Patents by Inventor David Charles Naylor

David Charles Naylor 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: 4001513
    Abstract: Fraudulent toll telephone calls are detected by the recognition of extraneous supervisory signals which are generated in the originating office in response to a perpetrator placing such a call. The invention provides a means of detecting a second proceed-to-send signal received at the originating office and of recording in memory means the identities of the calling and called parties. Timing means for achieving the detection is connected to the automatic message accounting trunk circuit of the originating office and, upon detection, an MF receiver is also connected thereto for a predetermined interval of time.
    Type: Grant
    Filed: July 31, 1975
    Date of Patent: January 4, 1977
    Assignee: Northern Electric Company Limited
    Inventor: David Charles Naylor