Abstract: An apparatus and process for identifying objects marked by a magnetic band or thin filament comprising detecting the passage of the magnetic band in a detection zone comprising a framework having an excitation coil fed with alternating current to produce an alternating magnetic field and a detecting coil balanced with the excitation coil such that no signal normally will appear in the absence of a magnetic body in proximity to the framework. The passage of an object carrying a magnetic band in proximity to the framework producing for each alternation of the excitation field an unbalance in a detecting circuit and the appearance of a signal which is fed to apparatus for the detection and measurement of the phase of the signal with respect to the excitation field.

Abstract: A cross bar switching matrix for electric conductors in two sets has a first array of strips of magnetic metal mounted parallel on an insulating support plate with laterally projecting tongues from each strip the ends lying freely on the support plate. A second set of metal strips identical to the first set but at right angles thereto is mounted on a second insulating support plate. The support plates are juxtaposed with the strips perpendicular to each other and the free ends of the tongues of each set are opposed and form with a portion of each of the associated strips a ring which is substantially closed but for a thin layer of electrically insulating material in the areas where the strips of each array cross those of the other. Electromagnetic control circuits made up of electric control conductors are associated with a respective one of the strips and each electric control conductor includes a conductor linked with each of the rings formed by the tongues of the respective array strip.