Patents by Inventor James Tyler Holt

James Tyler Holt 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 receiver-off-hook detector
    Patent number: 4034162
    Abstract: First and second alternating signals at a central office are applied to a telephone subscriber's lines. The level of the second signal current is used to control the level of the first signal. The nonlinear impedance vs. voltage characteristic of the subscriber's telephone in an off-hook state causes harmonics of the first signal to be generated. Harmonics so generated are detected at the central office to indicate the presence of a receiver-off-hook telephone.
    Type: Grant
    Filed: June 28, 1976
    Date of Patent: July 5, 1977
    Assignee: Bell Telephone Laboratories, Incorporated
    Inventor: James Tyler Holt