Patents by Inventor Andrew J. Hefley

Andrew J. Hefley 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).

  • Speakerphone test set
    Patent number: 5193107
    Abstract: A telephone test set that performs dry loop testing of telephone lines has a passive speech network, a speakerphone circuit, and an amplifier and a speaker coupled to the speakerphone circuit. The passive speech network and the speakerphone circuit area isolated by the use of latching relays which are switched by a relay driver circuit that provides a short current burst. Line power can be used to power the speakerphone, so as to extend battery life of a battery which can augment the line power as needed.
    Type: Grant
    Filed: September 20, 1991
    Date of Patent: March 9, 1993
    Assignee: Harris Corporation
    Inventors: Geoffrey H. Parker, Andrew J. Hefley