Koichi Sekiguchi 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).
Abstract: An intercom calling apparatus in a key telephone system including a page switch for switching the transmitter from a talking circuit network to an intercom calling path while a contemporaneous call on a central office line is held by the series combination of a resister and a varistor forming a parallel circuit with the transmitter in the talking circuit network.
Abstract: An indicator comprises first means adapted for emitting a ray of light; and second means having an indicating surface for receiving the ray of light to permit the ray of light to illuminate the indicating surface. The first and second means are movable relative to each other to vary intensity of illumination of the indicating surface.
Abstract: A rotary dial device for a telephone set, in which an additional function of preventing a toll dialling is provided. In accordance with this invention, a contact is further attached to an usual dial to classify dial impulses so that when a number "1," one of numbers "2" to "9," and a number "0" are dialled, one, two and three pulses are produced respectively. The dialling function subsequent to the first dialling number "0" and the first and second dialling numbers "10" is effectively stopped by counting the classified pulses.
Abstract: A visual indicator control circuit for use in key telephone systems is disclosed. The circuit includes a plurality of light emitting diodes connected in series and operated by a plurality of transistors having collector-emitter paths connected in parallel with the light emitting diodes. Circuits are provided for controlling the respective base electrode voltages of the transistors corresponding to the use status of each line to control the light emitting diodes corresponding to the on or off states of the transistors.