Patents Assigned to Digital Products Corporation
  • Patent number: 5103474
    Abstract: A personnel monitoring system for monitoring presence or absence of particular individuals at preassigned monitoring locations. A local unit is provided at each monitoring location for detecting presence or absence. Each local unit is arranged for short range radio communication with a mobile unit, so that the presence or absence information from the local units may be obtained by brining the mobile unit into proximity with the various local units, as by an officer traveling near the various monitoring location in series. Each local unit may include the base unit of a standard cordless telephone, whereas the mobile unit may include the portable unit of such a telephone. The system desirably provides intercom communication between the mobile unit and the local unit when selected by the monitoring officer, so that the officer can communicate with the monitored person as desired.
    Type: Grant
    Filed: May 8, 1990
    Date of Patent: April 7, 1992
    Assignee: Digital Products Corporation
    Inventors: Veronica Stoodley, Ronald C. Davies
  • Patent number: 5075670
    Abstract: A signalling tag of the type used in house arrest systems has a tamper detection device for detecting removal of the tag from the monitored person. The signal is set to a tamper condition upon removal. The tamper detector can only be reset to the normal state by a reset signal which incorporates a characteristic of the signal sent by the tag. This provides enhanced protection against attempts by the monitored person to defeat the system through unauthorized resetting.
    Type: Grant
    Filed: August 1, 1990
    Date of Patent: December 24, 1991
    Assignee: Digital Products Corporation
    Inventors: David S. Bower, Ronald C. Davies
  • Patent number: 5032823
    Abstract: A personnel monitoring system includes a tag worn by each monitored person. The tag repeatedly emits digital radio signals, and a predetermined bit in the signal changes with time according to a predetermined pattern. Monitoring apparatus detects the radio signals and sends an absence alarm signal if the signals cease. The monitoring apparatus detects spurious, forged signals which do not replicate the predetermined pattern of variation and provides a forgery alarm signal. The tag may be attached to the person by a strap bearing parallel electrical conductors. Attempts to remove the tag by servering the strap cause electrical contact between the conductors. Such contact triggers a detector, which in turn alters the ratio signal.
    Type: Grant
    Filed: August 10, 1990
    Date of Patent: July 16, 1991
    Assignee: Digital Products Corporation
    Inventors: David S. Bower, Ronald C. Davies, Donald E. Garee
  • Patent number: 4924211
    Abstract: A system for monitoring presence of persons at preselected monitoring locations. A plurality of local units, one at each monitoring location, determines whether the monitored person is present or absent at the monitoring location and sends report signals via free space radio transmission. A mobile unit, preferably mounted in a vehicle, passes within range of the various local units in order, and hence recovers status information. Desirably, the mobile unit provides a perceptible signal to an officer in the vehicle if the monitored person is absent. Each local unit may be arranged to receive radio signals from a tag carried by the monitored person and to provide an absence indication if the tag signals are no longer received. The same radio receiver as employed to receive the tag signals may also be employed to receive a callout signal sent by the mobile unit.
    Type: Grant
    Filed: October 28, 1988
    Date of Patent: May 8, 1990
    Assignee: Digital Products Corporation
    Inventor: Ronald C. Davies
  • Patent number: 4747120
    Abstract: A monitoring system for indicating the presence of a person at a remote location through a telephone line includes circuitry at a central location for automatically establishing a telephone link between the central and remote locations. A decoder at the remote location produces a verification signal in response to an action performed by the person whose presence is to be indicated. The decoder transmits the verification signal through the telephone line to the central location to indicate the presence of the person at the remote location.
    Type: Grant
    Filed: August 13, 1985
    Date of Patent: May 24, 1988
    Assignee: Digital Products Corporation
    Inventor: Steven L. Foley
  • Patent number: 4696385
    Abstract: Electronic coin or token detector apparatus is provided in accordance with the teachings of the present invention wherein a predetermined parameter of a coin under test is measured to determine genuineness and surface reflectivity is tested to insure a selected threshold level is present. The coin under test is treated as authentic only if both conditions are satisfied.
    Type: Grant
    Filed: June 5, 1984
    Date of Patent: September 29, 1987
    Assignee: Digital Products Corporation
    Inventor: Ronald C. Davies
  • Patent number: 4678994
    Abstract: Methods and apparatus for sensing, switching and modulating relying upon apparent resonant properties of thin conductive materials are provided in accordance with the teachings of the present invention. According to the present invention, an output of an oscillating circuit is selectively varied as a function of the relationship between a coil within the oscillating circuit, a thin conductive member and the apparent resonant condition of the thin conductive member to achieve appropriate sensing, switching and modulating conditions.
