Patents by Inventor Jorg Robra

Jorg Robra 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: 4595796
    Abstract: A method of and a circuit for determining current criteria in a subscriber's loop of a telephone system are described. Two constant-current sources are symmetrically connected to two wires of the loop and are controlled by an adjustable reference voltage source. Voltage signals on the voltage source are evaluated in a detecting circuit to determine the actuation of a ground button on the subscriber's set or the occurrence of a ground short-circuit. A testing device is connectable to the subscriber's loop to simulate various conditions of the subscriber's set.
    Type: Grant
    Filed: September 27, 1982
    Date of Patent: June 17, 1986
    Assignee: Te Ka De Felten & Guilleaume Fernmeldeanlagen GmbH
    Inventors: Jorg Robra, Hans Goschin