereafter an antenna transmits the second RF signal according to the communications protocol either by active transmission or modulated backscatter. The transponder may implement a variety of wide area and localized lane based protocols for Automatic Vehicle Identification systems such as CVO and Toll systems.

Abstract: Each element in an array of display elements has first and second limiting positions and in respective limiting positions selectively displays a bright and a dark surface in a viewing direction. A transparent sheet is intermediate the array and the viewer. Conductors on the sheet power light sources in the sheet to thereby direct light toward the array.

Abstract: An array of disks facing a viewing direction is composed of disks rotatable about an axis approximately perpendicular to the viewing direction between alternating orientations where light and dark surfaces are respectively displayed in the viewing direction. There is provided a row of LEDs located forwardly of the array and out of the normal viewing path located to illuminate the disks of said array. Masking means prevents direct illumination from said LED's being visible in the viewing direction. In a further variant the disks' light surfaces contain a fluorescent component and the LEDs are selected to provide radiation including UV spectra.

Abstract: A vehicle position determination system for determining the position of a moving vehicle having a transponder includes a first and second antennas operable to receive periodic radio frequency data signals from the transponder when the transponder is moving through a first or second predetermined coverage zone, respectively. The first and second coverage zones partially overlap and each have a width that is orthogonal to the travel path of the moving vehicle and a length that is parallel to the travel path of the moving vehicle. A processor counts the number of periodic data signals received by each of the antennas from the transponder during a time period and determines based on the count a probable location of the vehicle. The vehicle location information can be provided to an imaging system to discriminate between transponder and non-transponder equipped vehicles.

Abstract: A sign having a changeable array constituted by a plurality of pivotally mounted disks which have opposite bright and dark surfaces. The bright surface of each disk is illuminated by an adjacent light emitter when positioned in a direction of viewing. Light from each light emitter is blocked from illuminating disks other than the adjacent disk in the array.

Abstract: A display element includes a disk which rotates preferably through 160°-180° to display a bright or a dark side in a viewing direction in ON and OFF positions respectively. A constantly on LED is arranged to illuminate the disk in ON position for viewing in a first arc including the viewing direction. The disk masks the LED to viewers in the OFF position of the disk. In addition to light from the illuminated disks, the components may be arranged so that viewers over a second arc may view the LED directly when the disk is in ON position. The elements may be arranged in arrays to form a changeable sign. Thus the array may be made up of single elements, of columns of such elements or of a combination of elements and columns.

Abstract: Traffic management or enforcement is performed through the use of a monitor transponder in the environs of an RF highway toll collection system. When normally operating transponders communicate with a roadside reader system, the roadside system communicates with the monitor transponder, which in turn signals if a valid normal transponder is detected. If no signal is generated by the monitor transponder, it is evident that the vehicle has no transponder or that the transponder is faulty or invalid.

Abstract: A changeable display element is edgewise mounted on an insulating board and carries to rotate through about 180.degree. to show one color face or the other to a viewer. The board provides a similarly colored face for each face to form a pixel. The element carries a permanent magnet and is driven by a switchable magnetic field provided from the board. Soft iron pads on the board cooperate with the magnet on each position to retain the element against incidental displacement between application of the field. The board may support arrays of such elements.

Abstract: A display array including a board resembling a printed circuit board or printed wiring board to which are pivotally mounted a plurality of display elements whose appearance in a viewing direction is controlled by a sense of magnetization of a core which extends through a bore in the board. A conducting coil formed on the surface of the board is located so that current in the coil will magnetize the core.

Abstract: In order to locate a transponder in a roadway there are first and second antenna arrays at spaced locations. Each array is associated with a switching control which causes the array beam to step through a series of beams. The signal developed in each beam is converted to a digital result. The strongest beam from each array may be determined and the location of the transponder at the intersection of the two strongest beams.

Abstract: A changeable display element is edgewise mounted on an insulating board and carries to rotate through about 180.degree. to show one color face or the other to a viewer. The board provides a similarly colored face for each face to form a pixel. The element carries a permanent magnet and is driven by a switchable magnetic field provided from the board. Soft iron pads on the board cooperates with the magnet on each position to retain the element against incidental displacement between application of the field. The board may support arrays of such elements.

Abstract: An array of disks faces a viewing direction is composed of disk's rotatable about an axis approximately perpendicular to the viewing direction between alternating orientations where bright and dark sides are respectively displayed in the viewing direction. There is provided a row of LED's located forwardly of the array and out of the normal viewing path located to illuminate the disks of said array. Masking means prevents direct illumination from said LED's being visible in the viewing direction.

Abstract: Each element in an array of display elements has first and second limiting positions and in respective limiting positions selectively displays a bright and a dark surface in a viewing direction. A transparent sheet is intermediate the array and the viewer. Conductors on said sheet direct light toward said array.

Abstract: A board usually resembling a PCB or a PWB mounts a display element, whose appearance in a viewing direction is controlled by the sense of magnetization of a core which extends through a bore in the board. A conducting coil formed on the surface of said board is located so that current in said coil will magnetize the core.

Abstract: A display element has a disk which rotates on an axis to show its bright or dark side in the viewing direction. When the bright side is showing the disk allows passage of light from an LED. When the dark side is showing the disk masks the light from the LED. Preferably, an opaque shroud surrounds the LED and projects a short distance forwardly thereof to help define the cone in which light from the LED may be viewed in ON position. A side wall of said element projects forwardly of the rotation axis to mask the escape of light on that side transverse to the viewing direction. A second side wall may be placed on the other side for the same purpose or the adjacent element may provide the second wall.