Patents by Inventor Richard C. Fitch

Richard C. Fitch 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).

  • Telephone line carrier system
    Patent number: 4807225
    Abstract: A telephone line carrier system comprising a master station (221) and one or more remote stations (222) is disclosed. Each station (221, 222) is bridged, in a parallel electrical connection, onto a wire-pair (201) that extends from the station to a telephone line switching system. Each station (221, 222) includes a line interface (110, 310) for connecting to the wire-pair (201) at voiceband frequencies, and a radio frequency interface (700, 800) for connecting to the wire-pair (201) at Radio Frequencies (RF). Each station further includes multiplexer and demultiplexer equipment (500, 600) for frequency shifting voice and data channels between baseband and RF. Frequency modulation and full duplex transmission are used for voice communication while amplitude modulation and half-duplex transmission are used for data communication.
    Type: Grant
    Filed: February 2, 1987
    Date of Patent: February 21, 1989
    Assignee: American Telephone and Telegraph Company, AT&T Technologies, Inc.
    Inventor: Richard C. Fitch