Patents by Inventor Don C. Springer

Don C. Springer 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: 4000376
    Abstract: A privacy device for a telephone to prevent, unless desired, another telephone from being connected to the pair of incoming lines to which the telephone is connected. The privacy device employs voltage responsive means which is effective upon the telephone being connected to the incoming lines to establish a low impedance connection to the telephone only if the voltage across the incoming lines has initially at least a predetermined value. The low impedance connection drops the voltage across the incoming lines so that other telephones with the privacy device cannot be connected thereto. Means are provided for temporarily increasing the impedance across the lines to increase the voltage so that another telephone can be connected to the line when desired. This is done in a manner not to interrupt the connection between the lines but to maintain a minimum amount of current flowing therethrough so that the central office equipment does not detect an interruption in the line.
    Type: Grant
    Filed: March 31, 1975
    Date of Patent: December 28, 1976
    Assignee: Viking Electronics, Inc.
    Inventor: Don C. Springer