Patents by Inventor John Mason Catterall

John Mason Catterall 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 station make-busy circuit
    Patent number: 3997735
    Abstract: A telephone central office trunk utilized for establishing connections of calling telephone station lines with a called telephone station line is arranged to enable a subscriber to make a called telephone station appear busy to incoming calls. The trunk is provided with apparatus arranged to respond to the momentary appearance of a low impedance across the called telephone station line in response to ringing signals applied thereto by opening the established connections and applying busy tone to the calling telephone station lines.
    Type: Grant
    Filed: September 24, 1975
    Date of Patent: December 14, 1976
    Assignee: Bell Telephone Laboratories, Incorporated
    Inventor: John Mason Catterall