    Type: Grant
    Filed: June 27, 1984
    Date of Patent: July 7, 1987
    Assignee: Digital Products Corporation
    Inventor: Ronald C. Davies
  • Patent number: 4569522
    Abstract: A gaming apparatus uses a group of distinctively colored marbles which are released to travel down an inclined path consisting of four mutually perpendicular segments. A series of deflecting pins are provided along the path for randomizing movement of the marbles free of any influence by the user. A series of steps and crowns are provided to prevent the marbles from being stopped by the pins. A slot is provided for accepting tokens or coins for placement of wagers with regard to the order in which the marbles will arrive at the finishing position. A mechanism is provided for identifying the sequence of finish and determining the outcome of the wagers. The movement of the marbles is at all times visible to the user to provide enjoyment and excitement.
    Type: Grant
    Filed: December 10, 1982
    Date of Patent: February 11, 1986
    Assignee: Digital Products Corporation
    Inventor: Ronald C. Davies
  • Patent number: 4533141
    Abstract: A gaming apparatus wherein a group of rolling elements each having a visible identification characteristic are released to travel down an inclined path. Disposed upon the inclined path are a plurality of deflectors each incorporating structure for precluding the rolling elements from being undesirably caught thereby. The deflection elements cause a randomization of the movable elements at the bottom of the inclined path. A wagering structure is provided for accepting wagers from the user as to the order of which the elements will arrive at a designated finishing position and processing components are provided for determining the outcome of the wagers as a result of the sequencing of the movable elements. During the movement of the movable elements and the random selection of the winner, the user can watch the random selection thereby enhancing enjoyment during the selection process.
    Type: Grant
    Filed: December 10, 1982
    Date of Patent: August 6, 1985
    Assignee: Digital Products Corporation
    Inventors: Steven L. Foley, David S. Bower
  • Patent number: 4438296
    Abstract: Multimessage automatic telephone polling methods and apparatus are provided wherein, telephone numbers for automatic dialing are selected from a queue upon a basis of least prior unsuccessful attempts at calling each telephone number. Thereafter, selection occurs upon the basis of association with the message in place at the playback station to insure that media displacement is maintained at a minimum. Thus, a selected number of attempts at calling each telephone number in the list is performed in a sequence calculated to achieve maximum operation efficiency and minimum media wear.
    Type: Grant
    Filed: September 2, 1980
    Date of Patent: March 20, 1984
    Assignee: Digital Products Corporation
    Inventor: Fred J. Smith
  • Patent number: 4356348
    Abstract: Methods and apparatus for detecting a condition of response on a telephone line are disclosed in accordance with the teachings of the present invention wherein time intervals between the zero crosspoints of an input signal are ascertained and the most prevalent interval determined. The most prevalent interval determined is compared with succeeding time intervals of the input signal and the results of such comparison are employed in classifying the input signal as periodic or not. The nature of the periodic or non-periodic signals are further analyzed to ascertain the condition on the line and an absence of signal for a selected period following a detection of periodic or non-periodic input signals may then be relied upon to indicate that an announce operation may be initiated.
    Type: Grant
    Filed: December 7, 1979
    Date of Patent: October 26, 1982
    Assignee: Digital Products Corporation
    Inventor: Fred J. Smith
  • Patent number: 4201896
    Abstract: A telephone polling apparatus uses an energy detection device in cooperation with timing elements to provide discrimination between various conditions on the telephone line. These conditions are (1) a busy condition, (2) an answer condition, which can occur with someone speaking, not speaking, or with a recorded announcement, and (3) a no answer condition.
    Type: Grant
    Filed: July 3, 1978
    Date of Patent: May 6, 1980
    Assignee: Digital Products Corporation
    Inventors: David S. Bower, Fred J. Smith
  • Patent number: 4188510
    Abstract: A telephone sequential dialer features a shift register which has a number of bit positions which are one more than the maximum number of digits to be dialed. A plurality of consecutive ONES starting at the leading edge of the shift register are inserted into it, the number of ONES inserted being equal to the difference between the number of shift register bit positions and the number of digits of the telephone number to be called. The digits of the telephone number to be called are inserted into a counter whenever a ONE is detected in the shift register by a scanning means, and a dial pulse is generated whenever the counter is decremented. The dial pulses are no longer generated when the counter reaches zero.
    Type: Grant
    Filed: July 3, 1978
    Date of Patent: February 12, 1980
    Assignee: Digital Products Corporation
    Inventors: David S. Bower, Fred J. Smith
  • Patent number: 4160125
    Abstract: Telephone polling apparatus is disclosed for supplying a prerecorded message to a plurality of telephone subscriber stations in sequence and recording responses from the stations after supplying the message thereto. The apparatus stores a telephone number to be called, couples the apparatus to a telephone line, and responds to a dial tone on the telephone line to place a call over the telephone line to the station identified by the stored telephone number. An energy detection device in cooperation with timing elements provides discrimination between a busy condition, an answer condition, a recorded announcement condition, and a no answer condition on the telephone line. When an answer condition is detected, the prerecorded message is transmitted over the telephone line, and, at the end thereof, a recording medium is coupled to the telephone line for recording a response to the message. A selectively variable time period is provided for recording the response.
    Type: Grant
    Filed: May 23, 1977
    Date of Patent: July 3, 1979
    Assignee: Digital Products Corporation
    Inventors: David S. Bower, Fred J. Smith