Patents by Inventor Nicolaas C. van Zijl

Nicolaas C. van Zijl has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5357244
    Abstract: A pager system includes a transmitter with a control unit for selectively transmitting radio signals having specific pager codes, and a plurality of portable pager receivers each having its own electrical energy source and adapted to respond to a specific pager code. The pager system further includes a central unit coupled to the control unit. The central unit includes a comparing unit and is coupled to a first memory for storing information relating to the individual pager receivers, a second memory for storing reference data, a clock, and a presentation unit. The comparing unit compares the contents of the first and second memories for a specific receiver and clock data, and signals the transmitter when a code signal is needed. The presentation unit generates a warning signal in response to a code signal received from the transmitter.
    Type: Grant
    Filed: June 5, 1992
    Date of Patent: October 18, 1994
    Assignee: Ericsson Radio Systems B.V.
    Inventor: Nicolaas C. van Zijl