Patents by Inventor John N. Kerns

John N. Kerns 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: 4394543
    Abstract: A telephone line holding circuit is disclosed which is adapted for temporary connection across a telephone line to maintain that line in a hold condition while line measurements and tests are being performed. The holding circuit is designed to be used over a wide range of line supply voltages and line resistances without introducing line measurement errors. The holding circuit includes a current regulator which maintains the line current at a predetermined level as long as the voltage appearing across the line remains above a predetermined voltage level. The holding circuit also includes a voltage regulator which reduces the predetermined current level to a value which prevents the average line voltage from being reduced below the predetermined voltage level. The holding circuit further includes circuit elements for protecting the circuit elements from damage caused by the application of excessive voltage on the line.
    Type: Grant
    Filed: June 4, 1981
    Date of Patent: July 19, 1983
    Assignee: Lear Siegler, Inc.
    Inventors: Francis P. Keiper, Jr., John N. Kerns